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Molecular Basis for Ser/Thr Specificity in PKA Signaling
(2020-06-25)
cAMP-dependent protein kinase (PKA) is the major receptor of the second messenger cAMP and a prototype for Ser/Thr-specific protein kinases. Although PKA strongly prefers serine over threonine substrates, little is known about the molecular basis of this substrate specificity. We employ classical enzyme kinetics and a surface plasmon resonance (SPR)-based method to analyze each step of the kinase reaction. In the absence of divalent metal ions and nucleotides, PKA binds serine (PKS) and threonine (PKT) substrates, ...
Aufsatz
Disentangling the complexity of socio-cultural values of temporary rivers
(2021-05-20)
In the last decade, an awareness towards temporary rivers has increased globally in response to drying climates and growing human demand for water. However, social perceptions of temporary rivers have rarely been incorporated in their science and management. In this study, we advance an understanding of the socio-cultural values of temporary rivers principally in a European context. We used an ecosystem services-based approach for a participatory and deliberative exercise with 16 researchers and managers. Our results ...
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Sphaeropsis sapinea and fungal endophyte diversity in twigs of Scots pine (Pinus sylvestris) in Germany
(2020-09-03)
Sphaeropsis sapinea is the causal fungal agent of Diplodia tip blight disease of Scots pine (Pinus sylvestris) and other coniferous trees of relevance to forestry in Germany. In this study, the distribution and occurrence of S. sapinea and accompanying endophytic fungi in twigs of healthy and diseased Scots pine was investigated on a spatial and temporal scale. Sampling of 26,000 twig segments from trees in 105 temperate coniferous forest stands in Germany resulted in isolation of 33,000 endophytic fungi consisting ...
Aufsatz
Introducing the Logarithmic finite element method: a geometrically exact planar Bernoulli beam element
(2016-09-15)
We propose a novel finite element formulation that significantly reduces the number of degrees of freedom necessary to obtain reasonably accurate approximations of the low-frequency component of the deformation in boundary-value problems. In contrast to the standard Ritz–Galerkin approach, the shape functions are defined on a Lie algebra—the logarithmic space—of the deformation function. We construct a deformation function based on an interpolation of transformations at the nodes of the finite element. In the case ...
Aufsatz
Assessing spatial variability of barley whole crop biomass yield and leaf area index in silvoarable agroforestry systems using UAV-borne remote sensing
(2021-07-13)
Agroforestry systems (AFS) can provide positive ecosystem services while at the same time stabilizing yields under increasingly common drought conditions. The effect of distance to trees in alley cropping AFS on yield-related crop parameters has predominantly been studied using point data from transects. Unmanned aerial vehicles (UAVs) offer a novel possibility to map plant traits with high spatial resolution and coverage. In the present study, UAV-borne red, green, blue (RGB) and multispectral imagery was utilized ...
Aufsatz
Soil Gaseous Emissions and Partial C and N Balances of Small-Scale Farmer Fields in a River Oasis of Western Mongolia
(2019-06-18)
During the last decades, Mongolian river oases were subjected to an expansion of farmland. Such intensification triggers substantial gaseous carbon (C) and nitrogen (N) losses that may aggravate disequilibria in the soil surface balances of agricultural plots. This study aims to quantify such losses, and assess the implications of these emissions against the background of calculated partial C and N balances. To this end, CO2, NH3, and N2O soil emissions from carrot, hay, and rye plots were measured by a portable ...
Aufsatz
Photon–electron coincidence experiments at synchrotron radiation facilities with arbitrary bunch modes
(2021-04-21)
We report the adaptation of an electron–photon coincidence detection scheme to the multibunch hybrid mode of the synchrotron radiation source BESSY II (Helmholtz-Zentrum Berlin). Single-event-based data acquisition and evaluation, combined with the use of relative detection times between the coincident particles, enable the acquisition of proper coincidence signals from a quasi-continuous excitation pattern. The background signal produced by accidental coincidences in the time difference representation is modeled ...
Aufsatz
On the appearance of horseshoe chaos in a nonlinear hysteretic systems with negative stiffness
(2021-09-16)
The problem of inhibition of horseshoe chaos in a nonlinear hysteretic systems using negative stiffness is investigated in this paper. The Bouc–Wen model is used to describe the force produced by both the purely hysteretic and linear elastic springs. The analytical investigation of the Hamiltonian shows that the appearance of separatrix in the system is directly related to the parameters of the hysteretic forces. This means that the transverse intersection between the perturbed and unperturbed separatrix can be ...
Aufsatz
How Do Gaining and Losing Streams React to the Combined Effects of Climate Change and Pumping in the Gharehsoo River Basin, Iran?
(2020-03-18)
Projections of potential impacts of climate change and groundwater abstraction on gaining and losing streams, particularly in ephemeral river basins exhibiting sporadic and intricate flux exchanges, have remained largely unexplored. To fill this gap, we propose a promising modeling scheme based on the new fully integrated hydrological model SWAT‐MODFLOW‐NWT, calibrated and validated for 1978–2012, to quantify the intertwined surface‐groundwater interactions under a conjuncture of three climatic emission scenarios ...
Aufsatz
Self-referencing circular dichroism ion yield measurements for improved statistics using femtosecond laser pulses
(2021-03-10)
The combination of circular dichroism with laser mass spectrometry via the measurement of ion yields is a powerful tool in chiral recognition, but the measured anisotropies are generally weak. The method presented in this contribution reduces the measurement error significantly. A common path optical setup generates a pair of counter-rotating laser foci in the interaction region of a time-of-flight spectrometer. As the space focus condition is fulfilled for both foci individually, this becomes a twin-peak ion source ...