julilili42/papers huggingface dataset:
The role of maize root exudates to availability of N source in different forms in top- and subsoils
2022-03-27

&amp;lt;p&amp;gt;Nitrogen (N) availability is a main constraint to plant productivity, especially when vegetation relies largely on subsoils, which contain considerable N resources but in low availability. Rhizodeposition can promote N cycling by stimulating microbial growth and activity and thus induces the release of mineral-bound nutrients and accelerates decomposition of soil organic matter (SOM). However, many specific processes how root exudates interact with distinct N forms altering their subsoil mobilization still remain unclear. We hypothesize that the lower microbial activity but higher sorption capacity of subsoils induces subsoil-specific N dynamics. To disentangle this, we added four N sources (free NH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;+&amp;lt;/sup&amp;gt;, sorbed NH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;+&amp;lt;/sup&amp;gt;, urea and plant residues with identical total N content) into top-and subsoils. We quantified microbial processes regulating mineral and organic N availability in top-and subsoils by simulating rhizosphere condition via application of collected root exudates in a well-controlled microcosm experiment. Our results showed that neither growth of the total microbial community, nor shift in the community composition occurs based on maize root exudate amendment resembling a daily exudation amount. However, we observed a clear increase in microbial activity and activation of organic nutrient mobilizing mechanisms (e.g. enzyme activation), which was in most cases higher in sub- than in topsoils. This suggests that root exudates may not be of highest relevance for topsoil nutrient mobilization. In contrast, high root exudation is of much higher relevance for crops, which aim to mobilize a significant proportion of their nutrients from subsoils. We could demonstrate that subsoil communities were well capable of using litter-derived N, especially if root exudates accelerate overall activity and N cycling in subsoils. N incorporated from plant litter is successively recycled in microbial bio-and necromass following the initial degradation. Consequently, if breeding for deep-rooting crops with nutrient uptake from subsoils shall be promoted in the future, it is essential to ensure that these crops deep roots have a high root exudation to activate the highly C limited microbial communities of the subsoil.&amp;lt;/p&amp;gt;
Andean geodynamics and the evolution of the Amazonian ecosystem
2022-03-27

&amp;lt;p&amp;gt;The evolution of the Amazonian landscape is directly related to the development of the Andean Cordillera and its interaction with climate and other geodynamic processes. The Andean orogeny shaped the climate in South America and changed the precipitation rates across the continent. The continuous increase in erosion rates mainly along the eastern flank of the cordillera amplified the influx of sediments in Amazonia, culminating in the formation of the transcontinental Amazon Drainage Basin nearly 10 million years ago (Ma), connecting the Andean Cordillera and the Equatorial Atlantic Margin. Concomitantly, flexure of the lithosphere due to the load of the Andes and dynamic topography induced by the subduction of the Nazca plate under the western margin of South America modified the landscape in Amazonia.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Due to the complexity of the different processes associated with the geodynamic evolution of northern South America during the last 40 Ma, a natural approach to this study is the use of numerical models that take the interaction of the different geodynamic processes into account. Based on numerical models that combine orogeny, surface processes, flexure of the lithosphere, mantle dynamics, and paleoclimate scenarios, we show how the different habitats in Amazonia probably evolved during the formation of the Andean Cordillera. We observed that the continuous uplift of the Andes created an asymmetric influx of sediments and nutrients in Western Amazonia, inducing the eastward expansion of v&amp;amp;#225;rzea and terra firme forests during the Miocene. Consequently, the igap&amp;amp;#243; forests retracted and were preserved mainly adjacent to the Guiana and Brazilian shields. Additionally, before the formation of the transcontinental river, large aquatic environments were formed in Western and Central Amazonia, with spatial and temporal extent modulated by climate, sea-level fluctuations, and amplitude of dynamic topography, controlling the transition from the intermittent marine environment to lacustrine conditions, similar to the long-lived lakes of the Pebas System during the Late Miocene. We propose that these landscape evolution scenarios are compatible with the flourishing and extinction of endemic species during the Late Miocene and can explain part of the present pattern of biodiversity observed in the largest rainforest on Earth.&amp;lt;/p&amp;gt;
Assessing the geometry of the Main Himalayan thrust in central Nepal: Insights from thermokinematic modelling
2022-03-27

&amp;lt;p&amp;gt;The 2015 Gorkha earthquake reignited an existing debate about whether geometric barriers on faults play a role in containing the propagation of ruptures. Models suggest that the extent of the Gorkha earthquake rupture, and of other historical earthquakes were controlled by the locations of ramps in the Main Himalayan thrust (MHT), notably on the western edge of the rupture. The existence of such a pronounced lateral boundary to the west of the Gorkha epicenter is supported by an offset in the surface trace of the Main Central thrust (MCT), closely followed by an offset in the distribution of young (&amp;lt;5 Ma) muscovite &amp;lt;sup&amp;gt;40&amp;lt;/sup&amp;gt;Ar/&amp;lt;sup&amp;gt;39&amp;lt;/sup&amp;gt;Ar (MAr) ages. However, the zircon (U-Th)/He (ZHe) and apatite fission track ages show more linear east-west distributions over the same region, as does Physiographic Transition 2 (PT2). We explore the formation of these relationships by combining forward-modeled balanced cross-sections through the Marsyangdi, Daraundi, and Budhi Gandaki valleys in central Nepal, and investigate the continuity of active structures across the western portion of the Gorkha rupture. The sequential kinematics of each of these sections are combined with a thermokinematic model (PECUBE) to evaluate the exhumation and cooling histories of the rocks exposed at the surface. We gauge the validity of these models by comparing their predicted cooling ages to measured ages, discarding those that do not match the measured distribution of cooling ages.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Our 3D models show that the offset in the surface geology along the Daraundi is due to a shorter (by 1/3) Trishuli thrust sheet, that has been completely translated to the south of the modern ramp and folded by the Lesser Himalayan duplex. Similarly, the southern extent of the reset MAr ages is also controlled by these relationships requiring observed surface offsets to be the result of changes in the hanging wall rocks translated over the ramp, rather than changes in the geometry of the modern ramp. Notably, the continuity and location of the modern MHT ramp is evidenced by the linear distribution of the youngest ZHe and AFT ages, which are most sensitive to the location of the active ramp. Additionally, the out-of-sequence thrust responsible for PT2 soles directly into the modern ramp during its proposed period of activity at ~1.2 Ma, resulting in the highly linear trace of PT2, running parallel to the location of the ramp. These linear relationships and their reproducibility in thermo-kinematic models argue strongly against any geometric offsets in the modern MHT ramp that have been proposed to limit rupture propagation in central Nepal.&amp;lt;/p&amp;gt;
Towards interpretation of the radio-stratigraphy of Antarctic ice shelves from modeling and observations: A case study for the Roi Baudouin Ice Shelf, East Antarctica &#160;
2022-03-27

&amp;lt;p&amp;gt;Ice shelves surrounding the Antarctic perimeter buttress ice flow from the continent towards the ocean, and their disintegration leads to an increase in ice discharge and sea level rise. The evolution and integrity of ice shelves is governed by surface accumulation, basal melting, and ice dynamics. We find history of these processes imprinted in the ice-shelf stratigraphy, which is mapped using isochrones imaged with radar. As an observational archive, the radar obtained stratigraphy combined with ice flow modeling has high potential to assist model calibration and reduce uncertainties in projections for the ice-sheet evolution. In this study we use a simplistic and observationally driven ice-dynamic forward model to predict the ice-shelf stratigraphy. We validate this approach with the full Stokes ice-flow model Elmer/Ice, and present a test-case for the Roi Baudouin Ice Shelf (East Antarctica) - where our model predictions agree well with radar obtained observations. The presented method enables us to investigate whether ice shelves are in steady-state, as well as to map spatial variations of how much of the ice-shelf volume is determined by its local surface mass balance. In the case of Roi Baudouin, we find the ice-shelf volume in the western part to be dominated by ice inflowing from the ice sheet, while the eastern part of the ice shelf is dominated by ice locally accumulated on the shelf. Such analysis serves as a metric for the susceptibility of ice shelves to climate change. We further apply our approach to other ice shelves in Antarctica.&amp;lt;/p&amp;gt;
Influence of offshore wind farms on the latent heat flux in the marine boundary layer
2022-03-27

&amp;lt;p&amp;gt;Unique airborne in-situ measurements were evaluated to investigate the influence of offshore wind farms on the latent heat flux in the marine boundary layer. 21 of the total 42 measurement flights carried out in the frame work of the WIPAFF project over the German Bight in the years 2016 and 2017 &amp;amp;#160;enabled such an evaluation under different atmospheric conditions. The measurements of 15 flights showed a significant increase of the vertical upward latent heat flux over the offshore wind farm clusters Amrumbank West, Nordsee Ost, Meerwind S&amp;amp;#252;d/Ost or the wind farm Godewind. Under thermally stable conditions, all except one of the measurement flights showed an increase of latent heat flux over or in the wake of the wind farms, with an heat flux up to 17 times higher compared to the undisturbed flow. During flights under unstable thermal stratification, the phenomenon was observed in 8 out of 13 cases. The results also suggest that not only thermal stratification but also moisture stratification plays a decisive role in whether the influence of the wind farm becomes noticeable in the latent heat flux. &amp;amp;#160;Considering the absolute amount of the increase of the upward latent heat flux, a maximum increase of +400 W/m&amp;amp;#178; was measured in unstable conditions.&amp;amp;#160;&amp;lt;/p&amp;gt;
Best practices for collecting polarimetric data with ApRES for constraining ice-fabric orientation and its spatial variability
2022-03-27

&amp;lt;p&amp;gt;In recent years radar polarimetry has re-surfaced as an ideal tool to determine ice-fabric patterns and linked mechanical ice anisotropy. The leap forward was facilitated by coherent data processing often collected by phase-sensitive Radio-Echo-Sounding (pRES) systems at fixed locations. The polarimetric response can either be synthesized from a set of quad-polarimetric measurements or obtained by manually rotating the antennas. Specifics of the data collection in the field varied between the different surveys, and no set of best practices has yet emerged. &amp;amp;#160;Here we present a systematic study that includes more than fifty different combinations of how polarimetric data can be acquired, including:&amp;lt;/p&amp;gt;&amp;lt;ul&amp;gt;&amp;lt;li&amp;gt;different distances between the transmitter and receiver (2, 4 and 8 m)&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;different combinations in polarization orientation (22.5 deg)&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;a comparison between discrete full azimuthal data collected every 22.5 degrees and synthesized data collected in a quad-pole setup&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;the effect of 180-degree polarization orientation on repeat measurements, e.g., basal melt rate and polarimetric analysis, e.g., coherence phase&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;definition of Horizontal (H) and Vertical (V) orientation is pRES antenna setup and its impact on synthesizing and analyzing data&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;90-degree fabric orientation ambiguity in polarimetric data&amp;lt;/li&amp;gt; &amp;lt;/ul&amp;gt;&amp;lt;p&amp;gt;This study aims to provide best practices, considering that observation time in the field is limited. Ideally, this will lead to a unified setup and nomenclature, facilitating better compatibility from data collected by different groups on ice sheets, shelves, and glaciers.&amp;lt;/p&amp;gt;
Role of iron-carbon interactions in the release of greenhosue gases from permafrost systems
2022-03-27

&amp;lt;p&amp;gt;As permafrost thaws, vast stocks of organic carbon previously accumulated within these systems are vulnerable to microbial decomposition and may be released as the greenhouse gases CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;. The release of carbon from permafrost systems is expected to lead to runaway positive feedbacks. The timescale and magnitude of the permafrost-climate feedback is highly uncertain as knowledge gaps remain regarding the rate of decomposition of permafrost organic carbon. These knowledge gaps stem, in part, from poor understanding of the association between organic carbon (in the form of organic matter) and minerals, especially high surface area iron minerals. In this work, we investigated the coupling of iron and carbon cycles in permafrost peatlands and its effect on greenhouse gas release. We first showed that up to 20% of the organic carbon in intact permafrost sites may be associated with iron(III) (oxyhydr)oxides and thereby protected from microbial decomposition. At the onset of thaw, this association is broken down, likely due to the microbial reduction of iron(III), and previously protected carbon is thus released. Using microbiological and molecular biological tools, we linked this breakdown to an increase in the abundance of methanogenic microorganisms and concentrations of methane. Preliminary work also suggests that part of the released organic carbon may re-associate with dissolved iron in thaw ponds to form flocs. Currently, we are investigating the molecular composition of organic matter as it undergoes these redox processes with the goal of linking bioavailability to composition. We complement this work with enrichment experiments and microbial community analyses to determine the microbial key players controlling iron(III) reduction and the potential for subsequent microbial Fe(II) oxidation. Collectively, the results of this project suggest that upon thawing, organic matter previously associated with minerals is mobilized and is likely susceptible to microbially-mediated release as CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;.&amp;lt;/p&amp;gt;
Development of micro-zymography: microscopic visualization of enzymatic activity in soil aggregates and Zea mays L. root
2022-03-27

&amp;lt;p&amp;gt;Enzymes are secreted by microbial cells into the soil to catalyze the acquisition of carbon or nutrients like nitrogen and phosphorus from soil organic matter. Apart from microorganisms and soil fauna, roots also secrete enzymes to mobilize nutrients from the soil nutrient pool. Thus, living plants and microorganisms are considered the main sources of soil enzymes in agroecosystems. To understand how exo-enzymes are distributed in soil microhabitats, and whether enzymatic activity is higher in soil solution or on particle surfaces, we visualized enzymatic activity at the corresponding scale. Visualization of enzymatic activity links microbial functioning to localization in heterogeneous soil habitats. To assess enzymatic reactions in soil at the microscopic level, we developed a micro-zymography approach based on fluorogenically-labeled substrate (phosphomonoesterase) in the rhizosphere soil of &amp;lt;em&amp;gt;Zea mays&amp;lt;/em&amp;gt; L. For this, first we compared different fixatives required to prevent sample drying and found super transparent silicon as the most appropriate one. Then we evaluated micro-zymography i) on individual soil aggregates, ii) on thin layers of aggregates (&amp;amp;#8776; 500 &amp;amp;#181;m) to assess the dynamics of phosphomonoesterase activity, and iii) on maize roots under laser scanning microscope. The results demonstrated that the main fluorescence signal shifted from the soil solution to the interface between the soil solution and aggregates within 30 min after substrate addition and was finally only detectable on the surface of a few aggregates. This was probably due to higher microbial abundance and enzymatic activity on the soil aggregates compared to the soil solution. The enzymatic activity appeared patchy on the aggregate surfaces indicating heterogeneous distribution of microorganisms. Similarly, a patchy distribution of enzymatic activity was detected on maize root surfaces. This work was conducted within the framework of the priority program 2089 &amp;amp;#8220;Rhizosphere spatiotemporal organization &amp;amp;#8211; a key to rhizosphere functions&amp;amp;#8221;, funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) &amp;amp;#8211; Project number: 403664478. Seeds of the maize were provided by Caroline Marcon and Frank Hochholdinger (University of Bonn).&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;Keywords:&amp;lt;/strong&amp;gt; exo-enzyme, micro-zymography, fixative&amp;lt;/p&amp;gt;
Efficacy of Tricaine (MS-222) and Hypothermia as Anesthetic Agents for Blocking Sensorimotor Responses in Larval Zebrafish
2022-03-28

Tricaine, or MS-222, is the most commonly used chemical anesthetic in zebrafish research. It is thought to act via blocking voltage-gated sodium channels, though its mechanism of action, particularly at the neuronal level, is not yet fully understood. Here, we first characterized the effects of tricaine on both body balance and touch responses in freely swimming animals, before determining its effect on the neural activity underlying the optokinetic response at the level of motion perception, sensorimotor signaling and the generation of behavior in immobilized animals. We found that the standard dose for larvae (168 mg/L) induced loss of righting reflex within 30 seconds, which then recovered within 3 minutes. Optokinetic behavior recovered within 15 minutes. Calcium imaging showed that tricaine interferes with optokinetic behavior by interruption of the signals between the pretectum and hindbrain. The motion sensitivity indices of identified sensory neurons were unchanged in larvae exposed to tricaine, though fewer such neurons were detected, leaving a small population of active sensory neurons. We then compared tricaine with gradual cooling, a potential non-chemical alternative method of anesthesia. While neuronal tuning appeared to be affected in a similar manner during gradual cooling, gradual cooling induced a surge in calcium levels in both the pretectum and hindbrain. This calcium surge, alongside a drop in heartrate, is potentially associated with harmful changes in physiology and suggests that tricaine is a better anesthetic agent than gradual cooling for zebrafish laboratory research.
Platelet P2Y12 inhibiting therapy in adjunct to vascular dose of rivaroxaban or aspirin: a pharmacodynamic study of dual pathway inhibition vs. dual antiplatelet therapy
2022-03-28

Abstract Aims Dual pathway inhibition (DPI) by adding a vascular dose of rivaroxaban to a single antiplatelet agent has emerged as a promising antithrombotic strategy. However, in most studies the antiplatelet agent of choice used in adjunct to a vascular dose of rivaroxaban was aspirin, and data on a P2Y12 inhibitor and how this DPI regimen compares with standard dual antiplatelet therapy (DAPT) are limited. Methods and results This investigation was a substudy analysis conducted in selected cohorts of patients with stable atherosclerotic disease enrolled from a larger prospective, open-label, parallel-group pharmacodynamic (PD) study. We analysed data from 40 patients treated with either clopidogrel- or ticagrelor-based DAPT first, and clopidogrel- or ticagrelor-based DPI thereafter. PD measures explored key pathways involved in thrombus formation and included markers of (1) P2Y12 reactivity, (2) platelet-mediated global thrombogenicity, (3) cyclooxygenase-1 activity, (4) thrombin receptor-activating peptide (TRAP)-induced platelet aggregation, (5) tissue factor (TF)-induced platelet aggregation, and (6) thrombin generation. Compared with DAPT, on a background of the same P2Y12 inhibitor (clopidogrel or ticagrelor), DPI was associated with reduced thrombin generation, increased markers of cyclooxygenase-1 activity and TRAP-induced platelet aggregation, and no differences in markers of P2Y12 signalling, platelet-mediated global thrombogenicity, and TF-induced platelet aggregation. In an analysis according to P2Y12 inhibitor type, ticagrelor reduced markers of platelet-mediated global thrombogenicity, P2Y12 signalling, and rates of high platelet reactivity compared with clopidogrel. Conclusion Compared with DAPT with aspirin and a P2Y12 inhibitor, the use of a P2Y12 inhibitor in adjunct to a vascular dose of rivaroxaban as part of a DPI strategy is associated with similar effects on platelet-mediated global thrombogenicity but reduced thrombin generation. A DPI strategy with ticagrelor is associated with enhanced antithrombotic efficacy, the clinical implications of which warrant larger scale investigations. Clinical trial registration ClinicalTrials.gov identifier: NCT03718429.
Water Isotopic Signature of Surface Snow Metamorphism in Antarctica
2022-03-28

&amp;lt;p&amp;gt;Water isotope ratios of ice cores are a key source of information on past temperatures. Through fractionation within the hydrological cycle, temperature is imprinted in the water isotopic composition of snowfalls. However, this signal of climatic interest is modified after deposition when snow remains at the surface exposed to the atmosphere. Comparing time series of surface snow isotopic composition at Dome C with satellite observations of surface snow metamorphism, we found that long summer periods without precipitation favor surface snow metamorphism altering the surface snow isotopic&amp;amp;#160; composition. Using excess parameters (combining dD, d&amp;lt;sup&amp;gt;17&amp;lt;/sup&amp;gt;O, and d&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O fractions) allow the identification of this alteration caused by sublimation and condensation of surface hoar. The combined measurement of all three isotopic compositions could help identifying ice core sections influenced by snow metamorphism in sites with very low snow accumulation.&amp;lt;/p&amp;gt;
Anodal stimulation of inhibitory control and craving in satiated restrained eaters
2022-03-28

Results replicated an inhibitory control deficit in RE with longer SSRTs compared to URE without stimulation. During anodal tDCS to the rIFG, reduced SSRTs in RE indicated an improvement in inhibitory control. The findings suggest a specificity of rIFG stimulation in at-risk groups with regards to inhibitory control irrespective of craving.