TY - JOUR
A1 - Zeitz, Maria
A1 - Levermann, Anders
A1 - Winkelmann, Ricarda
T1 - Sensitivity of ice loss to uncertainty in flow law parameters in an idealized one-dimensional geometry
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - Acceleration of the flow of ice drives mass losses in both the Antarctic and the Greenland Ice Sheet. The projections of possible future sea-level rise rely on numerical ice-sheet models, which solve the physics of ice flow, melt, and calving. While major advancements have been made by the ice-sheet modeling community in addressing several of the related uncertainties, the flow law, which is at the center of most process-based ice-sheet models, is not in the focus of the current scientific debate. However, recent studies show that the flow law parameters are highly uncertain and might be different from the widely accepted standard values. Here, we use an idealized flow-line setup to investigate how these uncertainties in the flow law translate into uncertainties in flow-driven mass loss. In order to disentangle the effect of future warming on the ice flow from other effects, we perform a suite of experiments with the Parallel Ice Sheet Model (PISM), deliberately excluding changes in the surface mass balance. We find that changes in the flow parameters within the observed range can lead up to a doubling of the flow-driven mass loss within the first centuries of warming, compared to standard parameters. The spread of ice loss due to the uncertainty in flow parameters is on the same order of magnitude as the increase in mass loss due to surface warming. While this study focuses on an idealized flow-line geometry, it is likely that this uncertainty carries over to realistic three-dimensional simulations of Greenland and Antarctica.
Y1 - 2020
U6 - https://doi.org/10.5194/tc-14-3537-2020
SN - 1994-0416
SN - 1994-0424
VL - 14
IS - 10
SP - 3537
EP - 3550
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Albrecht, Torsten
A1 - Winkelmann, Ricarda
A1 - Levermann, Anders
T1 - Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)
BT - Part 1: boundary conditions and climatic forcing
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice sheet and the bedrock. Also climatic forcing covering the last glacial cycles is uncertain, as it is based on sparse proxy data.
We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data, e.g., for modern basal heat flux or reconstructions of past changes of sea level and surface temperature. As computational resources are limited, glacial-cycle simulations are performed using a comparably coarse model grid of 16 km and various parameterizations, e.g., for basal sliding, iceberg calving, or for past variations in precipitation and ocean temperatures. In this study we evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also discuss isolated and combined effects of climate and sea-level forcing. Hence, this study serves as a "cookbook" for the growing community of PISM users and paleo-ice sheet modelers in general.
For each of the different model uncertainties with regard to climatic forcing, ice and Earth dynamics, and basal processes, we select one representative model parameter that captures relevant uncertainties and motivates corresponding parameter ranges that bound the observed ice volume at present. The four selected parameters are systematically varied in a parameter ensemble analysis, which is described in a companion paper.
Y1 - 2020
U6 - https://doi.org/10.5194/tc-14-599-2020
SN - 1994-0416
SN - 1994-0424
VL - 14
IS - 2
SP - 599
EP - 632
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Kreuzer, Moritz
A1 - Reese, Ronja
A1 - Huiskamp, Willem Nicholas
A1 - Petri, Stefan
A1 - Albrecht, Torsten
A1 - Feulner, Georg
A1 - Winkelmann, Ricarda
T1 - Coupling framework (1.0) for the PISM (1.1.4) ice sheet model and the MOMS (5.1.0) ocean model via the PICO ice shelf cavity model in an Antarctic domain
JF - Geoscientific model development : an interactive open access journal of the European Geosciences Union
N2 - The past and future evolution of the Antarctic Ice Sheet is largely controlled by interactions between the ocean and floating ice shelves. To investigate these interactions, coupled ocean and ice sheet model configurations are required. Previous modelling studies have mostly relied on high-resolution configurations, limiting these studies to individual glaciers or regions over short timescales of decades to a few centuries. We present a framework to couple the dynamic ice sheet model PISM (Parallel Ice Sheet Model) with the global ocean general circulation model MOM5 (Modular Ocean Model) via the ice shelf cavity model PICO (Pots-dam Ice-shelf Cavity mOdel). As ice shelf cavities are not resolved by MOM5 but are parameterized with the PICO box model, the framework allows the ice sheet and ocean components to be run at resolutions of 16 km and 3 degrees respectively. This approach makes the coupled configuration a useful tool for the analysis of interactions between the Antarctic Ice Sheet and the global ocean over time spans of the order of centuries to millennia. In this study, we describe the technical implementation of this coupling framework: sub-shelf melting in the ice sheet component is calculated by PICO from modelled ocean temperatures and salinities at the depth of the continental shelf, and, vice versa, the resulting mass and energy fluxes from melting at the ice-ocean interface are transferred to the ocean component. Mass and energy fluxes are shown to be conserved to machine precision across the considered component domains. The implementation is computationally efficient as it introduces only minimal overhead. Furthermore, the coupled model is evaluated in a 4000 year simulation under constant present-day climate forcing and is found to be stable with respect to the ocean and ice sheet spin-up states. The framework deals with heterogeneous spatial grid geometries, varying grid resolutions, and timescales between the ice and ocean component in a generic way; thus, it can be adopted to a wide range of model set-ups.
Y1 - 2021
U6 - https://doi.org/10.5194/gmd-14-3697-2021
SN - 1991-959X
SN - 1991-9603
VL - 14
IS - 6
SP - 3697
EP - 3714
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Zeitz, Maria
A1 - Haacker, Jan M.
A1 - Donges, Jonathan
A1 - Albrecht, Torsten
A1 - Winkelmann, Ricarda
T1 - Dynamic regimes of the Greenland Ice Sheet emerging from interacting melt-elevation and glacial isostatic adjustment feedbacks
JF - Earth system dynamics
N2 - The stability of the Greenland Ice Sheet under global warming is governed by a number of dynamic processes and interacting feedback mechanisms in the ice sheet, atmosphere and solid Earth.
Here we study the long-term effects due to the interplay of the competing melt-elevation and glacial isostatic adjustment (GIA) feedbacks for different temperature step forcing experiments with a coupled ice-sheet and solid-Earth model.
Our model results show that for warming levels above 2 degrees C, Greenland could become essentially ice-free within several millennia, mainly as a result of surface melting and acceleration of ice flow. These ice losses are mitigated, however, in some cases with strong GIA feedback even promoting an incomplete recovery of the Greenland ice volume. We further explore the full-factorial parameter space determining the relative strengths of the two feedbacks: our findings suggest distinct dynamic regimes of the Greenland Ice Sheets on the route to destabilization under global warming - from incomplete recovery, via quasi-periodic oscillations in ice volume to ice-sheet collapse.
In the incomplete recovery regime, the initial ice loss due to warming is essentially reversed within 50 000 years, and the ice volume stabilizes at 61 %-93 % of the present-day volume. For certain combinations of temperature increase, atmospheric lapse rate and mantle viscosity, the interaction of the GIA feedback and the melt-elevation feedback leads to self-sustained, long-term oscillations in ice-sheet volume with oscillation periods between 74 000 and over 300 000 years and oscillation amplitudes between 15 %-70 % of present-day ice volume.
This oscillatory regime reveals a possible mode of internal climatic variability in the Earth system on timescales on the order of 100 000 years that may be excited by or synchronized with orbital forcing or interact with glacial cycles and other slow modes of variability. Our findings are not meant as scenario-based near-term projections of ice losses but rather providing insight into of the feedback loops governing the "deep future" and, thus, long-term resilience of the Greenland Ice Sheet.
Y1 - 2022
U6 - https://doi.org/10.5194/esd-13-1077-2022
SN - 2190-4979
SN - 2190-4987
VL - 13
IS - 3
SP - 1077
EP - 1096
PB - Copernicus Publ.
CY - Göttingen
ER -
TY - JOUR
A1 - Albrecht, Torsten
A1 - Winkelmann, Ricarda
A1 - Levermann, Anders
T1 - Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)
BT - part 2: parameter ensemble analysis
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - The Parallel Ice Sheet Model (PISM) is applied to the Antarctic Ice Sheet over the last two glacial cycles (approximate to 210 000 years) with a resolution of 16 km. An ensemble of 256 model runs is analyzed in which four relevant model parameters have been systematically varied using full-factorial parameter sampling. Parameters and plausible parameter ranges have been identified in a companion paper (Albrecht et al., 2020) and are associated with ice dynamics, climatic forcing, basal sliding and bed deformation and represent distinct classes of model uncertainties. The model is scored against both modern and geologic data, including reconstructed grounding-line locations, elevation-age data, ice thickness, surface velocities and uplift rates. An aggregated score is computed for each ensemble member that measures the overall model-data misfit, including measurement uncertainty in terms of a Gaussian error model (Briggs and Tarasov, 2013). The statistical method used to analyze the ensemble simulation results follows closely the simple averaging method described in Pollard et al. (2016).
This analysis reveals clusters of best-fit parameter combinations, and hence a likely range of relevant model and boundary parameters, rather than individual best-fit parameters. The ensemble of reconstructed histories of Antarctic Ice Sheet volumes provides a score-weighted likely range of sea-level contributions since the Last Glacial Maximum (LGM) of 9.4 +/- 4.1m (or 6.5 +/- 2.0 x 10(6) km(3)), which is at the upper range of most previous studies. The last deglaciation occurs in all ensemble simulations after around 12 000 years before present and hence after the meltwater pulse 1A (MWP1a). Our ensemble analysis also provides an estimate of parametric uncertainty bounds for the present-day state that can be used for PISM projections of future sea-level contributions from the Antarctic Ice Sheet.
Y1 - 2020
U6 - https://doi.org/10.5194/tc-14-633-2020
SN - 1994-0416
SN - 1994-0424
VL - 14
IS - 2
SP - 633
EP - 656
PB - Copernicus Publ.
CY - Göttingen
ER -
TY - JOUR
A1 - Schlemm, Tanja
A1 - Feldmann, Johannes
A1 - Winkelmann, Ricarda
A1 - Levermann, Anders
T1 - Stabilizing effect of melange buttressing on the marine ice-cliff instability of the West Antarctic Ice Sheet
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - Owing to global warming and particularly high regional ocean warming, both Thwaites and Pine Island Glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyse the possible consequences using the parallel ice sheet model (PISM), applying a simple cliff-calving parameterization and an ice melange-buttressing model. We find that the instantaneous loss of ice-shelf buttressing, due to enforced ice-shelf melting, initiates grounding-line retreat and triggers marine ice sheet instability (MISI). As a consequence, the grounding line progresses into the interior of the West Antarctic Ice Sheet and leads to a sea level contribution of 0.6 m within 100 a. By subjecting the exposed ice cliffs to cliff calving using our simplified parameterization, we also analyse marine ice cliff instability (MICI). In our simulations it can double or even triple the sea level contribution depending on the only loosely constrained parameter that determines the maximum cliff-calving rate. The speed of MICI depends on this upper bound of the calving rate, which is given by the ice melange buttressing the glacier. However, stabilization of MICI may occur for geometric reasons. Because the embayment geometry changes as MICI advances into the interior of the ice sheet, the upper bound on calving rates is reduced and the progress of MICI is slowed down. Although we cannot claim that our simulations bear relevant quantitative estimates of the effect of ice-melange buttressing on MICI, the mechanism has the potential to stop the instability. Further research is needed to evaluate its role for the past and future evolution of the Antarctic Ice Sheet.
Y1 - 2022
U6 - https://doi.org/10.5194/tc-16-1979-2022
SN - 1994-0416
SN - 1994-0424
VL - 16
IS - 5
SP - 1979
EP - 1996
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Feldmann, Johannes
A1 - Reese, Ronja
A1 - Winkelmann, Ricarda
A1 - Levermann, Anders
T1 - Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean.
Here we contrast the influence of basal melting in two different ice-shelf regions on the time-dependent response of an isothermal, inherently buttressed ice-sheet-shelf system. In the idealized numerical simulations, the basal-melt perturbations are applied close to the grounding line in the ice-shelf's (1) ice-stream region, where the ice shelf is fed by the fastest ice masses that stream through the upstream bed trough and (2) shear margins, where the ice flow is slower.
The results show that melting below one or both of the shear margins can cause a decadal to centennial increase in ice discharge that is more than twice as large compared to a similar perturbation in the ice-stream region. We attribute this to the fact that melt-induced ice-shelf thinning in the central grounding-line region is attenuated very effectively by the fast flow of the central ice stream. In contrast, the much slower ice dynamics in the lateral shear margins of the ice shelf facilitate sustained ice-shelf thinning and thereby foster buttressing reduction.
Regardless of the melt location, a higher melt concentration toward the grounding line generally goes along with a stronger response. Our results highlight the vulnerability of outlet glaciers to basal melting in stagnant, buttressing-relevant ice-shelf regions, a mechanism that may gain importance under future global warming.
Y1 - 2022
U6 - https://doi.org/10.5194/tc-16-1927-2022
SN - 1994-0416
SN - 1994-0424
VL - 16
IS - 5
SP - 1927
EP - 1940
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Wunderling, Nico
A1 - Willeit, Matteo
A1 - Donges, Jonathan
A1 - Winkelmann, Ricarda
T1 - Global warming due to loss of large ice masses and Arctic summer sea ice
JF - Nature Communications
N2 - Several large-scale cryosphere elements such as the Arctic summer sea ice, the mountain glaciers, the Greenland and West Antarctic Ice Sheet have changed substantially during the last century due to anthropogenic global warming. However, the impacts of their possible future disintegration on global mean temperature (GMT) and climate feedbacks have not yet been comprehensively evaluated. Here, we quantify this response using an Earth system model of intermediate complexity. Overall, we find a median additional global warming of 0.43 degrees C (interquartile range: 0.39-0.46 degrees C) at a CO2 concentration of 400 ppm. Most of this response (55%) is caused by albedo changes, but lapse rate together with water vapour (30%) and cloud feedbacks (15%) also contribute significantly. While a decay of the ice sheets would occur on centennial to millennial time scales, the Arctic might become ice-free during summer within the 21st century. Our findings imply an additional increase of the GMT on intermediate to long time scales. The disintegration of cryosphere elements such as the Arctic summer sea ice, mountain glaciers, Greenland and West Antarctica is associated with temperature and radiative feedbacks. In this work, the authors quantify these feedbacks and find an additional global warming of 0.43 degrees C.
Y1 - 2020
U6 - https://doi.org/10.1038/s41467-020-18934-3
SN - 2041-1723
VL - 11
IS - 1
PB - Nature Publishing Group
CY - Berlin
ER -
TY - JOUR
A1 - Zeitz, Maria
A1 - Reese, Ronja
A1 - Beckmann, Johanna
A1 - Krebs-Kanzow, Uta
A1 - Winkelmann, Ricarda
T1 - Impact of the melt-albedo feedback on the future evolution of the Greenland Ice Sheet with PISM-dEBM-simple
JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2 - Surface melting of the Greenland Ice Sheet contributes a large amount to current and future sea level rise. Increased surface melt may lower the reflectivity of the ice sheet surface and thereby increase melt rates: the so-called melt-albedo feedback describes this self-sustaining increase in surface melting. In order to test the effect of the melt-albedo feedback in a prognostic ice sheet model, we implement dEBM-simple, a simplified version of the diurnal Energy Balance Model dEBM, in the Parallel Ice Sheet Model (PISM). The implementation includes a simple representation of the melt-albedo feedback and can thereby replace the positive-degree-day melt scheme. Using PISM-dEBM-simple, we find that this feedback increases ice loss through surface warming by 60 % until 2300 for the high-emission scenario RCP8.5 when compared to a scenario in which the albedo remains constant at its present-day values. With an increase of 90 % compared to a fixed-albedo scenario, the effect is more pronounced for lower surface warming under RCP2.6. Furthermore, assuming an immediate darkening of the ice surface over all summer months, we estimate an upper bound for this effect to be 70 % in the RCP8.5 scenario and a more than 4-fold increase under RCP2.6. With dEBM-simple implemented in PISM, we find that the melt-albedo feedback is an essential contributor to mass loss in dynamic simulations of the Greenland Ice Sheet under future warming.
Y1 - 2021
U6 - https://doi.org/10.5194/tc-15-5739-2021
SN - 1994-0416
SN - 1994-0424
VL - 15
IS - 12
SP - 5739
EP - 5764
PB - Copernicus
CY - Katlenburg-Lindau
ER -
TY - JOUR
A1 - Klose, Ann Kristin
A1 - Wunderling, Nico
A1 - Winkelmann, Ricarda
A1 - Donges, Jonathan
T1 - What do we mean, 'tipping cascade'?
JF - Environmental research letters : ERL
N2 - Based on suggested interactions of potential tipping elements in the Earth's climate and in ecological systems, tipping cascades as possible dynamics are increasingly discussed and studied. The activation of such tipping cascades would impose a considerable risk for human societies and biosphere integrity. However, there are ambiguities in the description of tipping cascades within the literature so far. Here we illustrate how different patterns of multiple tipping dynamics emerge from a very simple coupling of two previously studied idealized tipping elements. In particular, we distinguish between a two phase cascade, a domino cascade and a joint cascade. A mitigation of an unfolding two phase cascade may be possible and common early warning indicators are sensitive to upcoming critical transitions to a certain degree. In contrast, a domino cascade may hardly be stopped once initiated and critical slowing down-based indicators fail to indicate tipping of the following element. These different potentials for intervention and anticipation across the distinct patterns of multiple tipping dynamics should be seen as a call to be more precise in future analyses of cascading dynamics arising from tipping element interactions in the Earth system.
KW - tipping cascade
KW - domino effect
KW - tipping interactions
KW - cascading regime
KW - shifts
KW - early warning indicators
Y1 - 2021
U6 - https://doi.org/10.1088/1748-9326/ac3955
SN - 1748-9326
VL - 16
IS - 12
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Tiberius, Victor
A1 - Weyland, Michael
T1 - Identifying constituent elements of entrepreneurship curricula
BT - a systematic literature review
JF - Administrative sciences
N2 - Entrepreneurship education research has a strong “output” focus on impact studies but pays much less attention to the “inside” or process perspective of the way entrepreneurship education occurs. In particular, the scattered previous entrepreneurship curriculum research has not managed to provide a current and comprehensive overview of the curricular elements that constitute entrepreneurship education. To overcome this shortcoming, we aim to identify the teaching objectives, teaching contents, teaching methods, and assessment methods discussed in entrepreneurship curriculum research. To this end, we conducted a systematic literature review on the four entrepreneurship curriculum dimensions and collected all mentioned curriculum items. We used a two-stage coding procedure to find the genuinely entrepreneurship-specific items. Among numerous items (also from business management and other subjects), we found 26 objectives, 34 contents, 11 teaching methods, and 7 assessment methods that were entrepreneurship-specific. Most of these items were addressed by only a few scholarly papers.
KW - assessment methods
KW - curriculum
KW - entrepreneurship education
KW - teaching contents
KW - teaching methods
KW - teaching objectives
Y1 - 2023
U6 - https://doi.org/10.3390/admsci14010001
SN - 2076-3387
VL - 14
IS - 1
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Romero Barbosa, Luís
A1 - Coelho, Victor Hugo R.
A1 - Scheiffele, Lena
A1 - Baroni, Gabriele
A1 - Ramos Filho, Geraldo M.
A1 - Montenegro, Suzana M. G. L.
A1 - Das Neves Almeida, Cristiano
A1 - Oswald, Sascha
T1 - Dynamic groundwater recharge simulations based on cosmic-ray neutron sensing in a tropical wet experimental basin
JF - Vadose zone journal : VZJ : advancing critical zone science
N2 - Although cosmic-ray neutron sensing (CRNS) is probably the most promising noninvasive proximal soil moisture measurement technique at the field scale, its application for hydrological simulations remains underexplored in the literature so far. This study assessed the use of CRNS to inversely calibrate soil hydraulic parameters at the intermediate field scale to simulate the groundwater recharge rates at a daily timescale. The study was conducted for two contrasting hydrological years at the Guaraira experimental basin, Brazil, a 5.84-km(2), a tropical wet and rather flat landscape covered by secondary Atlantic forest. As a consequence of the low altitude and proximity to the equator low neutron count rates could be expected, reducing the precision of CRNS while constituting unexplored and challenging conditions for CRNS applications. Inverse calibration for groundwater recharge rates was used based on CRNS or point-scale soil moisture data. The CRNS-derived retention curve and saturated hydraulic conductivity were consistent with the literature and locally performed slug tests. Simulated groundwater recharge rates ranged from 60 to 470 mm yr(-1), corresponding to 5 and 29% of rainfall, and correlated well with estimates based on water table fluctuations. In contrast, the estimated results based on inversive point-scale datasets were not in alignment with measured water table fluctuations. The better performance of CRNS-based estimations of field-scale hydrological variables, especially groundwater recharge, demonstrated its clear advantages over traditional invasive point-scale techniques. Finally, the study proved the ability of CRNS as practicable in low altitude, tropical wet areas, thus encouraging its adoption for water resources monitoring and management.
Y1 - 2021
U6 - https://doi.org/10.1002/vzj2.20145
SN - 1539-1663
VL - 20
IS - 4
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Durand, Gael
A1 - van den Broeke, Michiel R.
A1 - Le Cozannet, Goneri
A1 - Edwards, Tamsin L.
A1 - Holland, Paul R.
A1 - Jourdain, Nicolas C.
A1 - Marzeion, Ben
A1 - Mottram, Ruth
A1 - Nicholls, Robert J.
A1 - Pattyn, Frank
A1 - Paul, Frank
A1 - Slangen, Aimee B. A.
A1 - Winkelmann, Ricarda
A1 - Burgard, Clara
A1 - van Calcar, Caroline J.
A1 - Barre, Jean-Baptiste
A1 - Bataille, Amelie
A1 - Chapuis, Anne
T1 - Sea-Level rise: from global perspectives to local services
JF - Frontiers in Marine Science
N2 - Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of the two ice sheets, which combined represent a sea-level rise potential of similar to 65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks.
KW - sea-level rise
KW - Antarctic
KW - Greenland
KW - glaciers
KW - local impact
Y1 - 2022
U6 - https://doi.org/10.3389/fmars.2021.709595
SN - 2296-7745
VL - 8
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Zielnica, Krzystof
ED - Ette, Ottmar
ED - Knobloch, Eberhard
T1 - Alexander von Humboldt und Polen – zum 150. Jahrestag seiner Reise nach Warschau
BT - mit einleitenden Worten von Ingo Schwarz
JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies
N2 - Zuerst erschienen in:
Alexander von Humboldt-Stiftung. Mitteilungen, 5. Jg., Heft 38, Oktober 1980, S. 27–36.
KW - Verhältnis zu Polen
KW - Ehrenmitglied der Warschauer Gesellschaft der Freunde der Wissenschaften
KW - Julian Ursyn Niemcewicz
KW - Nikolaus I.
KW - Kaiser von Russland und König von Polen (Kongresspolen)
Y1 - 2024
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-646635
SN - 2568-3543
SN - 1617-5239
VL - XXV
IS - 48
SP - 87
EP - 101
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Pang, Peter Tsun Ho
A1 - Dietrich, Tim
A1 - Tews, Ingo
A1 - Van Den Broeck, Chris
T1 - Parameter estimation for strong phase transitions in supranuclear matter using gravitational-wave astronomy
JF - Physical review research
N2 - At supranuclear densities, explored in the core of neutron stars, a strong phase transition from hadronic matter to more exotic forms of matter might be present. To test this hypothesis, binary neutron-star mergers offer a unique possibility to probe matter at densities that we cannot create in any existing terrestrial experiment. In this work, we show that, if present, strong phase transitions can have a measurable imprint on the binary neutron-star coalescence and the emitted gravitational-wave signal. We construct a new parametrization of the supranuclear equation of state that allows us to test for the existence of a strong phase transition and extract its characteristic properties purely from the gravitational-wave signal of the inspiraling neutron stars. We test our approach using a Bayesian inference study simulating 600 signals with three different equations of state and find that for current gravitational-wave detector networks already 12 events might be sufficient to verify the presence of a strong phase transition. Finally, we use our methodology to analyze GW170817 and GW190425 but do not find any indication that a strong phase transition is present at densities probed during the inspiral.
Y1 - 2020
U6 - https://doi.org/10.1103/PhysRevResearch.2.033514
SN - 2643-1564
VL - 2
IS - 3
PB - American Physical Society
CY - College Park
ER -
TY - JOUR
A1 - Bosch, Sina
A1 - De Cesare, Ilaria
A1 - Demske, Ulrike
A1 - Felser, Claudia
T1 - Word-order variation and coherence in German infinitival complementation
JF - The journal of comparative Germanic linguistics
N2 - This study provides a synthesis of corpus-based and experimental investigations of word-order preferences in German infinitival complementation. We carried out a systematic analysis of present-day German corpora to establish frequency distributions of different word-order options: extraposition, intraposition, and 'third construction'. We then examined, firstly, whether and to what extent corpus frequencies and processing economy constraints can predict the acceptability of these three word-order variants, and whether subject raising and subject control verbs form clearly distinguishable subclasses of infinitive-embedding verbs in terms of their word-order behaviour. Secondly, our study looks into the issue of coherence by comparing acceptability ratings for monoclausal coherent and biclausal incoherent construals of intraposed infinitives, and by examining whether a biclausal incoherent analysis gives rise to local and/or global processing difficulty. Taken together, our results revealed that (i) whilst the extraposition pattern consistently wins out over all other word-order variants for control verbs, neither frequency nor processing-based approaches to word-order variation can account for the acceptability of low-frequency variants, (ii) there is considerable verb-specific variation regarding word-order preferences both between and within the two sets of raising and control verbs under investigation, and (iii) although monoclausal coherent intraposition is rated above biclausal incoherent intraposition, the latter is not any more difficult to process than the former. Our findings indicate that frequency of occurrence and processing-related constraints interact with idiosyncratic lexical properties of individual verbs in determining German speakers' structural preferences.
KW - Syntactic variation
KW - German
KW - Infinitives
KW - Corpus linguistics
KW - Acceptability judgements
KW - Self-paced reading
Y1 - 2023
U6 - https://doi.org/10.1007/s10828-023-09140-8
SN - 1572-8552
VL - 26
IS - 1
PB - Springer
CY - New York
ER -
TY - JOUR
A1 - Tiberius, Victor
A1 - Weyland, Michael
T1 - Improving curricula for higher entrepreneurship education
BT - an international real-time Delphi
JF - Education sciences
N2 - Existing curricula for entrepreneurship education do not necessarily represent the best way of teaching. How could entrepreneurship curricula be improved? To answer this question, we aim to identify and rank desirable teaching objectives, teaching contents, teaching methods, and assessment methods for higher entrepreneurship education. To this end, we employ an international real-time Delphi study with an expert panel consisting of entrepreneurship education instructors and researchers. The study reveals 17 favorable objectives, 17 items of content, 25 teaching methods, and 15 assessment methods, which are ranked according to their desirability and the group consensus. We contribute to entrepreneurship curriculum research by adding a normative perspective.
KW - curriculum design
KW - Delphi study
KW - entrepreneurship education
Y1 - 2024
U6 - https://doi.org/10.3390/educsci14020130
SN - 2227-7102
VL - 14
IS - 2
SP - 1
EP - 17
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Lehmann, Nico
A1 - Kuhn, Yves-Alain
A1 - Keller, Martin
A1 - Aye, Norman
A1 - Herold, Fabian
A1 - Draganski, Bogdan
A1 - Taube, Wolfgang
A1 - Taubert, Marco
T1 - Brain activation during active balancing and its behavioral relevance in younger and older adults
BT - a functional near-infrared spectroscopy (fNIRS) study
JF - Frontiers in Aging Neuroscience
N2 - Age-related deterioration of balance control is widely regarded as an important phenomenon influencing quality of life and longevity, such that a more comprehensive understanding of the neural mechanisms underlying this process is warranted.
Specifically, previous studies have reported that older adults typically show higher neural activity during balancing as compared to younger counterparts, but the implications of this finding on balance performance remain largely unclear.
Using functional near-infrared spectroscopy (fNIRS), differences in the cortical control of balance between healthy younger (n = 27) and older (n = 35) adults were explored.
More specifically, the association between cortical functional activity and balance performance across and within age groups was investigated. To this end, we measured hemodynamic responses (i.e., changes in oxygenated and deoxygenated hemoglobin) while participants balanced on an unstable device.
As criterion variables for brain-behavior-correlations, we also assessed postural sway while standing on a free-swinging platform and while balancing on wobble boards with different levels of difficulty.
We found that older compared to younger participants had higher activity in prefrontal and lower activity in postcentral regions.
Subsequent robust regression analyses revealed that lower prefrontal brain activity was related to improved balance performance across age groups, indicating that higher activity of the prefrontal cortex during balancing reflects neural inefficiency.
We also present evidence supporting that age serves as a moderator in the relationship between brain activity and balance, i.e., cortical hemodynamics generally appears to be a more important predictor of balance performance in the older than in the younger. Strikingly, we found that age differences in balance performance are mediated by balancing-induced activation of the superior frontal gyrus, thus suggesting that differential activation of this region reflects a mechanism involved in the aging process of the neural control of balance.
Our study suggests that differences in functional brain activity between age groups are not a mere by-product of aging, but instead of direct behavioral relevance for balance performance.
Potential implications of these findings in terms of early detection of fall-prone individuals and intervention strategies targeting balance and healthy aging are discussed.
KW - aging
KW - neuroimaging
KW - functional near-infrared spectroscopy (fNIRS)
KW - balance
KW - postural control
KW - prefrontal cortex
KW - neural inefficiency
Y1 - 2022
U6 - https://doi.org/10.3389/fnagi.2022.828474
SN - 1663-4365
VL - 14
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Herold, Fabian
A1 - Labott, Berit K.
A1 - Grässler, Bernhard
A1 - Halfpaap, Nicole
A1 - Langhans, Corinna
A1 - Müller, Patrick
A1 - Ammar, Achraf
A1 - Dordevic, Milos
A1 - Hökelmann, Anita
A1 - Müller, Notger Germar
T1 - A Link between Handgrip Strength and Executive Functioning: A Cross-Sectional Study in Older Adults with Mild Cognitive Impairment and Healthy Controls
JF - Healthcare : open access journal
N2 - Older adults with amnestic mild cognitive impairment (aMCI) who in addition to their memory deficits also suffer from frontal-executive dysfunctions have a higher risk of developing dementia later in their lives than older adults with aMCI without executive deficits and older adults with non-amnestic MCI (naMCI). Handgrip strength (HGS) is also correlated with the risk of cognitive decline in the elderly. Hence, the current study aimed to investigate the associations between HGS and executive functioning in individuals with aMCI, naMCI and healthy controls. Older, right-handed adults with amnestic MCI (aMCI), non-amnestic MCI (naMCI), and healthy controls (HC) conducted a handgrip strength measurement via a handheld dynamometer. Executive functions were assessed with the Trail Making Test (TMT A&B). Normalized handgrip strength (nHGS, normalized to Body Mass Index (BMI)) was calculated and its associations with executive functions (operationalized through z-scores of TMT B/A ratio) were investigated through partial correlation analyses (i.e., accounting for age, sex, and severity of depressive symptoms). A positive and low-to-moderate correlation between right nHGS (rp (22) = 0.364; p = 0.063) and left nHGS (rp (22) = 0.420; p = 0.037) and executive functioning in older adults with aMCI but not in naMCI or HC was observed. Our results suggest that higher levels of nHGS are linked to better executive functioning in aMCI but not naMCI and HC. This relationship is perhaps driven by alterations in the integrity of the hippocampal-prefrontal network occurring in older adults with aMCI. Further research is needed to provide empirical evidence for this assumption.
KW - MCI
KW - hippocampal-prefrontal network
KW - handgrip strength
KW - exercise cognition
KW - aging
KW - brain health
Y1 - 2022
U6 - https://doi.org/10.3390/healthcare10020230
SN - 2227-9032
VL - 10
SP - 1
EP - 14
PB - MDPI
CY - Basel, Schweiz
ET - 2
ER -
TY - JOUR
A1 - Spiegel, Thomas J.
T1 - The Scientific Weltanschauung
BT - (Anti-)Naturalism in Dilthey, Jaspers and Analytic Philosophy
JF - Journal of Transcendental Philosophy
N2 - Different forms of methodological and ontological naturalism constitute the current near-orthodoxy in analytic philosophy. Many prominent figures have called naturalism a (scientific) image (Sellars, W. 1962. “Philosophy and the Scientific Image of Man.” In Wilfrid Sellars, Science, Perception, Reality, 1–40. Ridgeview Publishing), a Weltanschauung (Loewer, B. 2001. “From Physics to Physicalism.” In Physicalism and its Discontents, edited by C. Gillett, and B. Loewer. Cambridge: Cambridge University Press; Stoljar, D. 2010. Physicalism. Routledge), or even a “philosophical ideology” (Kim, J. 2003. “The American Origins of Philosophical Naturalism.” Journal of Philosophical Research 28: 83–98). This suggests that naturalism is indeed something over-and-above an ordinary philosophical thesis (e.g. in contrast to the justified true belief-theory of knowledge). However, these thinkers fail to tease out the host of implications this idea – naturalism being a worldview – presents. This paper draws on (somewhat underappreciated) remarks of Dilthey and Jaspers on the concept of worldviews (Weltanschauung, Weltbild) in order to demonstrate that naturalism as a worldview is a presuppositional background assumption which is left untouched by arguments against naturalism as a thesis. The concluding plea is (in order to make dialectical progress) to re-organize the existing debate on naturalism in a way that treats naturalism not as a first-order philosophical claim, but rather shifts its focus on naturalism’s status as a worldview.
KW - naturalism
KW - ideology
KW - Dilthey
KW - Jaspers
KW - scientific image
KW - worldview
Y1 - 2021
U6 - https://doi.org/10.1515/jtph-2021-0016
SN - 2626-8329
SN - 2626-8310
VL - 2
IS - 2
SP - 259
EP - 276
PB - De Gruyter
CY - Berlin ; Boston
ER -
TY - JOUR
A1 - Uth, Melanie
A1 - Gutiérrez-Bravo, Rodrigo
A1 - Fliessbach, Jan
T1 - On the incompatibility of object fronting and progressive aspect in Yucatec Maya
JF - Frontiers in language sciences
N2 - In this paper, we present data from an elicitation study and a corpus study that support the observation that the Yucatec Maya progressive aspect auxiliary táan is replaced by the habitual auxiliary k in sentences with contrastively focused fronted objects. Focus has been extensively studied in Yucatec, yet the incompatibility of object fronting and progressive aspect in Yucatec Maya remains understudied. Both our experimental results and our corpus study point in the direction that this incompatibility may very well be categorical. Theoretically, we take a progressive reading to be derived from an imperfectivity operator in combination with a singular operator, and we propose that this singular operator implicates the negation of event plurality, leading to an exhaustive interpretation which ranks below corrective focus on a contrastive focus scale. This means that, in a sentence with object focus fronting, the use of the marked auxiliary táan (as opposed to the more general k) would trigger two contrastive foci, which would be an unlikely and probably dispreferred speech act.
KW - fronting
KW - progressive
KW - Yucatec Maya
KW - habitual
KW - focus
Y1 - 2024
U6 - https://doi.org/10.3389/flang.2023.1286520
SN - 2813-4605
VL - 2
PB - Frontiers Media S.A.
CY - Lausanne, Switzerland
ER -
TY - JOUR
A1 - Russell, Eric-John
T1 - Nada es ya lo contrario de nada : la sociedad del espectáculo de Guy Debord hoy
JF - Constelaciones : Revista de Teoría Crítica
T2 - Nothing is any longer the opposite of anything : Guy Debord’s society of the spectacle today
Y1 - 2022
UR - https://constelaciones-rtc.net/article/view/4981
SN - 2172-9506
VL - 14
SP - 426
EP - 434
PB - Departament de Filosofía, Universitat de les Illes Balears
CY - Palma, Spanien
ER -
TY - JOUR
A1 - Pfeifer, Veronika
A1 - Beier, Sönke
A1 - Alirezaeizanjani, Zahra
A1 - Beta, Carsten
T1 - Role of the two flagellar stators in swimming motility of pseudomonas putida
JF - mBio
N2 - In the soil bacterium Pseudomonas putida, the motor torque for flagellar rotation is generated by the two stators MotAB and MotCD.
Here, we construct mutant strains in which one or both stators are knocked out and investigate their swimming motility in fluids of different viscosity and in heterogeneous structured environments (semisolid agar).
Besides phase-contrast imaging of single-cell trajectories and spreading cultures, dual-color fluorescence microscopy allows us to quantify the role of the stators in enabling P. putida's three different swimming modes, where the flagellar bundle pushes, pulls, or wraps around the cell body.
The MotAB stator is essential for swimming motility in liquids, while spreading in semisolid agar is not affected. Moreover, if the MotAB stator is knocked out, wrapped mode formation under low-viscosity conditions is strongly impaired and only partly restored for increased viscosity and in semisolid agar.
In contrast, when the MotCD stator is missing, cells are indistinguishable from the wild type in fluid experiments but spread much more slowly in semisolid agar.
Analysis of the microscopic trajectories reveals that the MotCD knockout strain forms sessile clusters, thereby reducing the number of motile cells, while the swimming speed is unaffected. Together, both stators ensure a robust wild type that swims efficiently under different environmental conditions.
IMPORTANCE
Because of its heterogeneous habitat, the soil bacterium Pseudomonas putida needs to swim efficiently under very different environmental conditions. In this paper, we knocked out the stators MotAB and MotCD to investigate their impact on the swimming motility of P. putida.
While the MotAB stator is crucial for swimming in fluids, in semisolid agar, both stators are sufficient to sustain a fast-swimming phenotype and increased frequencies of the wrapped mode, which is known to be beneficial for escaping mechanical traps. However, in contrast to the MotAB knockout, a culture of MotCD knockout cells spreads much more slowly in the agar, as it forms nonmotile clusters that reduce the number of motile cells.
Because of its heterogeneous habitat, the soil bacterium Pseudomonas putida needs to swim efficiently under very different environmental conditions. In this paper, we knocked out the stators MotAB and MotCD to investigate their impact on the swimming motility of P. putida.
KW - bacterial swimming
KW - stators
KW - structured environments
Y1 - 2022
U6 - https://doi.org/10.1128/mbio.02182-22
SN - 2150-7511
VL - 13
IS - 6
PB - American Society for Microbiology
CY - Washington
ER -
TY - JOUR
A1 - Schell, Mareike
A1 - Wardelmann, Kristina
A1 - Hauffe, Robert
A1 - Rath, Michaela
A1 - Chopra, Simran
A1 - Kleinridders, André
T1 - Lactobacillus rhamnosus sex-specifically attenuates depressive-like behavior and mitigates metabolic consequences in obesity
JF - Biological psychiatry: global open science
N2 - BACKGROUND: Patients with diabetes exhibit an increased prevalence for emotional disorders compared with healthy humans, partially due to a shared pathogenesis including hormone resistance and inflammation, which is also linked to intestinal dysbiosis. The preventive intake of probiotic lactobacilli has been shown to improve dysbiosis along with mood and metabolism. Yet, a potential role of Lactobacillus rhamnosus (Lacticaseibacillus rhamnosus 0030) (LR) in improving emotional behavior in established obesity and the underlying mechanisms are unknown.
METHODS: Female and male C57BL/6N mice were fed a low-fat diet (10% kcal from fat) or high-fat diet (HFD) (45% kcal from fat) for 6 weeks, followed by daily oral gavage of vehicle or 1 3 10 8 colony-forming units of LR, and assessment of anxiety- and depressive-like behavior. Cecal microbiota composition was analyzed using 16S ribosomal RNA sequencing, plasma and cerebrospinal fluid were collected for metabolomic analysis, and gene expression of different brain areas was assessed using reverse transcriptase quantitative polymerase chain reaction.
RESULTS: We observed that 12 weeks of HFD feeding induced hyperinsulinemia, which was attenuated by LR application only in female mice. On the contrary, HFD-fed male mice exhibited increased anxiety- and depressive-like behavior, where the latter was specifically attenuated by LR application, which was independent of metabolic changes. Furthermore, LR application restored the HFD-induced decrease of tyrosine hydroxylase, along with normalizing cholecystokinin gene expression in dopaminergic brain regions; both tyrosine hydroxylase and cholecystokinin are involved in signaling pathways impacting emotional disorders.
CONCLUSIONS: Our data show that LR attenuates depressive-like behavior after established obesity, with changes in the dopaminergic system in male mice, and mitigates hyperinsulinemia in obese female mice.
Y1 - 2023
U6 - https://doi.org/10.1016/j.bpsgos.2023.02.011
SN - 2667-1743
VL - 3
IS - 4
SP - 651
EP - 662
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Markötter, Henning
A1 - Sintschuk, Michael
A1 - Britzke, Ricardo
A1 - Dayani, Shahabeddin
A1 - Bruno, Giovanni
T1 - Upgraded imaging capabilities at the BAMline (BESSY II)
JF - Journal of synchrotron radiation
N2 - The BAMline at the BESSY II synchrotron X-ray source has enabled research for more than 20 years in widely spread research fields such as materials science, biology, cultural heritage and medicine.
As a nondestructive characterization method, synchrotron X-ray imaging, especially tomography, plays a particularly important role in structural characterization.
A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and op erando studies can now be routinely performed, and different energy spectra can easily be set up.
In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired.
The upgraded detector (based on an sCMOS camera) also allows exploiting the higher flux with reduced readout times.
Furthermore, an installed slip ring allows the sample stage to continuously rotate.
The latter feature enables tomographic observation of processes occurring in the time scale of a few seconds.
KW - synchrotron radiation
KW - computed tomography
KW - double-multilayer monochromators
KW - pink beams
KW - X-ray optics
Y1 - 2022
U6 - https://doi.org/10.1107/S1600577522007342
SN - 1600-5775
VL - 29
IS - 5
SP - 1292
EP - 1298
PB - International Union of Crystallography
CY - Chester
ER -
TY - JOUR
A1 - Cestnik, Rok
A1 - Mau, Erik T. K.
A1 - Rosenblum, Michael
T1 - Inferring oscillator's phase and amplitude response from a scalar signal exploiting test stimulation
JF - New journal of physics : the open-access journal for physics
N2 - The phase sensitivity curve or phase response curve (PRC) quantifies the oscillator's reaction to stimulation at a specific phase and is a primary characteristic of a self-sustained oscillatory unit.
Knowledge of this curve yields a phase dynamics description of the oscillator for arbitrary weak forcing. Similar, though much less studied characteristic, is the amplitude response that can be defined either using an ad hoc approach to amplitude estimation or via the isostable variables.
Here, we discuss the problem of the phase and amplitude response inference from observations using test stimulation. Although PRC determination for noise-free neuronal-like oscillators perturbed by narrow pulses is a well-known task, the general case remains a challenging problem. Even more challenging is the inference of the amplitude response. This characteristic is crucial, e.g. for controlling the amplitude of the collective mode in a network of interacting units-a task relevant to neuroscience. Here, we compare the performance of different techniques suitable for inferring the phase and amplitude response, particularly with application to macroscopic oscillators. We suggest improvements to these techniques, e.g. demonstrating how to obtain the PRC in case of stimuli of arbitrary shape. Our main result is a novel technique denoted by IPID-1, based on the direct reconstruction of the Winfree equation and the analogous first-order equation for isostable dynamics. The technique works for signals with or without well-pronounced marker events and pulses of arbitrary shape; in particular, we consider charge-balanced pulses typical in neuroscience applications. Moreover, this technique is superior for noisy and high-dimensional systems. Additionally, we describe an error measure that can be computed solely from data and complements any inference technique.
KW - phase response
KW - amplitude response
KW - phase-isostable reduction
KW - inference
Y1 - 2022
U6 - https://doi.org/10.1088/1367-2630/aca70a
SN - 1367-2630
VL - 24
IS - 12
PB - Dt. Physikalische Ges., IOP
CY - Bad Honnef, London
ER -
TY - JOUR
A1 - Kuhlmann, Sabine
A1 - Franzke, Jochen
A1 - Peters, Niklas
A1 - Dumas, Benoît Paul
T1 - Institutional designs and dynamics of crisis governance at the local level
BT - European governments facing the polycrisis
JF - Policy design and practice
N2 - This article analyses the institutional design variants of local crisis governance responses to the COVID-19 pandemic and their entanglement with other locally impactful crises from a cross-country comparative perspective (France, Germany, Poland, Sweden, and the UK/England). The pandemic offers an excellent empirical lens for scrutinizing the phenomenon of polycrises governance because it occurred while European countries were struggling with the impacts of several prior, ongoing, or newly arrived crises. Our major focus is on institutional design variants of crisis governance (dependent variable) and the influence of different administrative cultures on it (independent variable). Furthermore, we analyze the entanglement and interaction of institutional responses to other (previous or parallel) crises (polycrisis dynamics). Our findings reveal a huge variance of institutional designs, largely evoked by country-specific administrative cultures and profiles. The degree of de-/centralization and the intensity of coordination or decoupling across levels of government differs significantly by country. Simultaneously, all countries were affected by interrelated and entangled crises, resulting in various patterns of polycrisis dynamics. While policy failures and “fatal remedies” from previous crises have partially impaired the resilience and crisis preparedness of local governments, we have also found some learning effects from previous crises.
KW - polycrisis
KW - pandemic
KW - local government
KW - intergovernmental relations
KW - public administration
KW - crisis management
KW - Germany
KW - France
KW - Poland
KW - Sweden
KW - United Kingdom
Y1 - 2024
U6 - https://doi.org/10.1080/25741292.2024.2344784
SN - 2574-1292
SP - 1
EP - 21
PB - Taylor & Francis
CY - London
ER -
TY - JOUR
A1 - Sixtus, Elena
A1 - Lindner, Nadja
A1 - Lohse, Karoline
A1 - Lonnemann, Jan
T1 - Investigating the influence of body movements on children's mental arithmetic performance
JF - Acta psychologica : international journal of psychonomics
N2 - Several lines of research have demonstrated spatial-numerical associations in both adults and children, which are thought to be based on a spatial representation of numerical information in the form of a mental number line. The acquisition of increasingly precise mental number line representations is assumed to support arithmetic learning in children. It is further suggested that sensorimotor experiences shape the development of number concepts and arithmetic learning, and that mental arithmetic can be characterized as “motion along a path” and might constitute shifts in attention along the mental number line. The present study investigated whether movements in physical space influence mental arithmetic in primary school children, and whether the expected effect depends on concurrency of body movements and mental arithmetic. After turning their body towards the left or right, 48 children aged 8 to 10 years solved simple subtraction and addition problems. Meanwhile, they either walked or stood still and looked towards the respective direction. We report a congruency effect between body orientation and operation type, i.e., higher performance for the combinations leftward orientation and subtraction and rightward orientation and addition. We found no significant difference between walking and looking conditions. The present results suggest that mental arithmetic in children is influenced by preceding sensorimotor cues and not necessarily by concurrent body movements.
KW - Mental number line
KW - Horizontal space
KW - Embodied cognition
KW - Arithmetic skills
Y1 - 2023
U6 - https://doi.org/10.1016/j.actpsy.2023.104003
SN - 0001-6918
SN - 1873-6297
VL - 239
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Hermanns, Jolanda
A1 - Kunold, Helen
T1 - Mechanism comics as a task in a written exam in organic chemistry for pre-service chemistry teachers
JF - Chemistry teacher international : best practices in chemistry education
N2 - In this paper, we describe and evaluate a study on the use of mechanism comics for writing solutions to a task in a written exam for the course "Organic Chemistry I for Pre-Service Chemistry Teachers."
The students had to design a reaction mechanism for a reaction that was unknown to them and write captions explaining every step of their reaction mechanism.
The students' work was evaluated using the method of qualitative content analysis in four rounds by both authors. The majority of the captions were coded as "descriptive" and only a minority as "causal."
This means that the students mostly described "what" happened, but seldom "why" this happened. Implicit electron movement was also described more often than explicit electron movement. The majority of the captions were technically correct. In summary, the students were capable of designing and describing a reaction mechanism for a previously unknown reaction.
The quality of their reasoning could be improved, however. In the new course, the quality of students' mechanistic reasoning and then especially their explanations of "why" mechanistic steps occur will be given much clearer emphasis.
KW - concepts
KW - mechanistic reasoning
KW - organic chemistry
KW - pre-service chemistry teachers
KW - writing-to-learn
Y1 - 2022
U6 - https://doi.org/10.1515/cti-2021-0035
SN - 2569-3263
VL - 4
IS - 3
SP - 259
EP - 269
PB - De Gruyter
CY - Berlin
ER -
TY - JOUR
A1 - Ruszkiewicz, Joanna
A1 - Endig, Lisa
A1 - Güver, Ebru
A1 - Bürkle, Alexander
A1 - Mangerich, Aswin
T1 - Life-cycle-dependent toxicities of mono- and bifunctional alkylating agents in the 3R-compliant model organism C. elegans
JF - Cells : open access journal
N2 - Caenorhabditis elegans (C. elegans) is gaining recognition and importance as an organismic model for toxicity testing in line with the 3Rs principle (replace, reduce, refine). In this study, we explored the use of C. elegans to examine the toxicities of alkylating sulphur mustard analogues, specifically the monofunctional agent 2-chloroethyl-ethyl sulphide (CEES) and the bifunctional, crosslinking agent mechlorethamine (HN2). We exposed wild-type worms at different life cycle stages (from larvae L1 to adulthood day 10) to CEES or HN2 and scored their viability 24 h later. The susceptibility of C. elegans to CEES and HN2 paralleled that of human cells, with HN2 exhibiting higher toxicity than CEES, reflected in LC50 values in the high µM to low mM range. Importantly, the effects were dependent on the worms’ developmental stage as well as organismic age: the highest susceptibility was observed in L1, whereas the lowest was observed in L4 worms. In adult worms, susceptibility to alkylating agents increased with advanced age, especially to HN2. To examine reproductive effects, L4 worms were exposed to CEES and HN2, and both the offspring and the percentage of unhatched eggs were assessed. Moreover, germline apoptosis was assessed by using ced-1p::GFP (MD701) worms. In contrast to concentrations that elicited low toxicities to L4 worms, CEES and HN2 were highly toxic to germline cells, manifesting as increased germline apoptosis as well as reduced offspring number and percentage of eggs hatched. Again, HN2 exhibited stronger effects than CEES. Compound specificity was also evident in toxicities to dopaminergic neurons–HN2 exposure affected expression of dopamine transporter DAT-1 (strain BY200) at lower concentrations than CEES, suggesting a higher neurotoxic effect. Mechanistically, nicotinamide adenine dinucleotide (NAD+) has been linked to mustard agent toxicities. Therefore, the NAD+-dependent system was investigated in the response to CEES and HN2 treatment. Overall NAD+ levels in worm extracts were revealed to be largely resistant to mustard exposure except for high concentrations, which lowered the NAD+ levels in L4 worms 24 h post-treatment. Interestingly, however, mutant worms lacking components of NAD+-dependent pathways involved in genome maintenance, namely pme-2, parg-2, and sirt-2.1 showed a higher and compound-specific susceptibility, indicating an active role of NAD+ in genotoxic stress response. In conclusion, the present results demonstrate that C. elegans represents an attractive model to study the toxicology of alkylating agents, which supports its use in mechanistic as well as intervention studies with major strength in the possibility to analyze toxicities at different life cycle stages.
KW - C. elegans
KW - alkylating agents
KW - mustards
KW - life cycle toxicities
KW - neurotoxicity
KW - NAD+
Y1 - 2023
U6 - https://doi.org/10.3390/cells12232728
SN - 2073-4409
VL - 12
IS - 23
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Heyden, Janika
A1 - Natho, Stephanie
T1 - Assessing floodplain management in Germany - a case study on nationwide research and actions
JF - Sustainability
N2 - After a long history of floodplain degradation and substantial losses of inundation areas over the last decades, a rethinking of floodplain management has taken place in Germany.
Floodplains are now acknowledged as important areas for both biodiversity and society. This transformation has been significantly supported by nationwide research activities. A systematic assessment of the current floodplain management is still lacking.
We therefore developed a scheme to assess floodplain management through the steps of identification, analysis, implementation, and evaluation.
Reviewing the data and literature on nationwide floodplain-related research and activities, we defined key elements of floodplain management for Germany.
We concluded that research activities already follow a strategic nationwide approach of identifying and analyzing floodplains.
Progress in implementation is slow, however, and potentials are far from being reached.
Nevertheless, new and unique initiatives enable Germany to stay on the long-term path of giving rivers more space and improving floodplain conditions.
KW - assessment
KW - ecological condition
KW - threatened ecosystem
KW - policy
KW - floodplain restoration
KW - Germany
Y1 - 2022
U6 - https://doi.org/10.3390/su141710610
SN - 2071-1050
VL - 14
IS - 17
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Seyedhosseini, Mehran
T1 - A variant of Roe algebras for spaces with cylindrical ends with applications in relative higher index theory
JF - Journal of noncommutative geometry
N2 - In this paper, we define a variant of Roe algebras for spaces with cylindrical ends and use this to study questions regarding existence and classification of metrics of positive scalar curvature on such manifolds which are collared on the cylindrical end.
We discuss how our constructions are related to relative higher index theory as developed by Chang, Weinberger, and Yu and use this relationship to define higher rho-invariants for positive scalar curvature metrics on manifolds with boundary.
This paves the way for the classification of these metrics.
Finally, we use the machinery developed here to give a concise proof of a result of Schick and the author, which relates the relative higher index with indices defined in the presence of positive scalar curvature on the boundary.
KW - positive scalar curvature
KW - higher index theory
KW - rho-invariants
KW - Roe algebras
KW - manifolds with cylindrical ends
KW - manifolds with boundary
Y1 - 2022
U6 - https://doi.org/10.4171/JNCG/457
SN - 1661-6952
SN - 1661-6960
VL - 16
IS - 2
SP - 595
EP - 624
PB - European Mathematical Society
CY - Zurich
ER -
TY - JOUR
A1 - Heide, Judith
A1 - Netzebandt, Jonka
A1 - Ahrens, Stine
A1 - Brüsch, Julia
A1 - Saalfrank, Teresa
A1 - Schmitz-Antonischki, Dorit
T1 - Improving lexical retrieval with LingoTalk
BT - an app-based, self-administered treatment for clients with aphasia
JF - Frontiers in communication
N2 - Introduction LingoTalk is a German speech-language app designed to enhance lexical retrieval in individuals with aphasia. It incorporates automatic speech recognition (ASR) to provide therapist-independent feedback. The execution and effectiveness of a self-administered intervention with LingoTalk was explored in a case series study.
Methods Three individuals with chronic aphasia participated in a highly individualized, supervised self-administered intervention lasting 3 weeks. The LingoTalk app closely monitored the frequency, intensity and progress of the intervention. Treatment efficacy was assessed using a multiple baseline design, examining both item-specific treatment effects and generalization to untreated items, an untreated task, and spontaneous speech.
Results All participants successfully completed the intervention with LingoTalk, although one participant was not able to use the ASR feature. None of the participants fully adhered to the treatment protocol. All participants demonstrated significant and sustained improvement in the naming of practiced items, although there was limited evidence of generalization. Additionally, there was a slight reduction in word-finding difficulties during spontaneous speech.
Discussion This small-scale study indicates that self-administered intervention with LingoTalk can improve oral naming of treated items. Thus, it has the potential to complement face-to-face speech-language therapy, such as within in a “flipped speech room” approach. The choice of feedback mode is discussed. Transparent progress monitoring of the intervention appears to positively influence patients' motivation.
KW - aphasi
KW - anomia
KW - lexical retrieva
KW - oral naming
KW - app-based intervention
KW - self-training
KW - automatic speech recognition (ASR)
KW - LingoTalk
Y1 - 2023
U6 - https://doi.org/10.3389/fcomm.2023.1210193
SN - 2297-900X
VL - 8
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Rosenblum, Michael
A1 - Pikovsky, Arkady
T1 - Inferring connectivity of an oscillatory network via the phase dynamics reconstruction
JF - Frontiers in network physiology
N2 - We review an approach for reconstructing oscillatory networks’ undirected and directed connectivity from data. The technique relies on inferring the phase dynamics model. The central assumption is that we observe the outputs of all network nodes. We distinguish between two cases. In the first one, the observed signals represent smooth oscillations, while in the second one, the data are pulse-like and can be viewed as point processes. For the first case, we discuss estimating the true phase from a scalar signal, exploiting the protophase-to-phase transformation. With the phases at hand, pairwise and triplet synchronization indices can characterize the undirected connectivity. Next, we demonstrate how to infer the general form of the coupling functions for two or three oscillators and how to use these functions to quantify the directional links. We proceed with a different treatment of networks with more than three nodes. We discuss the difference between the structural and effective phase connectivity that emerges due to high-order terms in the coupling functions. For the second case of point-process data, we use the instants of spikes to infer the phase dynamics model in the Winfree form directly. This way, we obtain the network’s coupling matrix in the first approximation in the coupling strength.
KW - oscillations
KW - network
KW - connectivity
KW - data analysis
KW - phase reduction
Y1 - 2023
U6 - https://doi.org/10.3389/fnetp.2023.1298228
SN - 2674-0109
VL - 3
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Konak, Orhan
A1 - van de Water, Robin
A1 - Döring, Valentin
A1 - Fiedler, Tobias
A1 - Liebe, Lucas
A1 - Masopust, Leander
A1 - Postnov, Kirill
A1 - Sauerwald, Franz
A1 - Treykorn, Felix
A1 - Wischmann, Alexander
A1 - Gjoreski, Hristijan
A1 - Luštrek, Mitja
A1 - Arnrich, Bert
T1 - HARE
BT - unifying the human activity recognition engineering workflow
JF - Sensors
N2 - Sensor-based human activity recognition is becoming ever more prevalent. The increasing importance of distinguishing human movements, particularly in healthcare, coincides with the advent of increasingly compact sensors. A complex sequence of individual steps currently characterizes the activity recognition pipeline. It involves separate data collection, preparation, and processing steps, resulting in a heterogeneous and fragmented process. To address these challenges, we present a comprehensive framework, HARE, which seamlessly integrates all necessary steps. HARE offers synchronized data collection and labeling, integrated pose estimation for data anonymization, a multimodal classification approach, and a novel method for determining optimal sensor placement to enhance classification results. Additionally, our framework incorporates real-time activity recognition with on-device model adaptation capabilities. To validate the effectiveness of our framework, we conducted extensive evaluations using diverse datasets, including our own collected dataset focusing on nursing activities. Our results show that HARE’s multimodal and on-device trained model outperforms conventional single-modal and offline variants. Furthermore, our vision-based approach for optimal sensor placement yields comparable results to the trained model. Our work advances the field of sensor-based human activity recognition by introducing a comprehensive framework that streamlines data collection and classification while offering a novel method for determining optimal sensor placement.
KW - human activity recognition
KW - multimodal classification
KW - privacy preservation
KW - real-time classification
KW - sensor placement
Y1 - 2023
U6 - https://doi.org/10.3390/s23239571
SN - 1424-8220
VL - 23
IS - 23
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Rösler, Antonia
A1 - Gasparatos, Nikolaos
A1 - Hermanussen, Michael
A1 - Scheffler, Christiane
T1 - Practicability and user-friendliness of height measurements by proof of concept APP using Augmented Reality, in 22 healthy children
JF - Human biology and public health
N2 - Background: Child growth is a dynamic process. When measured at short intervals, children’s growth shows characteristic patterns that can be of great importance for clinical purposes.
Objective: To study whether measuring height on a daily basis using an APP is practicable and user-friendly.
Methods: Recruitment took place via Snowball Sampling. Thirteen out of 14 contacted families signed up for a study period of 12 weeks with altogether 22 healthy children aged 3 to 13 years (response rate 93%). The study started with a visit to the family home for the setup of the measurement site, conventional height measuring and initial training of the new measurement process. Follow-up appointments were made at four, eight and 12 weeks. The children’s height was measured at daily intervals at their family homes over a period of three months.
Results: The parents altogether recorded 1704 height measurements and meticulously documented practicability and problems when using the device.
A 93% response rate in recruitment was achieved by maintaining a high motivation within the families. Contact with the principal investigator was permanently available, including open communication, personal training and attendance during the appointments at the family homes.
Conclusion: Measuring height by photographic display is interesting for children and parents and can be used for height measurements at home. A positive response rate of 13 out of 14 families with altogether 22 children highlights feasible recruitment and the high convenience and user-friendliness of daily APP-supported height measurements. Daily APP measurements appear to be a promising new tool for longitudinal growth studies.
KW - body height
KW - guideline
KW - augmented reality
KW - daily home-made measurements
KW - iPhone
KW - APP
Y1 - 2022
U6 - https://doi.org/10.52905/hbph2022.2.48
SN - 2748-9957
VL - 2022
IS - 2
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Brüsch, Julia
A1 - Diener, Antonia
A1 - Hubert, Cilly
A1 - Menze, Clara
A1 - Heide, Judith
T1 - Kneten, blanchieren, dünsten – eine Teletherapie zum mündlichen Verbabruf für Tätigkeiten in der Küche
JF - Spektrum Patholinguistik
Y1 - 2021
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-510362
SN - 978-3-86956-507-1
SN - 1866-9085
SN - 1866-9433
IS - 14
SP - 93
EP - 108
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Schmitz-Antonischki, Dorit
A1 - Heide, Judith
A1 - Netzebandt, Jonka
T1 - Therapie von Wortabrufstörungen mit der App LingoTalk bei einer Patientin mit Aphasie
BT - eine Therapiestudie
JF - Spektrum Patholinguistik 15
Y1 - 2022
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-572433
SN - 978-3-86956-542-2
SN - 1866-9433
SN - 1866-9085
IS - 15
SP - 157
EP - 171
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Kayler, Zachary E.
A1 - Premke, Katrin
A1 - Gessler, Arthur
A1 - Gessner, Mark O.
A1 - Griebler, Christian
A1 - Hilt, Sabine
A1 - Klemedtsson, Leif
A1 - Kuzyakov, Yakov
A1 - Reichstein, Markus
A1 - Siemens, Jan
A1 - Totsche, Kai-Uwe
A1 - Tranvik, Lars
A1 - Wagner, Annekatrin
A1 - Weitere, Markus
A1 - Grossart, Hans-Peter
T1 - Integrating Aquatic and Terrestrial Perspectives to Improve Insights Into Organic Matter Cycling at the Landscape Scale
JF - Frontiers in Earth Science
N2 - Across a landscape, aquatic-terrestrial interfaces within and between ecosystems are hotspots of organic matter (OM) mineralization. These interfaces are characterized by sharp spatio-temporal changes in environmental conditions, which affect OM properties and thus control OM mineralization and other transformation processes. Consequently, the extent of OM movement at and across aquatic-terrestrial interfaces is crucial in determining OM turnover and carbon (C) cycling at the landscape scale. Here, we propose expanding current concepts in aquatic and terrestrial ecosystem sciences to comprehensively evaluate OM turnover at the landscape scale. We focus on three main concepts toward explaining OM turnover at the landscape scale: the landscape spatiotemporal context, OM turnover described by priming and ecological stoichiometry, and anthropogenic effects as a disruptor of natural OM transfer magnitudes and pathways. A conceptual framework is introduced that allows for discussing the disparities in spatial and temporal scales of OM transfer, changes in environmental conditions, ecosystem connectivity, and microbial-substrate interactions. The potential relevance of priming effects in both terrestrial and aquatic systems is addressed. For terrestrial systems, we hypothesize that the interplay between the influx of OM, its corresponding elemental composition, and the elemental demand of the microbial communities may alleviate spatial and metabolic thresholds. In comparison, substrate level OM dynamics may be substantially different in aquatic systems due to matrix effects that accentuate the role of abiotic conditions, substrate quality, and microbial community dynamics. We highlight the disproportionate impact anthropogenic activities can have on OM cycling across the landscape. This includes reversing natural OM flows through the landscape, disrupting ecosystem connectivity, and nutrient additions that cascade across the landscape. This knowledge is crucial for a better understanding of OM cycling in a landscape context, in particular since terrestrial and aquatic compartments may respond differently to the ongoing changes in climate, land use, and other anthropogenic interferences.
KW - landscape connectivity
KW - organic matter mineralization
KW - priming effects
KW - ecological stoichiometry
KW - aquatic-terrestrial interfaces
KW - anthropogenic interferences
Y1 - 2019
U6 - https://doi.org/10.3389/feart.2019.00127
SN - 2296-6463
VL - 7
PB - Frontiers Research Foundation
CY - Lausanne
ER -
TY - JOUR
A1 - Lundgreen, Regitze B. C.
A1 - Jaspers, Cornelia
A1 - Traving, Sachia J.
A1 - Ayala, Daniel J.
A1 - Lombard, Fabien
A1 - Grossart, Hans-Peter
A1 - Nielsen, Torkel G.
A1 - Munk, Peter
A1 - Riemann, Lasse
T1 - Eukaryotic and cyanobacterial communities associated with marine snow particles in the oligotrophic Sargasso Sea
JF - Scientific reports
N2 - Marine snow aggregates represent heterogeneous agglomerates of dead and living organic matter. Composition is decisive for their sinking rates, and thereby for carbon flux to the deep sea. For oligotrophic oceans, information on aggregate composition is particularly sparse. To address this, the taxonomic composition of aggregates collected from the subtropical and oligotrophic Sargasso Sea (Atlantic Ocean) was characterized by 16S and 18S rRNA gene sequencing. Taxonomy assignment was aided by a collection of the contemporary plankton community consisting of 75 morphologically and genetically identified plankton specimens. The diverse rRNA gene reads of marine snow aggregates, not considering Trichodesmium puffs, were dominated by copepods (52%), cnidarians (21%), radiolarians (11%), and alveolates (8%), with sporadic contributions by cyanobacteria, suggesting a different aggregate composition than in eutrophic regions. Composition linked significantly with sampling location but not to any measured environmental parameters or plankton biomass composition. Nevertheless, indicator and network analyses identified key roles of a few rare taxa. This points to complex regulation of aggregate composition, conceivably affected by the environment and plankton characteristics. The extent to which this has implications for particle densities, and consequently for sinking rates and carbon sequestration in oligotrophic waters, needs further interrogation.
Y1 - 2019
U6 - https://doi.org/10.1038/s41598-019-45146-7
SN - 2045-2322
VL - 9
PB - Nature Publ. Group
CY - London
ER -
TY - JOUR
A1 - Numberger, Daniela
A1 - Ganzert, Lars
A1 - Zoccarato, Luca
A1 - Mühldorfer, Kristin
A1 - Sauer, Sascha
A1 - Grossart, Hans-Peter
A1 - Greenwood, Alex D.
T1 - Characterization of bacterial communities in wastewater with enhanced taxonomic resolution by full-length 16S rRNA sequencing
JF - Scientific reports
N2 - Wastewater treatment is crucial to environmental hygiene in urban environments. However, wastewater treatment plants (WWTPs) collect chemicals, organic matter, and microorganisms including pathogens and multi-resistant bacteria from various sources which may be potentially released into the environment via WWTP effluent. To better understand microbial dynamics in WWTPs, we characterized and compared the bacterial community of the inflow and effluent of a WWTP in Berlin, Germany using full-length 16S rRNA gene sequences, which allowed for species level determination in many cases and generally resolved bacterial taxa. Significantly distinct bacterial communities were identified in the wastewater inflow and effluent samples. Dominant operational taxonomic units (OTUs) varied both temporally and spatially. Disease associated bacterial groups were efficiently reduced in their relative abundance from the effluent by the WWTP treatment process, except for Legionella and Leptospira species which demonstrated an increase in relative proportion from inflow to effluent. This indicates that WWTPs, while effective against enteric bacteria, may enrich and release other potentially pathogenic bacteria into the environment. The taxonomic resolution of full-length 16S rRNA genes allows for improved characterization of potential pathogenic taxa and other harmful bacteria which is required to reliably assess health risk.
Y1 - 2019
U6 - https://doi.org/10.1038/s41598-019-46015-z
SN - 2045-2322
VL - 9
PB - Nature Publ. Group
CY - London
ER -
TY - JOUR
A1 - Numberger, Daniela
A1 - Dreier, Carole
A1 - Vullioud, Colin
A1 - Gabriel, Gülsah
A1 - Greenwood, Alex D.
A1 - Grossart, Hans-Peter
T1 - Recovery of influenza a viruses from lake water and sediments by experimental inoculation
JF - PLoS one
N2 - Influenza A viruses (IAV) are zoonotic pathogens relevant to human, domestic animal and wildlife health. Many avian IAVs are transmitted among waterfowl via a faecal-oral-route. Therefore, environmental water where waterfowl congregate may play an important role in the ecology and epidemiology of avian IAV. Water and sediment may sustain and transmit virus among individuals or species. It is unclear at what concentrations waterborne viruses are infectious or remain detectable. To address this, we performed lake water and sediment dilution experiments with varying concentrations or infectious doses of four IAV strains from seal, turkey, duck and gull. To test for infectivity of the IAV strains in a concentration dependent manner, we applied cultivation to specific pathogen free (SPF) embryonated chicken eggs and Madin-Darby Canine Kidney (MDCK) cells. IAV recovery was more effective from embryonated chicken eggs than MDCK cells for freshwater lake dilutions, whereas, MDCK cells were more effective for viral recovery from sediment samples. Low infectious dose (1 PFU/200 mu L) was sufficient in most cases to detect and recover IAV from lake water dilutions. Sediment required higher initial infectious doses (>= 100 PFU/200 mu L).
Y1 - 2019
U6 - https://doi.org/10.1371/journal.pone.0216880
SN - 1932-6203
VL - 14
IS - 5
PB - PLoS
CY - San Fransisco
ER -
TY - JOUR
A1 - Rojas-Jimenez, Keilor
A1 - Grossart, Hans-Peter
A1 - Cordes, Erik
A1 - Cortés, Jorge
T1 - Fungal Communities in Sediments Along a Depth Gradient in the Eastern Tropical Pacific
JF - Frontiers in Microbiology
N2 - Deep waters represent the largest biome on Earth and the largest ecosystem of Costa Rica. Fungi play a fundamental role in global biogeochemical cycling in marine sediments, yet, they remain little explored. We studied fungal diversity and community composition in several marine sediments from 16 locations sampled along a bathymetric gradient (from a depth of 380 to 3,474 m) in two transects of about 1,500 km length in the Eastern Tropical Pacific (ETP) of Costa Rica. Sequence analysis of the V7-V8 region of the 18S rRNA gene obtained from sediment cores revealed the presence of 787 fungal amplicon sequence variants (ASVs). On average, we detected a richness of 75 fungal ASVs per sample. Ascomycota represented the most abundant phylum with Saccharomycetes constituting the dominant class. Three ASVs accounted for ca. 63% of all fungal sequences: the yeast Metschnikowia (49.4%), Rhizophydium (6.9%), and Cladosporium (6.7%). We distinguished a cluster composed mainly by yeasts, and a second cluster by filamentous fungi, but we were unable to detect a strong effect of depth and the overlying water temperature, salinity, dissolved oxygen (DO), and pH on the composition of fungal communities. We highlight the need to understand further the ecological role of fungi in deep-sea ecosystems.
KW - deep-sea
KW - aquatic fungi
KW - biodiversity
KW - Metschnikowia
KW - Costa Rica
Y1 - 2020
U6 - https://doi.org/10.3389/fmicb.2020.575207
SN - 1664-302X
VL - 11
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Tiegs, Scott D.
A1 - Costello, David M.
A1 - Isken, Mark W.
A1 - Woodward, Guy
A1 - McIntyre, Peter B.
A1 - Gessner, Mark O.
A1 - Chauvet, Eric
A1 - Griffiths, Natalie A.
A1 - Flecker, Alex S.
A1 - Acuna, Vicenc
A1 - Albarino, Ricardo
A1 - Allen, Daniel C.
A1 - Alonso, Cecilia
A1 - Andino, Patricio
A1 - Arango, Clay
A1 - Aroviita, Jukka
A1 - Barbosa, Marcus V. M.
A1 - Barmuta, Leon A.
A1 - Baxter, Colden V.
A1 - Bell, Thomas D. C.
A1 - Bellinger, Brent
A1 - Boyero, Luz
A1 - Brown, Lee E.
A1 - Bruder, Andreas
A1 - Bruesewitz, Denise A.
A1 - Burdon, Francis J.
A1 - Callisto, Marcos
A1 - Canhoto, Cristina
A1 - Capps, Krista A.
A1 - Castillo, Maria M.
A1 - Clapcott, Joanne
A1 - Colas, Fanny
A1 - Colon-Gaud, Checo
A1 - Cornut, Julien
A1 - Crespo-Perez, Veronica
A1 - Cross, Wyatt F.
A1 - Culp, Joseph M.
A1 - Danger, Michael
A1 - Dangles, Olivier
A1 - de Eyto, Elvira
A1 - Derry, Alison M.
A1 - Diaz Villanueva, Veronica
A1 - Douglas, Michael M.
A1 - Elosegi, Arturo
A1 - Encalada, Andrea C.
A1 - Entrekin, Sally
A1 - Espinosa, Rodrigo
A1 - Ethaiya, Diana
A1 - Ferreira, Veronica
A1 - Ferriol, Carmen
A1 - Flanagan, Kyla M.
A1 - Fleituch, Tadeusz
A1 - Shah, Jennifer J. Follstad
A1 - Frainer, Andre
A1 - Friberg, Nikolai
A1 - Frost, Paul C.
A1 - Garcia, Erica A.
A1 - Lago, Liliana Garcia
A1 - Garcia Soto, Pavel Ernesto
A1 - Ghate, Sudeep
A1 - Giling, Darren P.
A1 - Gilmer, Alan
A1 - Goncalves, Jose Francisco
A1 - Gonzales, Rosario Karina
A1 - Graca, Manuel A. S.
A1 - Grace, Mike
A1 - Grossart, Hans-Peter
A1 - Guerold, Francois
A1 - Gulis, Vlad
A1 - Hepp, Luiz U.
A1 - Higgins, Scott
A1 - Hishi, Takuo
A1 - Huddart, Joseph
A1 - Hudson, John
A1 - Imberger, Samantha
A1 - Iniguez-Armijos, Carlos
A1 - Iwata, Tomoya
A1 - Janetski, David J.
A1 - Jennings, Eleanor
A1 - Kirkwood, Andrea E.
A1 - Koning, Aaron A.
A1 - Kosten, Sarian
A1 - Kuehn, Kevin A.
A1 - Laudon, Hjalmar
A1 - Leavitt, Peter R.
A1 - Lemes da Silva, Aurea L.
A1 - Leroux, Shawn J.
A1 - Leroy, Carri J.
A1 - Lisi, Peter J.
A1 - MacKenzie, Richard
A1 - Marcarelli, Amy M.
A1 - Masese, Frank O.
A1 - Mckie, Brendan G.
A1 - Oliveira Medeiros, Adriana
A1 - Meissner, Kristian
A1 - Milisa, Marko
A1 - Mishra, Shailendra
A1 - Miyake, Yo
A1 - Moerke, Ashley
A1 - Mombrikotb, Shorok
A1 - Mooney, Rob
A1 - Moulton, Tim
A1 - Muotka, Timo
A1 - Negishi, Junjiro N.
A1 - Neres-Lima, Vinicius
A1 - Nieminen, Mika L.
A1 - Nimptsch, Jorge
A1 - Ondruch, Jakub
A1 - Paavola, Riku
A1 - Pardo, Isabel
A1 - Patrick, Christopher J.
A1 - Peeters, Edwin T. H. M.
A1 - Pozo, Jesus
A1 - Pringle, Catherine
A1 - Prussian, Aaron
A1 - Quenta, Estefania
A1 - Quesada, Antonio
A1 - Reid, Brian
A1 - Richardson, John S.
A1 - Rigosi, Anna
A1 - Rincon, Jose
A1 - Risnoveanu, Geta
A1 - Robinson, Christopher T.
A1 - Rodriguez-Gallego, Lorena
A1 - Royer, Todd V.
A1 - Rusak, James A.
A1 - Santamans, Anna C.
A1 - Selmeczy, Geza B.
A1 - Simiyu, Gelas
A1 - Skuja, Agnija
A1 - Smykla, Jerzy
A1 - Sridhar, Kandikere R.
A1 - Sponseller, Ryan
A1 - Stoler, Aaron
A1 - Swan, Christopher M.
A1 - Szlag, David
A1 - Teixeira-de Mello, Franco
A1 - Tonkin, Jonathan D.
A1 - Uusheimo, Sari
A1 - Veach, Allison M.
A1 - Vilbaste, Sirje
A1 - Vought, Lena B. M.
A1 - Wang, Chiao-Ping
A1 - Webster, Jackson R.
A1 - Wilson, Paul B.
A1 - Woelfl, Stefan
A1 - Xenopoulos, Marguerite A.
A1 - Yates, Adam G.
A1 - Yoshimura, Chihiro
A1 - Yule, Catherine M.
A1 - Zhang, Yixin X.
A1 - Zwart, Jacob A.
T1 - Global patterns and drivers of ecosystem functioning in rivers and riparian zones
JF - Science Advances
N2 - River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.
Y1 - 2019
U6 - https://doi.org/10.1126/sciadv.aav0486
SN - 2375-2548
VL - 5
IS - 1
PB - American Assoc. for the Advancement of Science
CY - Washington
ER -
TY - JOUR
A1 - Wachs, Sebastian
A1 - Wright, Michelle F.
A1 - Sittichai, Ruthaychonnee
A1 - Singh, Ritu
A1 - Biswal, Ramakrishna
A1 - Kim, Eun-mee
A1 - Yang, Soeun
A1 - Gámez-Guadix, Manuel
A1 - Almendros, Carmen
A1 - Flora, Katerina
A1 - Daskalou, Vassiliki
A1 - Maziridou, Evdoxia
T1 - Associations between witnessing and perpetrating online hate in eight countries
BT - the buffering effects of problem-focused coping
JF - International Journal of Environmental Research and Public Health
N2 - Online hate is a topic that has received considerable interest lately, as online hate represents a risk to self-determination and peaceful coexistence in societies around the globe. However, not much is known about the explanations for adolescents posting or forwarding hateful online material or how adolescents cope with this newly emerging online risk. Thus, we sought to better understand the relationship between a bystander to and perpetrator of online hate, and the moderating effects of problem-focused coping strategies (e.g., assertive, technical coping) within this relationship. Self-report questionnaires on witnessing and committing online hate and assertive and technical coping were completed by 6829 adolescents between 12 and 18 years of age from eight countries. The results showed that increases in witnessing online hate were positively related to being a perpetrator of online hate. Assertive and technical coping strategies were negatively related with perpetrating online hate. Bystanders of online hate reported fewer instances of perpetrating online hate when they reported higher levels of assertive and technical coping strategies, and more frequent instances of perpetrating online hate when they reported lower levels of assertive and technical coping strategies. In conclusion, our findings suggest that, if effective, prevention and intervention programs that target online hate should consider educating young people about problem-focused coping strategies, self-assertiveness, and media skills. Implications for future research are discussed.
KW - online hate
KW - hate speech
KW - bystander
KW - perpetrator
KW - coping strategies
KW - cyber aggression
Y1 - 2019
U6 - https://doi.org/10.3390/ijerph16203992
SN - 1660-4601
VL - 16
IS - 20
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Balint, Miklos
A1 - Marton, Orsolya
A1 - Schatz, Marlene
A1 - Düring, Rolf-Alexander
A1 - Grossart, Hans-Peter
T1 - Proper experimental design requires randomization/balancing of molecular ecology experiments
JF - Ecology and evolution
N2 - Properly designed (randomized and/or balanced) experiments are standard in ecological research. Molecular methods are increasingly used in ecology, but studies generally do not report the detailed design of sample processing in the laboratory. This may strongly influence the interpretability of results if the laboratory procedures do not account for the confounding effects of unexpected laboratory events. We demonstrate this with a simple experiment where unexpected differences in laboratory processing of samples would have biased results if randomization in DNA extraction and PCR steps do not provide safeguards. We emphasize the need for proper experimental design and reporting of the laboratory phase of molecular ecology research to ensure the reliability and interpretability of results.
KW - batch effect
KW - bias
KW - DNA extraction
KW - environmental DNA
KW - laboratory practice
KW - lake community
KW - metabarcoding
KW - nondemonic intrusions
KW - PCR
KW - sediment
Y1 - 2018
U6 - https://doi.org/10.1002/ece3.3687
SN - 2045-7758
VL - 8
IS - 3
SP - 1786
EP - 1793
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Bizic-Ionescu, Mina
A1 - Ionescu, Danny
A1 - Grossart, Hans-Peter
T1 - Organic Particles: Heterogeneous Hubs for Microbial Interactions in Aquatic Ecosystems
JF - Frontiers in microbiology
N2 - The dynamics and activities of microbes colonizing organic particles (hereafter particles) greatly determine the efficiency of the aquatic carbon pump. Current understanding is that particle composition, structure and surface properties, determined mostly by the forming organisms and organic matter, dictate initial microbial colonization and the subsequent rapid succession events taking place as organic matter lability and nutrient content change with microbial degradation. We applied a transcriptomic approach to assess the role of stochastic events on initial microbial colonization of particles. Furthermore, we asked whether gene expression corroborates rapid changes in carbon-quality. Commonly used size fractionated filtration averages thousands of particles of different sizes, sources, and ages. To overcome this drawback, we used replicate samples consisting each of 3–4 particles of identical source and age and further evaluated the consequences of averaging 10–1000s of particles. Using flow-through rolling tanks we conducted long-term experiments at near in situ conditions minimizing the biasing effects of closed incubation approaches often referred to as “the bottle-effect.” In our open flow-through rolling tank system, however, active microbial communities were highly heterogeneous despite an identical particle source, suggesting random initial colonization. Contrasting previous reports using closed incubation systems, expression of carbon utilization genes didn’t change after 1 week of incubation. Consequently, we suggest that in nature, changes in particle-associated community related to carbon availability are much slower (days to weeks) due to constant supply of labile, easily degradable organic matter. Initial, random particle colonization seems to be subsequently altered by multiple organismic interactions shaping microbial community interactions and functional dynamics. Comparative analysis of thousands particles pooled togethers as well as pooled samples suggests that mechanistic studies of microbial dynamics should be done on single particles. The observed microbial heterogeneity and inter-organismic interactions may have important implications for evolution and biogeochemistry in aquatic systems.
KW - particle-associated bacteria
KW - microbial communities
KW - inter- and intra-species interactions
KW - antagonism
KW - phage
KW - transcriptome
Y1 - 2018
U6 - https://doi.org/10.3389/fmicb.2018.02569
SN - 1664-302X
VL - 9
PB - Frontiers Research Foundation
CY - Lausanne
ER -
TY - JOUR
A1 - Wurzbacher, Christian
A1 - Fuchs, Andrea
A1 - Attermeyer, Katrin
A1 - Frindte, Katharina
A1 - Grossart, Hans-Peter
A1 - Hupfer, Michael
A1 - Casper, Peter
A1 - Monaghan, Michael T.
T1 - Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment
JF - Microbiome
N2 - Background: Lake sediments harbor diverse microbial communities that cycle carbon and nutrients while being constantly colonized and potentially buried by organic matter sinking from the water column. The interaction of activity and burial remained largely unexplored in aquatic sediments. We aimed to relate taxonomic composition to sediment biogeochemical parameters, test whether community turnover with depth resulted from taxonomic replacement or from richness effects, and to provide a basic model for the vertical community structure in sediments. Methods: We analyzed four replicate sediment cores taken from 30-m depth in oligo-mesotrophic Lake Stechlin in northern Germany. Each 30-cm core spanned ca. 170 years of sediment accumulation according to Cs-137 dating and was sectioned into layers 1-4 cm thick. We examined a full suite of biogeochemical parameters and used DNA metabarcoding to examine community composition of microbial Archaea, Bacteria, and Eukaryota. Results: Community beta-diversity indicated nearly complete turnover within the uppermost 30 cm. We observed a pronounced shift from Eukaryota- and Bacteria-dominated upper layers (<5 cm) to Bacteria-dominated intermediate layers (5-14 cm) and to deep layers (>14 cm) dominated by enigmatic Archaea that typically occur in deep-sea sediments. Taxonomic replacement was the prevalent mechanism in structuring the community composition and was linked to parameters indicative of microbial activity (e.g., CO2 and CH4 concentration, bacterial protein production). Richness loss played a lesser role but was linked to conservative parameters (e.g., C, N, P) indicative of past conditions. Conclusions: By including all three domains, we were able to directly link the exponential decay of eukaryotes with the active sediment microbial community. The dominance of Archaea in deeper layers confirms earlier findings from marine systems and establishes freshwater sediments as a potential low-energy environment, similar to deep sea sediments. We propose a general model of sediment structure and function based on microbial characteristics and burial processes. An upper "replacement horizon" is dominated by rapid taxonomic turnover with depth, high microbial activity, and biotic interactions. A lower "depauperate horizon" is characterized by low taxonomic richness, more stable "low-energy" conditions, and a dominance of enigmatic Archaea.
KW - Archaea
KW - Eukaryota
KW - Bacteria
KW - Community
KW - Freshwater
KW - Lake
KW - DNA metabarcoding
KW - Beta-diversity
KW - Sediment
KW - Turnover
Y1 - 2017
U6 - https://doi.org/10.1186/s40168-017-0255-9
SN - 2049-2618
VL - 5
PB - BioMed Central
CY - London
ER -
TY - JOUR
A1 - Göritz, Anna
A1 - Berger, Stella A.
A1 - Gege, Peter
A1 - Grossart, Hans-Peter
A1 - Nejstgaard, Jens C.
A1 - Riedel, Sebastian
A1 - Röttgers, Rüdiger
A1 - Utschig, Christian
T1 - Retrieval of water constituents from hyperspectral in-situ measurements under variable cloud cover
BT - a case study at Lake Stechlin (Germany)
JF - Remote sensing / Molecular Diversity Preservation International (MDPI)
N2 - Remote sensing and field spectroscopy of natural waters is typically performed under clear skies, low wind speeds and low solar zenith angles. Such measurements can also be made, in principle, under clouds and mixed skies using airborne or in-situ measurements; however, variable illumination conditions pose a challenge to data analysis. In the present case study, we evaluated the inversion of hyperspectral in-situ measurements for water constituent retrieval acquired under variable cloud cover. First, we studied the retrieval of Chlorophyll-a (Chl-a) concentration and colored dissolved organic matter (CDOM) absorption from in-water irradiance measurements. Then, we evaluated the errors in the retrievals of the concentration of total suspended matter (TSM), Chl-a and the absorption coefficient of CDOM from above-water reflectance measurements due to highly variable reflections at the water surface. In order to approximate cloud reflections, we extended a recent three-component surface reflectance model for cloudless atmospheres by a constant offset and compared different surface reflectance correction procedures. Our findings suggest that in-water irradiance measurements may be used for the analysis of absorbing compounds even under highly variable weather conditions. The extended surface reflectance model proved to contribute to the analysis of above-water reflectance measurements with respect to Chl-a and TSM. Results indicate the potential of this approach for all-weather monitoring.
KW - remote sensing
KW - inland water
KW - hyperspectral measurements
KW - in-situ
KW - cloud
KW - surface reflection
KW - inversion
KW - bio-optical modeling
Y1 - 2018
U6 - https://doi.org/10.3390/rs10020181
SN - 2072-4292
VL - 10
IS - 2
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Cuadrat, Rafael R. C.
A1 - Ionescu, Danny
A1 - Davila, Alberto M. R.
A1 - Grossart, Hans-Peter
T1 - Recovering genomics clusters of secondary metabolites from lakes using genome-resolved metagenomics
JF - Frontiers in microbiology
N2 - Metagenomic approaches became increasingly popular in the past decades due to decreasing costs of DNA sequencing and bioinformatics development. So far, however, the recovery of long genes coding for secondary metabolites still represents a big challenge. Often, the quality of metagenome assemblies is poor, especially in environments with a high microbial diversity where sequence coverage is low and complexity of natural communities high. Recently, new and improved algorithms for binning environmental reads and contigs have been developed to overcome such limitations. Some of these algorithms use a similarity detection approach to classify the obtained reads into taxonomical units and to assemble draft genomes. This approach, however, is quite limited since it can classify exclusively sequences similar to those available (and well classified) in the databases. In this work, we used draft genomes from Lake Stechlin, north-eastern Germany, recovered by MetaBat, an efficient binning tool that integrates empirical probabilistic distances of genome abundance, and tetranucleotide frequency for accurate metagenome binning. These genomes were screened for secondary metabolism genes, such as polyketide synthases (PKS) and non-ribosomal peptide synthases (NRPS), using the Anti-SMASH and NAPDOS workflows. With this approach we were able to identify 243 secondary metabolite clusters from 121 genomes recovered from our lake samples. A total of 18 NRPS, 19 PKS, and 3 hybrid PKS/NRPS clusters were found. In addition, it was possible to predict the partial structure of several secondary metabolite clusters allowing for taxonomical classifications and phylogenetic inferences. Our approach revealed a high potential to recover and study secondary metabolites genes from any aquatic ecosystem.
KW - metagenomics 2.0
KW - PKS
KW - NRPS
KW - freshwater
KW - environmental genomics
Y1 - 2018
U6 - https://doi.org/10.3389/fmicb.2018.00251
SN - 1664-302X
VL - 9
PB - Frontiers Research Foundation
CY - Lausanne
ER -