TY - JOUR A1 - Mainka, Stefan A1 - Wissel, Jörg A1 - Völler, Heinz A1 - Evers, Stefan T1 - The Use of Rhythmic Auditory Stimulation to Optimize Treadmill Training for Stroke Patients BT - a randomized controlled trial JF - Frontiers in Neurology N2 - The use of functional music in gait training termed rhythmic auditory stimulation (RAS) and treadmill training (TT) have both been shown to be effective in stroke patients (SP). The combination of RAS and treadmill training (RAS-TT) has not been clinically evaluated to date. The aim of the study was to evaluate the efficacy of RAS-TT on functional gait in SR The protocol followed the design of an explorative study with a rater-blinded three arm prospective randomized controlled parallel group design. Forty-five independently walking SP with a hemiparesis of the lower limb or an unsafe and asymmetrical walking pattern were recruited. RAS-TT was carried out over 4 weeks with TT and neurodevelopmental treatment based on Bobath approach (NDT) serving as control interventions. For RAS-TT functional music was adjusted individually while walking on the treadmill. Pre and post-assessments consisted of the fast gait speed test (FGS), a gait analysis with the locometre (LOC), 3 min walking time test (3MWT), and an instrumental evaluation of balance (IEB). Raters were blinded to group assignments. An analysis of covariance (ANCOVA) was performed with affiliated measures from pre-assessment and time between stroke and start of study as covariates. Thirty-five participants (mean age 63.6 +/- 8.6 years, mean time between stroke and start of study 42.1 +/- 23.7 days) completed the study (11 RAS-TT, 13 TT, 11 NDT). Significant group differences occurred in the FGS for adjusted post-measures in gait velocity [F-(2,F- (34)) = 3.864, p = 0.032; partial eta(2) = 0.205] and cadence [F-(2,F- 34) = 7.656, p = 0.002; partial eta(2) = 0.338]. Group contrasts showed significantly higher values for RAS-TT. Stride length results did not vary between the groups. LOC, 3MWT, and IEB did not indicate group differences. One patient was withdrawn from TT because of pain in one arm. The study provides first evidence for a higher efficacy of RAS-TT in comparison to the standard approaches TT and NDT in restoring functional gait in SP. The results support the implementation of functional music in neurological gait rehabilitation and its use in combination with treadmill training. KW - stroke rehabilitation KW - exercise movement techniques KW - music therapy KW - music KW - gait Y1 - 2018 U6 - https://doi.org/10.3389/fneur.2018.00755 SN - 1664-2295 VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Pauly, Maren A1 - Helle, Gerhard A1 - Miramont, Cecile A1 - Buentgen, Ulf A1 - Treydte, Kerstin A1 - Reinig, Frederick A1 - Guibal, Frederic A1 - Sivan, Olivier A1 - Heinrich, Ingo A1 - Riedel, Frank A1 - Kromer, Bernd A1 - Balanzategui, Daniel A1 - Wacker, Lukas A1 - Sookdeo, Adam A1 - Brauer, Achim T1 - Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas JF - Scientific reports N2 - Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (delta O-18, delta C-13) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (delta O-18(sw)) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (delta O-18(sw)), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low delta O-18(sw)) versus Mediterranean (high delta O-18(sw)) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front. Y1 - 2018 U6 - https://doi.org/10.1038/s41598-018-32251-2 SN - 2045-2322 VL - 8 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Thapa, Samudrajit A1 - Wyłomańska, Agnieszka A1 - Sikora, Grzegorz A1 - Wagner, Caroline E. A1 - Krapf, Diego A1 - Kantz, Holger A1 - Chechkin, Aleksei V. A1 - Metzler, Ralf T1 - Leveraging large-deviation statistics to decipher the stochastic properties of measured trajectories JF - New Journal of Physics N2 - Extensive time-series encoding the position of particles such as viruses, vesicles, or individualproteins are routinely garnered insingle-particle tracking experiments or supercomputing studies.They contain vital clues on how viruses spread or drugs may be delivered in biological cells.Similar time-series are being recorded of stock values in financial markets and of climate data.Such time-series are most typically evaluated in terms of time-averaged mean-squareddisplacements (TAMSDs), which remain random variables for finite measurement times. Theirstatistical properties are different for differentphysical stochastic processes, thus allowing us toextract valuable information on the stochastic process itself. To exploit the full potential of thestatistical information encoded in measured time-series we here propose an easy-to-implementand computationally inexpensive new methodology, based on deviations of the TAMSD from itsensemble average counterpart. Specifically, we use the upper bound of these deviations forBrownian motion (BM) to check the applicability of this approach to simulated and real data sets.By comparing the probability of deviations fordifferent data sets, we demonstrate how thetheoretical bound for BM reveals additional information about observed stochastic processes. Weapply the large-deviation method to data sets of tracer beads tracked in aqueous solution, tracerbeads measured in mucin hydrogels, and of geographic surface temperature anomalies. Ouranalysis shows how the large-deviation properties can be efficiently used as a simple yet effectiveroutine test to reject the BM hypothesis and unveil relevant information on statistical propertiessuch as ergodicity breaking and short-time correlations. KW - diffusion KW - anomalous diffusion KW - large-deviation statistic KW - time-averaged mean squared displacement KW - Chebyshev inequality Y1 - 2020 U6 - https://doi.org/10.1088/1367-2630/abd50e SN - 1367-2630 VL - 23 PB - Dt. Physikalische Ges. ; IOP CY - Bad Honnef ; London ER - TY - JOUR A1 - Berry, Scott A1 - Rosa, Stefanie A1 - Howard, Martin A1 - Buhler, Marc A1 - Dean, Caroline T1 - Disruption of an RNA-binding hinge region abolishes LHP1-mediated epigenetic repression JF - Genes & Development N2 - Epigenetic maintenance of gene repression is essential for development. Polycomb complexes are central to this memory, but many aspects of the underlying mechanism remain unclear. LIKE HETEROCHROMATIN PROTEIN 1 (LHP1) binds Polycomb-deposited H3K27me3 and is required for repression of many Polycomb target genes in Arabidopsis. Here we show that LHP1 binds RNA in vitro through the intrinsically disordered hinge region. By independently perturbing the RNA-binding hinge region and H3K27me3 (trimethylation of histone H3 at Lys27) recognition, we found that both facilitate LHP1 localization and H3K27me3 maintenance. Disruption of the RNAbinding hinge region also prevented formation of subnuclear foci, structures potentially important for epigenetic repression. KW - chromatin KW - epigenetics KW - plant biology KW - Polycomb KW - RNA Y1 - 2017 U6 - https://doi.org/10.1101/gad.305227.117 SN - 0890-9369 SN - 1549-5477 VL - 31 SP - 2115 EP - 2120 PB - Cold Spring Harbor Laboratory Press CY - Cold Spring Harbor, NY ER - TY - JOUR A1 - Huck, Stefan A1 - Wohlwend, Stephan A1 - Coimbra, Rute A1 - Christ, Nicolas A1 - Weissert, Helmut T1 - Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis BT - an in-depth component-specific petrographic and geochemical study from Oman (mid-Cretaceous) JF - The depositional record N2 - Disentangling shallow‐water bulk carbonate carbon isotope archives into primary and diagenetic components is a notoriously difficult task and even diagenetically screened records often provide chemostratigraphic patterns that significantly differ from global signals. This is mainly caused by the polygenetic nature of shallow‐water carbonate substrates, local carbon cycle processes causing considerable neritic–pelagic isotope gradients and the presence of hiatal surfaces resulting in extremely low carbonate preservation rates. Provided here is an in‐depth petrographic and geochemical evaluation of different carbonate phases of a mid‐Cretaceous (Barremian–Aptian) shallow‐water limestone succession (Jabal Madar section) deposited on the tropical Arabian carbonate platform in Oman. The superposition of stable isotope signatures of identified carbonate phases causes a complex and often noisy bulk carbon isotope pattern. Blocky sparite cements filling intergranular pores and bioclastic voids evidence intermediate to (arguably) deep burial diagenetic conditions during their formation, owing to different timing or differential faulting promoting the circulation of fluids from variable sources. In contrast, sparite cements filling sub‐vertical veins reveal a rock‐buffered diagenetic fluid composition with an intriguing moderate enrichment in 13C, probably due to fractionation during pressure release in the context of the Miocene exhumation of the carbonate platform under study. The presence of abundant, replacive dedolomite in mud‐supported limestone samples forced negative carbon and oxygen isotope changes that are either associated with the thermal breakdown of organic matter in the deep burial realm or the expulsion of buried meteoric water in the intermediate burial realm. Notwithstanding the documented stratigraphically variable and often facies‐related impact of different diagenetic fluids on the bulk‐rock stable isotope signature, the identification of diagenetic end‐members defined δ13C and δ18O threshold values that allowed the most reliable ‘primary’ bulk carbon isotope signatures to be extracted. Most importantly, this approach exemplifies how to place regional shallow‐water stable isotope patterns with evidence for a complex multi‐stage diagenetic history into a supraregional or even global context. KW - Arabian carbonate platform KW - Barremian-Aptian KW - multi-stage diagenesis KW - shallow-water chemostratigraphy Y1 - 2017 U6 - https://doi.org/10.1002/dep2.35 SN - 2055-4877 VL - 3 SP - 233 EP - 257 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wendler, Petra A1 - Enenkel, Cordula T1 - Nuclear Transport of Yeast Proteasomes JF - Frontiers in molecular biosciences N2 - Proteasomes are key proteases in regulating protein homeostasis. Their holo-enzymes are composed of 40 different subunits which are arranged in a proteolytic core (CP) flanked by one to two regulatory particles (RP). Proteasomal proteolysis is essential for the degradation of proteins which control time-sensitive processes like cell cycle progression and stress response. In dividing yeast and human cells, proteasomes are primarily nuclear suggesting that proteasomal proteolysis is mainly required in the nucleus during cell proliferation. In yeast, which have a closed mitosis, proteasomes are imported into the nucleus as immature precursors via the classical import pathway. During quiescence, the reversible absence of proliferation induced by nutrient depletion or growth factor deprivation, proteasomes move from the nucleus into the cytoplasm. In the cytoplasm of quiescent yeast, proteasomes are dissociated into CP and RP and stored in membrane-less cytoplasmic foci, named proteasome storage granules (PSGs). With the resumption of growth, PSGs clear and mature proteasomes are transported into the nucleus by Blm10, a conserved 240 kDa protein and proteasome-intrinsic import receptor. How proteasomes are exported from the nucleus into the cytoplasm is unknown. KW - proteasome KW - nuclear transport KW - importin KW - karyopherin KW - Blm10 KW - proteasome storage granules Y1 - 2019 U6 - https://doi.org/10.3389/fmolb.2019.00034 SN - 2296-889X VL - 6 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Möser, Christin A1 - Lorenz, Jessica S. A1 - Sajfutdinow, Martin A1 - Smith, David M. T1 - Pinpointed Stimulation of EphA2 Receptors via DNA-Templated Oligovalence JF - International journal of molecular sciences N2 - DNA nanostructures enable the attachment of functional molecules to nearly any unique location on their underlying structure. Due to their single-base-pair structural resolution, several ligands can be spatially arranged and closely controlled according to the geometry of their desired target, resulting in optimized binding and/or signaling interactions. Here, the efficacy of SWL, an ephrin-mimicking peptide that binds specifically to EphrinA2 (EphA2) receptors, increased by presenting up to three of these peptides on small DNA nanostructures in an oligovalent manner. Ephrin signaling pathways play crucial roles in tumor development and progression. Moreover, Eph receptors are potential targets in cancer diagnosis and treatment. Here, the quantitative impact of SWL valency on binding, phosphorylation (key player for activation) and phenotype regulation in EphA2-expressing prostate cancer cells was demonstrated. EphA2 phosphorylation was significantly increased by DNA trimers carrying three SWL peptides compared to monovalent SWL. In comparison to one of EphA2’s natural ligands ephrin-A1, which is known to bind promiscuously to multiple receptors, pinpointed targeting of EphA2 by oligovalent DNA-SWL constructs showed enhanced cell retraction. Overall, we show that DNA scaffolds can increase the potency of weak signaling peptides through oligovalent presentation and serve as potential tools for examination of complex signaling pathways. KW - DNA nanostructure KW - ephrin KW - EphA2 KW - SWL KW - PC-3 cells KW - multivalence Y1 - 2018 U6 - https://doi.org/10.3390/ijms19113482 SN - 1422-0067 VL - 19 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schwanhold, Nadine A1 - Iobbi-Nivol, Chantal A1 - Lehmann, Angelika A1 - Leimkühler, Silke T1 - Same but different BT - Comparison of two system-specific molecular chaperones for the maturation of formate dehydrogenases JF - PLoS one N2 - The maturation of bacterial molybdoenzymes is a complex process leading to the insertion of the bulky bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor into the apoenzyme. Most molybdoenzymes were shown to contain a specific chaperone for the insertion of the bis-MGD cofactor. Formate dehydrogenases (FDH) together with their molecular chaperone partner seem to display an exception to this specificity rule, since the chaperone FdhD has been proven to be involved in the maturation of all three FDH enzymes present in Escherichia colt. Multiple roles have been suggested for FdhD-like chaperones in the past, including the involvement in a sulfur transfer reaction from the L-cysteine desulfurase IscS to bis-MGD by the action of two cysteine residues present in a conserved CXXC motif of the chaperones. However, in this study we show by phylogenetic analyses that the CXXC motif is not conserved among FdhD-like chaperones. We compared in detail the FdhD-like homologues from Rhodobacter capsulatus and E. colt and show that their roles in the maturation of FDH enzymes from different subgroups can be exchanged. We reveal that bis-MGDbinding is a common characteristic of FdhD-like proteins and that the cofactor is bound with a sulfido-ligand at the molybdenum atom to the chaperone. Generally, we reveal that the cysteine residues in the motif CXXC of the chaperone are not essential for the production of active FDH enzymes. Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0201935 SN - 1932-6203 VL - 13 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Siddiqui, Tarique Adnan A1 - Maute, Astrid A1 - Pedatella, Nick A1 - Yamazaki, Yosuke A1 - Lühr, Hermann A1 - Stolle, Claudia T1 - On the variability of the semidiurnal solar and lunar tides of the equatorial electrojet during sudden stratospheric warmings JF - Annales geophysicae N2 - The variabilities of the semidiurnal solar and lunar tides of the equatorial electrojet (EEJ) are investigated during the 2003, 2006, 2009 and 2013 major sudden stratospheric warming (SSW) events in this study. For this purpose, ground-magnetometer recordings at the equatorial observatories in Huancayo and Fuquene are utilized. Results show a major enhancement in the amplitude of the EEJ semidiurnal lunar tide in each of the four warming events. The EEJ semidiurnal solar tidal amplitude shows an amplification prior to the onset of warmings, a reduction during the deceleration of the zonal mean zonal wind at 60 degrees N and 10 hPa, and a second enhancement a few days after the peak reversal of the zonal mean zonal wind during all four SSWs. Results also reveal that the amplitude of the EEJ semidiurnal lunar tide becomes comparable or even greater than the amplitude of the EEJ semidiurnal solar tide during all these warming events. The present study also compares the EEJ semidiurnal solar and lunar tidal changes with the variability of the migrating semidiurnal solar (SW2) and lunar (M2) tides in neutral temperature and zonal wind obtained from numerical simulations at E-region heights. A better agreement between the enhancements of the EEJ semidiurnal lunar tide and the M2 tide is found in comparison with the enhancements of the EEJ semidiurnal solar tide and the SW2 tide in both the neutral temperature and zonal wind at the E-region altitudes. Y1 - 2018 U6 - https://doi.org/10.5194/angeo-36-1545-2018 SN - 0992-7689 SN - 1432-0576 VL - 36 IS - 6 SP - 1545 EP - 1562 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Rosenbaum, Benjamin A1 - Raatz, Michael A1 - Weithoff, Guntram A1 - Fussmann, Gregor F. A1 - Gaedke, Ursula T1 - Estimating parameters from multiple time series of population dynamics using bayesian inference JF - Frontiers in ecology and evolution N2 - Empirical time series of interacting entities, e.g., species abundances, are highly useful to study ecological mechanisms. Mathematical models are valuable tools to further elucidate those mechanisms and underlying processes. However, obtaining an agreement between model predictions and experimental observations remains a demanding task. As models always abstract from reality one parameter often summarizes several properties. Parameter measurements are performed in additional experiments independent of the ones delivering the time series. Transferring these parameter values to different settings may result in incorrect parametrizations. On top of that, the properties of organisms and thus the respective parameter values may vary considerably. These issues limit the use of a priori model parametrizations. In this study, we present a method suited for a direct estimation of model parameters and their variability from experimental time series data. We combine numerical simulations of a continuous-time dynamical population model with Bayesian inference, using a hierarchical framework that allows for variability of individual parameters. The method is applied to a comprehensive set of time series from a laboratory predator-prey system that features both steady states and cyclic population dynamics. Our model predictions are able to reproduce both steady states and cyclic dynamics of the data. Additionally to the direct estimates of the parameter values, the Bayesian approach also provides their uncertainties. We found that fitting cyclic population dynamics, which contain more information on the process rates than steady states, yields more precise parameter estimates. We detected significant variability among parameters of different time series and identified the variation in the maximum growth rate of the prey as a source for the transition from steady states to cyclic dynamics. By lending more flexibility to the model, our approach facilitates parametrizations and shows more easily which patterns in time series can be explained also by simple models. Applying Bayesian inference and dynamical population models in conjunction may help to quantify the profound variability in organismal properties in nature. KW - Bayesian inference KW - chemostat experiments KW - ordinary differential equation KW - parameter estimation KW - population dynamics KW - predator prey KW - time series analysis KW - trait variability Y1 - 2019 U6 - https://doi.org/10.3389/fevo.2018.00234 SN - 2296-701X VL - 6 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Kruse, Julia A1 - Kummer, Volker A1 - Shivas, Roger G. A1 - Thines, Marco T1 - The first smut fungus, Thecaphora anthemidis sp nov (Glomosporiaceae), described from Anthemis (Asteraceae) JF - MycoKeys N2 - There are 63 known species of Thecaphora (Glomosporiaceae, Ustilaginomycotina), a third of which occur on Asteraceae. These smut fungi produce yellowish-brown to reddish-brown masses of spore balls in specific, mostly regenerative, plant organs. A species of Thecaphora was collected in the flower heads of Anthemis chia (Anthemideae, Asteraceae) on Rhodes Island, Greece, in 2015 and 2017, which represents the first smut record of a smut fungus on a host plant species in this tribe. Based on its distinctive morphology, host species and genetic divergence, this species is described as Thecaphora anthemidis sp. nov. Molecular barcodes of the ITS region are provided for this and several other species of Thecaphora. A phylogenetic and morphological comparison to closely related species showed that Th. anthemidis differed from other species of Thecaphora. Thecaphora anthemidis produced loose spore balls in the flower heads and peduncles of Anthemis chia unlike other flower-infecting species. KW - Glomosporiaceae KW - host specificity KW - internal transcribed spacer KW - molecular phylogenetics KW - smut fungi Y1 - 2018 U6 - https://doi.org/10.3897/mycokeys.41.28454 SN - 1314-4057 SN - 1314-4049 IS - 41 SP - 39 EP - 50 PB - Pensoft Publ. CY - Sofia ER - TY - JOUR A1 - Manzoni, Stefano A1 - Capek, Petr A1 - Porada, Philipp A1 - Thurner, Martin A1 - Winterdahl, Mattias A1 - Beer, Christian A1 - Bruchert, Volker A1 - Frouz, Jan A1 - Herrmann, Anke M. A1 - Lindahl, Bjorn D. A1 - Lyon, Steve W. A1 - Šantrůčková, Hana A1 - Vico, Giulia A1 - Way, Danielle T1 - Reviews and syntheses BT - Carbon use efficiency from organisms to ecosystems - definitions, theories, and empirical evidence JF - Biogeosciences N2 - The cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) - the ratio of C remaining in a system to C entering that system. Biological CUE is the fraction of C taken up allocated to biosynthesis. In soils and sediments, C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems and watersheds, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns; for example, the actual CUE increases with improving growth conditions, and apparent CUE decreases with increasing turnover. We then synthesize > 5000CUE estimates showing that CUE decreases with increasing biological and ecological organization - from uni-cellular to multicellular organisms and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C. Y1 - 2018 U6 - https://doi.org/10.5194/bg-15-5929-2018 SN - 1726-4170 SN - 1726-4189 VL - 15 IS - 19 SP - 5929 EP - 5949 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Risbey, James S. A1 - Lewandowsky, Stephan A1 - Cowtan, Kevin A1 - Oreskes, Naomi A1 - Rahmstorf, Stefan A1 - Jokimäki, Ari A1 - Foster, Grant T1 - A fluctuation in surface temperature in historical context BT - reassessment and retrospective on the evidence JF - Environmental research letters N2 - This work reviews the literature on an alleged global warming 'pause' in global mean surface temperature (GMST) to determine how it has been defined, what time intervals are used to characterise it, what data are used to measure it, and what methods used to assess it. We test for 'pauses', both in the normally understood meaning of the term to mean no warming trend, as well as for a 'pause' defined as a substantially slower trend in GMST. The tests are carried out with the historical versions of GMST that existed for each pause-interval tested, and with current versions of each of the GMST datasets. The tests are conducted following the common (but questionable) practice of breaking the linear fit at the start of the trend interval ('broken' trends), and also with trends that are continuous with the data bordering the trend interval. We also compare results when appropriate allowance is made for the selection bias problem. The results show that there is little or no statistical evidence for a lack of trend or slower trend in GMST using either the historical data or the current data. The perception that there was a 'pause' in GMST was bolstered by earlier biases in the data in combination with incomplete statistical testing. KW - climate variability KW - climate trends KW - temperature fluctuation KW - pause hiatus Y1 - 2018 U6 - https://doi.org/10.1088/1748-9326/aaf342 SN - 1748-9326 VL - 13 IS - 12 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Perkins, Daniel M. A1 - Perna, Andrea A1 - Adrian, Rita A1 - Cermeno, Pedro A1 - Gaedke, Ursula A1 - Huete-Ortega, Maria A1 - White, Ethan P. A1 - Yvon-Durocher, Gabriel T1 - Energetic equivalence underpins the size structure of tree and phytoplankton communities JF - Nature Communications N2 - The size structure of autotroph communities - the relative abundance of small vs. large individuals - shapes the functioning of ecosystems. Whether common mechanisms underpin the size structure of unicellular and multicellular autotrophs is, however, unknown. Using a global data compilation, we show that individual body masses in tree and phytoplankton communities follow power-law distributions and that the average exponents of these individual size distributions (ISD) differ. Phytoplankton communities are characterized by an average ISD exponent consistent with three-quarter-power scaling of metabolism with body mass and equivalence in energy use among mass classes. Tree communities deviate from this pattern in a manner consistent with equivalence in energy use among diameter size classes. Our findings suggest that whilst universal metabolic constraints ultimately underlie the emergent size structure of autotroph communities, divergent aspects of body size (volumetric vs. linear dimensions) shape the ecological outcome of metabolic scaling in forest vs. pelagic ecosystems. Y1 - 2019 U6 - https://doi.org/10.1038/s41467-018-08039-3 SN - 2041-1723 VL - 10 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Wickert, Andrew D. A1 - Schildgen, Taylor F. T1 - Long-profile evolution of transport-limited gravel-bed rivers JF - Earth surface dynamics N2 - Alluvial and transport-limited bedrock rivers constitute the majority of fluvial systems on Earth. Their long profiles hold clues to their present state and past evolution. We currently possess first-principles-based governing equations for flow, sediment transport, and channel morphodynamics in these systems, which we lack for detachment-limited bedrock rivers. Here we formally couple these equations for transport-limited gravel-bed river long-profile evolution. The result is a new predictive relationship whose functional form and parameters are grounded in theory and defined through experimental data. From this, we produce a power-law analytical solution and a finite-difference numerical solution to long-profile evolution. Steady-state channel concavity and steepness are diagnostic of external drivers: concavity decreases with increasing uplift rate, and steepness increases with an increasing sediment-to-water supply ratio. Constraining free parameters explains common observations of river form: to match observed channel concavities, gravel-sized sediments must weather and fine - typically rapidly - and valleys typically should widen gradually. To match the empirical square-root width-discharge scaling in equilibrium-width gravel-bed rivers, downstream fining must occur. The ability to assign a cause to such observations is the direct result of a deductive approach to developing equations for landscape evolution. Y1 - 2019 U6 - https://doi.org/10.5194/esurf-7-17-2019 SN - 2196-6311 SN - 2196-632X VL - 7 IS - 1 SP - 17 EP - 43 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Uber, Magdalena A1 - Vandervaere, Jean-Pierre A1 - Zin, Isabella A1 - Braud, Isabelle A1 - Heistermann, Maik A1 - Legout, Cedric A1 - Molinie, Gilles A1 - Nord, Guillaume T1 - How does initial soil moisture influence the hydrological response? A case study from southern France JF - Hydrology and earth system sciences : HESS N2 - The phi(ev) is calculated from high-resolution discharge and precipitation data for several rain events with a cumulative precipitation P-cum ranging from less than 5mm to more than 80 mm. Because of the high uncertainty of phi(ev) associated with the hydrograph separation method, phi(ev) is calculated with several methods, including graphical methods, digital filters and a tracer-based method. The results indicate that the hydrological response depends on (theta) over bar (ini): during dry conditions phi(ev) is consistently below 0.1, even for events with high and intense precipitation. Above a threshold of (theta) over bar (ini) = 34 vol % phi(ev) can reach values up to 0.99 but there is a high scatter. Some variability can be explained with a weak correlation of phi(ev) with P-cum and rain intensity, but a considerable part of the variability remains unexplained. It is concluded that threshold-based methods can be helpful to prevent overestimation of the hydrological response during dry catchment conditions. The impact of soil moisture on the hydrological response during wet catchment conditions, however, is still insufficiently understood and cannot be generalized based on the present results. Y1 - 2018 U6 - https://doi.org/10.5194/hess-22-6127-2018 SN - 1027-5606 SN - 1607-7938 VL - 22 IS - 12 SP - 6127 EP - 6146 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Milewski, Robert A1 - Chabrillat, Sabine A1 - Behling, Robert T1 - Analyses of Recent Sediment Surface Dynamic of a Namibian Kalahari Salt Pan Based on Multitemporal Landsat and Hyperspectral Hyperion Data JF - Remote Sensing N2 - This study combines spaceborne multitemporal and hyperspectral data to analyze the spatial distribution of surface evaporite minerals and changes in a semi-arid depositional environment associated with episodic flooding events, the Omongwa salt pan (Kalahari, Namibia). The dynamic of the surface crust is evaluated by a change-detection approach using the Iterative-reweighted Multivariate Alteration Detection (IR-MAD) based on the Landsat archive imagery from 1984 to 2015. The results show that the salt pan is a highly dynamic and heterogeneous landform. A change gradient is observed from very stable pan border to a highly dynamic central pan. On the basis of hyperspectral EO-1 Hyperion images, the current distribution of surface evaporite minerals is characterized using Spectral Mixture Analysis (SMA). Assessment of field and image endmembers revealed that the pan surface can be categorized into three major crust types based on diagnostic absorption features and mineralogical ground truth data. The mineralogical crust types are related to different zones of surface change as well as pan morphology that influences brine flow during the pan inundation and desiccation cycles. These combined information are used to spatially map depositional environments where the more dynamic halite crust concentrates in lower areas although stable gypsum and calcite/sepiolite crusts appear in higher elevated areas. KW - salt pan KW - playa KW - hyperspectral KW - multitemporal KW - change detection KW - evaporite minerals Y1 - 2016 U6 - https://doi.org/10.3390/rs9020170 SN - 2072-4292 VL - 9 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schinköth, Michaela A1 - Brand, Ralf T1 - Automatic associations and the affective valuation of exercise BT - disentangling the type-1 process of the affective–reflective theory of physical inactivity and exercise JF - German Journal of Exercise and Sport Research N2 - The decision to exercise is not only bound to rational considerations but also automatic affective processes. The affective–reflective theory of physical inactivity and exercise (ART) proposes a theoretical framework for explaining how the automatic affective process (type‑1 process) will influence exercise behavior, i.e., through the automatic activation of exercise-related associations and a subsequent affective valuation of exercise. This study aimed to empirically test this assumption of the ART with data from 69 study participants. A single-measurement study, including within-subject experimental variation, was conducted. Automatic associations with exercise were first measured with a single-target implicit association test. The somato-affective core of the participants’ automatic valuation of exercise-related pictures was then assessed via heart rate variability (HRV) analysis, and the affective valence of the valuation was tested with a facial expression (FE; smile and frown) task. Exercise behavior was assessed via self-report. Multiple regression (path) analysis revealed that automatic associations predicted HRV reactivity (β = −0.24, p = .044); the signs of the correlation between automatic associations and the smile FE score was in the expected direction but remained nonsignificant (β = −0.21, p = .078). HRV reactivity predicted self-reported exercise behavior (β = −0.28, p = .013) (the same pattern of results was achieved for the frown FE score). The HRV-related results illustrate the potential role of automatic negative affective reactions to the thought of exercise as a restraining force in exercise motivation. For better empirical distinction between the two ART type‑1 process components, automatic associations and the affective valuation should perhaps be measured separately in the future. The results support the notion that automatic and affective processes should be regarded as essential aspects of the motivation to exercise. KW - Heart rate variability KW - Facial expression KW - Somatic KW - Dual-process KW - Motivation Y1 - 2019 U6 - https://doi.org/10.1007/s12662-020-00664-9 SN - 2509-3150 SN - 2509-3142 VL - 50 IS - 654 SP - 366 EP - 376 PB - Springer CY - Berlin ; Heidelberg ER - TY - JOUR A1 - Mardoukhi, Yousof A1 - Chechkin, Aleksei V. A1 - Metzler, Ralf T1 - Spurious ergodicity breaking in normal and fractional Ornstein–Uhlenbeck process JF - New Journal of Physics N2 - The Ornstein–Uhlenbeck process is a stationary and ergodic Gaussian process, that is fully determined by its covariance function and mean. We show here that the generic definitions of the ensemble- and time-averaged mean squared displacements fail to capture these properties consistently, leading to a spurious ergodicity breaking. We propose to remedy this failure by redefining the mean squared displacements such that they reflect unambiguously the statistical properties of any stochastic process. In particular we study the effect of the initial condition in the Ornstein–Uhlenbeck process and its fractional extension. For the fractional Ornstein–Uhlenbeck process representing typical experimental situations in crowded environments such as living biological cells, we show that the stationarity of the process delicately depends on the initial condition. KW - Ornstein–Uhlenbeck process KW - stationary stochastic process KW - ensemble and time averaged mean squared displacement Y1 - 2020 U6 - https://doi.org/10.1088/1367-2630/ab950b SN - 1367-2630 VL - 22 PB - IOP CY - London ER - TY - JOUR A1 - Lonsdorf, Tina B. A1 - Klingelhöfer-Jens, Maren A1 - Andreatta, Marta A1 - Beckers, Tom A1 - Chalkia, Anastasia A1 - Gerlicher, Anna A1 - Jentsch, Valerie L. A1 - Drexler, Shira Meir A1 - Mertens, Gaetan A1 - Richter, Jan A1 - Sjouwerman, Rachel A1 - Wendt, Julia A1 - Merz, Christian J. T1 - Navigating the garden of forking paths for data exclusions in fear conditioning research JF - eLife N2 - In this report, we illustrate the considerable impact of researcher degrees of freedom with respect to exclusion of participants in paradigms with a learning element. We illustrate this empirically through case examples from human fear conditioning research, in which the exclusion of ‘non-learners’ and ‘non-responders’ is common – despite a lack of consensus on how to define these groups. We illustrate the substantial heterogeneity in exclusion criteria identified in a systematic literature search and highlight the potential problems and pitfalls of different definitions through case examples based on re-analyses of existing data sets. On the basis of these studies, we propose a consensus on evidence-based rather than idiosyncratic criteria, including clear guidelines on reporting details. Taken together, we illustrate how flexibility in data collection and analysis can be avoided, which will benefit the robustness and replicability of research findings and can be expected to be applicable to other fields of research that involve a learning element. Y1 - 2019 U6 - https://doi.org/10.7554/eLife.52465 SN - 2050-084X VL - 8 PB - eLife Sciences Publications CY - Cambridge ER -