julilili42/papers huggingface dataset:
Topography and climate dictate soil NPK stoichiometry across Africa
2023-02-22

Optimal soil nitrogen-to-phosphorus-to-potassium (NPK) stoichiometry is critical for agricultural production in Africa because it presents the appropriation of input materials to avoid limited or excessive fertilizer applications. Furthermore, an optimum nutrient supply to the plants is crucial to mitigate or eliminating Africa&amp;#8217;s food crisis. However, what drivers influence its levels, distribution and variability across different landscapes and scales? Insights regarding these aspects are necessary for (1) the derivation of robust policies associated with crop production and food security, (2) monitoring of changes associated with hotspot areas between NPK stoichiometry and designated drivers, (3) instigation of suitable and well-targeted efforts to ensure that areas with optimal soil NPK levels are maintained since these eventually affect and influence crop yield output, and (4) identification of areas that are imbalanced in NPK content of the soils and thus may need fertilization. Freely accessible major soil nutrient data [i.e., nitrogen (N), phosphorus (P) and potassium (K)] for Africa were obtained from the iSDAsoil platform, aggregated to 250 m, and used to compute the NPK stoichiometry estimate. In addition, similar NPK stoichiometry estimates were derived for national-scale major food crop exporters, including South Africa, Ethiopia, and Malawi. All these across-scale NPK stoichiometry estimates coupled with different driver estimates (e.g., human activities/agricultural activities/cropping systems, soil texture, soil pH, etc.) provided the data used to assess pairwise mechanistic and explainable model insights using structural equation models [SEM(s)] plus partial dependence plots (PDPs) respectively. Climate-related factors along with topography were the main direct drivers of NPK stoichiometry connected to the topsoil of Africa (i.e., the entire continent including some selected nations). &amp;#160;Human-related activities contributed less to soil NPK stoichiometry. Interestingly, aboveground biomass was discovered to be interdependent with NPK stoichiometry. This cross-scale benchmark alludes to the variations in NPK stoichiometry under both changing climatic conditions and topography in Africa. Keywords: NPK Stoichiometry, Soil Nutrients, Climate Change, Food Security, Structural Equation Modeling, Topographic Effects, Nitrogen, Phosphorus, Potassium, Africa &amp;#160;
Exploring the ‘Individual Treatment Effects’ (ITE) of Vegetation with Causal Inference on Soil Organic Carbon Prediction in Germany
2023-02-22

Carbon is an essential element and contributor to healthy soil conditions as well as ecological soil function and productivity. Additionally, carbon is a component of all plants and animals on the planet and is a necessary component of life. Natural vegetation serves as a significant but highly dynamic carbon sink. When vegetation is removed quicker than it can regenerate, for example by harvesting crops or timber, soil carbon is depleted. Thus, understanding the environmental effects and dynamics of loss of vegetation is a crucial prerequisite to turning our natural resource management from a carbon emitter to a carbon sink to avoid that and achieve sustainability. At the same time, the spatial distribution of soil organic carbon is also highly heterogeneous, with variations in climate, other soil characteristics, and land use/land cover affecting how our ecosystem reacts to the loss of vegetation. Thus, to effectively improve green metrics and contribute to the creation of future policies, it is required to conduct research on the changes in vegetation and their effect on soil organic carbon and provide regionally appropriate management advice. Here, in this research, our goal is to examine the "individual treatment effects" (ITE), which are a personalized or individualized effect estimation of one variable on the output, and utilize causal inference to address them. &amp;#160;Using the LUCAS dataset, we explore the heterogeneous treatment effect of percent tree coverage (PTC), as a parameter of the density of trees on the ground, on the soil organic carbon content in Germany. We do this by leveraging some parameters, such as climate data, land use/land cover information, and other information from the soil. We thus offer a data-driven viewpoint for focusing on sustainable behaviors and effectively increasing soil organic carbon content levels.
Trace element- and Pb isotope fingerprints of natural vs. anthropogenically induced geochemical changes in tropical lake catchments: A case study from lake Naivasha, Kenya
2023-02-22

Continuous lake sediment archives integrate valuable information of geodynamic transformations, climatic fluctuations and anthropogenic environmental forcing through time. In many parts of the world, such as sub-Saharan Africa, lake ecosystems are important pillars of biodiversity and wildlife preservation and evolution, as well as political and economic stability, especially with regard to the rapid population growth and increasing food and water demand.Located in the central part of the rift valley region, lake Naivasha is the second largest freshwater lake in Kenya, covers a catchment area of ca. 3400 km2 and is considered a &amp;#8220;wetland of international importance&amp;#8221; (RAMSAR convention, 2011). Previous studies and real-time observations documented a rapid intensification of agricultural activities ranging from subsidy economy (upper catchment) to industrial-sized horticulture practices (lower catchment) from the second half of the 20th century towards the present. These were suggested to have significantly influenced the drainage systems of the catchment and hydrochemistry of the lake, with potentially negative effects on the entire ecosystem. In addition, potential anthropogenic metal influx from other modern, diffuse sources (such as fossil fuel combustion) due to the increasing anthropogenic density and activities in the immediate vicinity of the lake remain poorly constrained.We analysed major- and trace elements and Pb isotope compositions of lake sediments covering the past ca. 150 years, as well as the surrounding lithologies in order to reconstruct the pathway(s) and source(s) of elemental influx and accumulation into the lake. The characterization of the geological background in this tectonically and volcanologically active region was primarily set on the northern part of the catchment where, the two main lake-feeding rivers Malewa and Gilgil discharge into the lake. Element correlation indices point to i) a strong influence of the local geological background and, ii) a relatively stable catchment for this time-period as seen from sub-parallel REE+Y patterns along the monolith. Lead isotope compositions, on the other hand, show more radiogenic values in the sediment deposited before the 1900&amp;#8217;s (206Pb/204Pb: 19.502 &amp;#8211; 19.546) and a significant shift towards less radiogenic isotopic ratios from the second half of the 20th century (206Pb/204Pb: 19.228 &amp;#8211; 19.304), which persists towards the top of the core. We combine our extended geochemical data with geospatial projections of the land use to build a time-integrated cause-and-effect assessment of metals into lake Naivasha and disentangle the cause for the change in the Pb isotope composition.
A model-based exploration of mid-Holocene anti-phase climate variations in the Central Andes
2023-02-22

The Andes&amp;#8217; elevation of ~4 km and great meridional extent of ~50&amp;#176;S to 10&amp;#176;N greatly influences the spatial climate patterns across the South American continent. Apart from latitude and altitude, quasi-stable pressure systems modify the climate of the region. The Bolivian high, an upper-level anticyclonic circulation over the central part of the continent, is one such feature and has a strong impact on atmospheric moisture transport and the regional hydroclimate of the Central Andes. Orbitally forced shifts in the Bolivian High have been hypothesised to be responsible for anti-phase palaeoclimate changes in Peru in the mid-Holocene, such as the increase in humidity in the Palpa region and synchronous extreme drought near Lake Titicaca [e.g., M&amp;#228;chtle et al. 2013]. However, this hypothesis has not been tested, and it has not been determined how much of the mid-Holocene hydroclimate change in the Central Andes can be explained by changes in regional pressure systems. Here, we test the hypothesis that mid-Holocene orbital variations and palaeogeographical changes modified pressure fields and regional moisture transport, and lead to anti-phase changes in regional hydroclimate. We test this hypothesis using the physics-based, isotope-tracking climate model ECHAM5-wiso. More specifically, we analyse pre-industrial and mid-Holocene paleoclimate simulations [Mutz et al. 2018]&amp;#160; to track changes in pressure fields and moisture transport. We then assess their impacts on regional hydroclimate in the Central Andes. Results indicate that: (a) the climate models reproduce the observed synchronous anti-phase (wetter and drier) climate changes documented in different parts of Peru, and (b) these can be explained by changes in the regional pressure and wind fields. Taken together, previous proxy-based observations and model results present here indicate that orbital variations drive changes in the regional pressure systems and lead to spatially heterogenous variations in hydroclimate across the Central Andes.
Disruption of a high-pressure unit during exhumation: petrology and geochronology of garnets within the Cycladic Blueschist Unit (Thera, Ios and Naxos islands, Greece)
2023-02-22

Understanding the disruption of a tectonic nappe that experiences a subduction-related pressure temperature (P-T) loop is challenging. Thrust imbrications may disrupt single nappes during its subduction and/or exhumation which can be revealed by detailed petrological and geochronological work. Garnet commonly forms during subduction. It most likely hosts early prograde, peak high-pressure (HP) and subsequent metamorphic mineral inclusions making such assemblages a useful tool for detailed petrological and geochronological investigations. Multiple approaches were used to determine the detailed P-T loop of the Cycladic Blueschist Unit passive margin sequence (Greece) such as Zr-in-rutile thermometry coupled with quartz-in-garnet elastic barometry, average P-T and phase equilibrium thermodynamic modeling. U-Pb garnet and zircon geochronology age data were in addition determined to complement already existing age data.The results of this approach reveal that the passive margin sequence in Thera (Santorini), Ios and Naxos was subducted as a coherent continental fragment at a subduction rate of ~2.1 km/My and a heating rate of ~12 &amp;#176;C/My. Prograde and peak HP metamorphism occurs at c. 50 and c. 40 Ma respectively.&amp;#160; Along Thera, Ios and Naxos, prograde and peak P-T condition increase from sub-blueschist to upper blueschist facies metamorphism. Subsequently, the sequence was disrupted by one or several thrust faults during its exhumation. The passive margin sequence of Naxos was thrust onto the Ios sequence during the Oligocene at c. 30 Ma. This imbrication is revealed by different exhumation rates of ~6 km/My for the passive margin sequence of Naxos and of ~3 km/My for the one of Ios. The passive margin sequence of Thera, Ios and the upper part of Naxos was exhumed to upper crustal levels, whereas the lower part of the Naxos passive margin sequence was exhumed to the lower crust leading to thermal relaxation of 9&amp;#8211;96&amp;#176;C following tectonic accretion. This indicates that thermal relaxation following tectonic accretion in the Cyclades controlled the thermal evolution of the evolving Cycladic orogen during a tectonically quiet period before lithospheric extension.
Atmosphere-mediated response of the Southern Hemisphere hydroclimate in simulations of spontaneous Dansgaard-Oeschger-like oscillations
2023-02-22

Dansgaard-Oeschger (DO) events are the most iconic mode of millennial-scale variability during the last glacial period. The manifestation of DO events outside the North Atlantic region and mechanisms responsible for the propagation of the North Atlantic signal across the globe are still little understood. Propagation of DO events to the Southern Hemisphere (SH) has first been explained by oceanic processes, that result in a muted and delayed signal in the Antarctic ice core record, known as Antarctic Isotope Maxima (AIM). Recent ice core-based reconstructions found an additional short-timescale response (years-to-decades, compared to centuries for the oceanic processes) in phase with the climate changes in Greenland. This fast response has been interpreted as the result of atmospheric transport processes. Shifts in the intertropical convergence zone and SH mid-latitude westerlies are seen as mediators of this response.Here, we investigate the propagation of abrupt climate changes in the North Atlantic region to the SH in general circulation model simulations with spontaneous DO-like oscillations under glacial conditions. We study the relative timing of changes in temperature, hydroclimate, and atmospheric circulation and compare our results with ice core and speleothem based reconstructions. In the simulations, the timing of changes in different elements of the climate system varies on a continuum of timescales from months to centuries. This indicates the existence of more complex propagation mechanisms than the simple separation into an atmospheric and an oceanic mode. Our work emphasizes that future analysis of simulations of DO-like events should focus not just on the mechanisms responsible for the spontaneous oscillations but also on the spatio-temporal fingerprint of the oscillations across the globe.
The Effect of Laser-induced Heating on Moganite, Silanole and Quartz during Raman Spectroscopy
2023-02-22

Moganite is a silica polymorph found intergrown with microcrystalline quartz. Raman spectroscopy is used to detect moganite using a band at 501 cm-1, generated by the vibration of a four-membered tetrahedral SiO2. This band is numerically distinct from the most intense band used to identify quartz at 465cm-1, and thus Raman spectroscopy might be considered a reliable methodology to detect moganite. However, the moganite detection using Raman spectra must be done with caution since a band at 503 cm-1 can be caused by a Si-O vibration of silanole (SiOH), and thus the two bands interfere and may mingle. Such interference might be mitigated or increased by sample preparation, but it has not previously been shown with certainty whether powdered or intact rock surfaces, would exhibit the greatest interference. Here, we present a Raman spectroscopic study of different particle sizes on moganite and flint to investigate how it affects moganite detection. We found a Raman band in pristine flint with a similar peak position to moganite, but subsequent to heat treatment at 700 &amp;#730;C for 6 hours, the band disappeared indicating the presence of silanole rather than moganite. Powdering the sample in combination with the use of higher laser powers increased this effect and the relative intensity of the silanole band. Overall, the Raman spectrum of flint was found to be more sensitive to laser-power-induced artifacts than moganite. Aggregated quartz powder is known to be affected by laser-induced heating during Raman spectroscopy. However, the effect of the heating on silanole and moganite bands is not as well documented. The peak shift of moganite has a similar trend to the phase transition detected by Raman Spectroscopy and XRD with heat thus the two approaches are consistent. Furthermore, the silanole band is known to change its position by 6 cm-1 at heating from room temperature to 600 &amp;#730;C. Based on the results from other research, the peak shift and broadening in the present study can be interpreted as an effect of laser-induced heating. To date, for mineral analyses, the number of studies reporting the effects of laser-induced heating on minerals is limited, which contrasts strongly with Raman spectroscopy of organic materials. The result in the present study suggests that the band shift of silanole and the transition of &amp;#945;-&amp;#946; moganite can be caused by the heat of the laser should be taken into consideration especially when small particle size moganite is being identified by Raman Spectrum. However, this same sensitivity to temperature may indicate potential as a measure of paleotemperature.
Anthropogenic activities significantly increase annual greenhouse gas (GHG) fluxes from temperate streams, rivers, and drainage ditches in Germany
2023-02-22

Anthropogenic activities increase the contributions of inland waters to global greenhouse gas (GHG; CO2, CH4, and N2O) budgets, yet the mechanisms driving these increases are still not well constrained. In this study, we quantified year-long GHG concentrations and fluxes, as well as water physico-chemical variables from 23 streams, three ditches, and two wastewater inflow sites across five catchments in Germany contrasted by land use. Using mixed-effects models, we determined the overall impact of land use and seasonality on the intra-annual variabilities of these parameters. We found that land use was more significant than seasonality in controlling the intra-annual variability of GHG concentrations and fluxes. Agricultural land use and wastewater inflows in settlement areas resulted in elevated riverine CO2, CH4, and N2O emissions, as substrate inputs by these sources appeared to favor in situ GHG production processes. Dissolved GHG inputs directly from agricultural runoff and waste-water inputs also contributed substantially to the annual emissions from these sites. Drainage ditches were hotspots for CO2 and CH4 fluxes due to high dissolved organic matter concentrations, which appeared to favor in situ production via respiration and methanogensis. Overall, the annual emission from anthropogenic-influenced streams and rivers in CO2-equivalents was up to 20 times higher (~71 kg CO2 m-2 yr-1) than from natural streams (~3 kg CO2 m-2 yr-1). Future studies aiming to estimate the contribution of riverine systems to GHG emissions should therefore focus on anthropogenically perturbed streams, as their GHG emission are much more variable in space and time.
Temporal activity of subglacial channels around the grounding line of Roi Baudouin Ice Shelf, from ice-penetrating radar
2023-02-22

The existence of ice-shelf basal channels has a significant impact on both buttressing ability and basal melting of ice shelves in Antarctica. Although they can provide a unique perspective of processes for the mass transfer from grounded ice sheet to floating ice shelf, their origination and evolution are still not fully understood.Here we used airborne and ground-based radar to investigate the subglacial channel features at the grounding line (GL). We determined the geometry of five channels (two of which are characterized for the first time) in a set of flow-perpendicular radar profiles, also perpendicular to the channels. We found that the evolution from grounded subglacial channels to the ice-shelf basal channels mainly goes through three stages: (1) The grounded subglacial channels appear 4 to 5 km upstream of the GL and their incision into the ice sheet increases while approaching the GL; (2) as the subglacial channels extend into the grounding zone (1 to 2 km downstream of GL), their inner walls started melting, also they keep their roof-top features; (3) on the shelf interaction with the ocean, surface accumulation and ice dynamics further lead to flattening and widening, progressively turning them into generally known ice-shelf basal channels.Additionally to radar observations, we investigated the role of subglacial hydrology with two modelling approach (subglacial water flux with CUAS-MPI and water routing with CiDRE). A comparison shows that most channel locations in the radar profiles match with areas of higher subglacial water presence, consequently implying that subglacial water flux could mainly be responsible for maintaining the presence of subglacial channels.Based on the already earlier proposed relation that the presence of a sub-ice shelf basal channel is linked to a corresponding channel at the GL, we identify one now active channel at the GL to be related to one which was earlier until 59 years ago. This indicates that basal channels and consequently basal water flux across the GL can change at least on the scale of centuries. Our observed reactivation of a subglacial channel confirms the suitability of basal channels in ice shelves to be used as proxies of past subglacial hydrological activities and other potentially larger events.
Paediatric User Guide (Data Standards User Guide for Paediatrics)
2023-02-22

&lt;p&gt;Clinical Data Interchange Standards Consortium (CDISC) and conect4children (c4c) have announced the release of a Paediatrics User Guide, freely available on the CDISC website (free CDISC registration required), to facilitate the development of medicines for children. The User Guide focuses on cross-cutting clinical concepts related to paediatric research and describes how to use CDISC standards to collect and structure data used in clinical trials to facilitate the aggregation of information, take advantage of big data and support data sharing.&nbsp; Adopting CDISC standards is an invaluable investment that leads to more meaningful, more efficient research by streamlining the flow of data throughout the research process.&lt;/p&gt; &lt;p&gt;&nbsp;&lt;/p&gt;
Comparative analysis of EpCAM high-expressing and low-expressing circulating tumour cells with regard to their clonal relationship and clinical value
2023-02-23

Abstract Background Circulating tumour cells (CTCs) are mainly enriched based on the epithelial cell adhesion molecule (EpCAM). Although it was shown that an EpCAM low-expressing CTC fraction is not captured by such approaches, knowledge about its prognostic and predictive relevance and its relation to EpCAM-positive CTCs is lacking. Methods We developed an immunomagnetic assay to enrich CTCs from metastatic breast cancer patients EpCAM independently using antibodies against Trop-2 and CD-49f and characterised their EpCAM expression. DNA of single EpCAM high expressing and low expressing CTCs was analyzed regarding chromosomal aberrations and predictive mutations. Additionally, we compared CTC-enrichment on the CellSearch system using this antibody mix and the EpCAM based enrichment. Results Both antibodies acted synergistically in capturing CTCs. Patients with EpCAM high-expressing CTCs had a worse overall and progression-free survival. EpCAM high- and low-expressing CTCs presented similar chromosomal aberrations and mutations indicating a close evolutionary relationship. A sequential enrichment of CTCs from the EpCAM-depleted fraction yielded a population of CTCs not captured EpCAM dependently but harbouring predictive information. Conclusions Our data indicate that EpCAM low-expressing CTCs could be used as a valuable tumour surrogate material—although they may be prognostically less relevant than EpCAM high-expressing CTCs—and have particular benefit if no CTCs are detected using EpCAM-dependent technologies.
Mitophagy in ototoxicity
2023-02-23

Mitochondrial dysfunction is associated with ototoxicity, which is caused by external factors. Mitophagy plays a key role in maintaining mitochondrial homeostasis and function and is regulated by a series of key mitophagy regulatory proteins and signaling pathways. The results of ototoxicity models indicate the importance of this process in the etiology of ototoxicity. A number of recent investigations of the control of cell fate by mitophagy have enhanced our understanding of the mechanisms by which mitophagy regulates ototoxicity and other hearing-related diseases, providing opportunities for targeting mitochondria to treat ototoxicity.