julilili42/papers huggingface dataset:
Glyphosate contamination in European rivers not from herbicide application?
2024-03-11

<title>Abstract</title> The most widely used herbicide glyphosate contaminates surface waters around the globe. Being toxic to aquatic organisms and a possible carcinogenic, mitigation strategies attempt to reduce river contamination, but their impact is not evaluated. Investigating long-term time series, we discovered that – in contrast to the USA – glyphosate river water concentration patterns in Europe contradict a dominant input from herbicide application. Our large meta-analysis clearly shows that for decades, the main source of glyphosate has been municipal wastewater, visible in the close correlation to concentration patterns of, <italic>e.g.</italic>, pharmaceuticals, rather high and constant loads all over the year and failure of mitigation strategies. We suspect that glyphosate enters European rivers as a transformation product of aminopolyphosphonates, which are used in European but not U.S. detergents.
Pre-trained molecular representations enable antimicrobial discovery
2024-03-11

Abstract The rise in antimicrobial resistance poses a worldwide threat, reducing the efficacy of common antibiotics. Determining the antimicrobial activity of new chemical compounds through experimental methods is still a time-consuming and costly endeavor. Compound-centric deep learning models hold the promise to speed up this search and prioritization process. Here, we introduce a lightweight computational strategy for antimicrobial discovery that builds on MolE ( Mol ecular representation through redundancy reduced E mbedding), a deep learning framework that leverages unlabeled chemical structures to learn task-independent molecular representations. By combining MolE representation learning with experimentally validated compound-bacteria activity data, we design a general predictive model that enables assessing compounds with respect to their antimicrobial potential. The model correctly identified recent growth-inhibitory compounds that are structurally distinct from current antibiotics and discovered de novo three human-targeted drugs as Staphylococcus aureus growth inhibitors which we experimentally confirmed. Our framework offers a viable cost-effective strategy to accelerate antibiotics discovery.
Preparatory experiments to investigate the vesicle formation of hydrous lower Laacher See phonolite at near liquidus conditions
2024-03-11

The Laacher See volcano in the Eifel region of western Germany caused one of the largest eruptions in Central Europe within the last 100,000 years. The Plinian eruptions lasted days to weeks and ejected about 6.3 km&amp;#179; phonolitic magma. The ascent and subsequent discharge of magma is greatly influenced by the amount of dissolved H2O. During the magma ascent the solubility of H2O in the melt decreases while simultaneously the supersaturation of the melt increases. This is the prerequisite for phase separation, which leads to the formation of volatile bubbles.A set of high temperature decompression experiments with hydrous lower Laacher See phonolite (LLST) has recently been conducted at high temperature superliquidus conditions of 1323 K and starting pressure of 200 MPa showing spontaneous phase separation (Marks and Nowak 2024) at a final pressure of 80 MPa. In order to investigate the temperature dependence of vesicle formation, preparatory phase relation experiments were conducted in the cold seal pressure vessel at low temperature near liquidus conditions. Synthetic glass cylinders of the LLST composition were hydrated for 11 days with excess H2O at 1123 K and 200, 90, and 70 MPa to obtain H2O solubility data and pressure dependent liquidus conditions.The hydrated and quenched sample at 200 MPa is a crystal-free homogeneous glass with residual H2O fluid. The H2O content of the glass was determined with FTIR-spectroscopy. The measured H2O content of ~5.7 wt.% at 200 MPa and 1123 K is in good agreement with previous results of Schmidt and Behrens (2008).In contrast, the samples hydrated at P
Climate impact on phytoremediation efficacy by the Cd/Zn hyperaccumulator Arabidopsis halleri in heavy metal contaminated agricultural soils
2024-03-11

Soil and plant health are major drivers of food production. Heavy metals are present in agricultural soils and their concentrations have been increasing due to anthropogenic activities. When toxic elements reach harmful concentrations in soils and become available, they adversely affect the environment, plant performance and consequently, crop production. Our group has shown that solubility of the toxic and non-biodegradable element Cd is expected to increase in agricultural soils under IPCC-projected climatic conditions likely for the year 2100. This increased mobility of the toxic Cd potentially enhances its transfer into crops, causing a threat for agricultural production. By contrast to agricultural crops, the heavy metal hyperaccumulating plants possess physiological traits that allow them to tolerate and accumulate high concentrations of heavy metals without exhibiting toxicity symptoms. Due to these traits the hyperaccumulators show great potential for phytoremediation, but the impact of climate change on their efficacy to remove heavy metals from the soil and translocate them to aboveground tissues is still unknown. We conducted greenhouse experiments growing A. halleri on five agricultural soils that vary in Cd contents ranging from 0.07 to 14 mg kg-1 dry soil. Temperature and atmospheric CO2 concentration were controlled during the experiments, so that today&amp;#8217;s ambient climate was compared to future climate with +4&amp;#176;C and doubled atmospheric CO2 concentration. Cd accumulation in aerial parts was higher under future climatic conditions compared to plants grown under today&amp;#8217;s climate. However, the metal transfer from soil to roots and from roots to shoots depended on the combination of soil biogeochemical processes as well as plant growth and physiology. If the soil had a Cd content between 0.1 and 0.5 mg kg-1 dry soil, hyperaccumulation might not be triggered, even if the mobility of Cd was still higher under future climatic conditions. On the other hand, despite that high concentrations of soil Cd stimulated metal accumulation, simultaneous presence of high content of other elements, such as Pb that is ultimately toxic to this species, negatively impacted the efficacy of Cd phytoextraction due to the increased plant stress. For soils with Pb contents that were not toxic and Cd concentrations above 0.5 mg kg-1 dry soil, in combination with future climatic conditions, Cd availability as well as Cd translocation and transfer from soil to root were affected, increasing phytoextraction. Our results indicated that translocation towards the shoots and a potential high efficacy of phytoextraction by A. halleri may be triggered by climate change mainly in soils with moderate Cd content. Under such growth conditions, phytoremediation could be considered as a feasible option to reduce mobile Cd fractions by using metal hyperaccumulators as cover crops in agricultural ecosystems.
Learn From Your First Coursemate? The Impact of Joint Course Enrollments on Student Performance and Major Choice
2024-03-11

This study investigates first-year co-enrollment networks and their effect on the final college GPA and major switching. This study uses data from one cohort of students in a large public research university in the U.S. (N = 4,661) and applies a novel method of incorporating student co-enrollment network characteristics based on the nearest 2, 4, 8, and 16 neighbors. We found that accounting for the co-enrollment structure improves model fit, reaching a ceiling at around eight neighbors. Utilizing regression models, we found that students’ final GPA was not associated with the demographic characteristics of first-year coursemates but with their first-year college GPA. Moreover, citizenship status, performance and major of first-year coursemates are associated with major changes.
Fault Detection in Solar Thermal Systems using Probabilistic Reconstructions
2024-03-11

As heating is the largest factor of Greenhouse gases in the household sector, it shouldbe the focus of our decarbonisation efforts. Solar Thermal Systems (STS), which provideheat based on solar energy, are a promising technology in this regard. However, STSare prone to faults due to improper installation, maintenance, or operation, often leadingto a substantial reduction in efficiency, damage to the system, or even an increase inenergy cost. As individual monitoring is economically prohibitive for small-scale systems,automated monitoring and fault detection should be used to address this issue.We propose a data-driven neural network approach for fault detection in small-scaleSTS, utilising probabilistic reconstructions from a long short-term memory (LSTM) basedVariational Autoencoder (VAE). Key factors in our approach are generalising from faultlessdata to previously unseen systems and an anomaly score derived from an ensemble ofreconstructions. We apply this to an operational dataset provided by our industry partner,which includes systems with different types of faults.Our results show that our model can detect faults in STS with comparable performanceto the state-of-the-art expert-based system used by our industry partner. Furthermore, ourmodel can detect previously undetected faults, specifically those resulting from unexpectedbehaviour in the control software or behaviours that were entirely unexpected and notconsidered in the expert-based system. Thus, a combination of our model and the expert-based system covers a broader range of faults than either system and is proposed forfurther use in the industry partner&amp;#8217;s application. Additionally, other providers without afunctioning expert-based system could build upon our work to get a minimal viable productfor fault detection in STS, purely based on data from existing systems and without theneed to install additional sensors or domain-specific knowledge.
Intrinsic potential and activity of nitrate turnover examined for different hydrogeological aquifer settings
2024-03-11

Nitrate (NO3-) is one of the most serious contaminants in groundwater, frequently deteriorating water quality and groundwater use as drinking water. Nitrate can, at specific environmental conditions, be removed within the subsurface environment via natural biogeochemical processes, such as denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Traditionally, research has concentrated on the NO3- attenuation potential and microbial activity in groundwater, largely overlooking an aquifers&amp;#8217; sediment matrix as a reaction contributor. We hypothesize that the sedimentary deposits host the major potential for NO3- reduction, carrying the majority of microorganisms as well as different sources of electron donors. Moreover, diverse hydrogeological settings harbor different sources and varying amounts of electron donors such as reduced iron minerals and organic matter. Therefore, subsurface physicochemical heterogeneity, determined by sedimentology, controls the potential of an aquifer to reduce nitrate. We hypothesize that locations where physicochemical conditions favor NO3- reduction, we may expect microbes involved in these processes to be more abundant and highly active, leading to a fast NO3- removal from groundwater.Here, we present results from temperature-controlled (12&amp;#176;C) batch incubations and flow-through experiments conducted over several months using fresh sediments from an alluvial, tufaceous unconfined aquifer, with embedded peat layers, in an agricultural landscape in southwest Germany. Batch experiments received an addition of NO3- of 50 mg L&amp;#8211;1. Sediment columns were supplied with nitrate-spiked groundwater collected from the site at a maximum inlet concentration of 150 mg L&amp;#8211; and run in continuous injection mode. Batch experiments showed a gradual decrease in the initially high hydrogen sulfide (H2S) concentration, becoming undetectable after Day 7, compared to an untreated control, which revealed a slow conversion of HS-. These preliminary findings indicate a strong autotrophic denitrification with NO3- reduction coupled to aqueous HS- oxidation. In contrast to nitrate, NH4+ concentrations remained stable in all experiments. In the column experiments, the sediment exhibited a substantial NO3- reduction capacity in the early phase but rapidly declined with time. We hypothesize that a dual contribution to denitrification via easily bioavailable electron donors in the groundwater followed by slower denitrification coupled to organic matter in the sediment matrix is responsible for the observed dynamics. Our ongoing experiments, including groundwater and sediments from other, hydrogeologically different aquifers, will dissect the individual redox processes and key microorganisms involved in turnover of prominent nitrate and carbon species in the context of different hydrogeological settings.&amp;#160;
Minimizing the uncertainty in shallow borehole-temperature logging
2024-03-11

The temperature distribution through the ice sheet is a record of past climate changes. This allows reconstructing the past surface temperature history from the vertical temperature profile measured in a borehole (&amp;#8216;borehole palaeothermometry&amp;#8217;). Such a reconstruction from the inversion of the heat advection-diffusion equation is independent from the analysis of oxygen isotopes in the ice but requires high-precision measurements of the borehole-temperature on the milli-Kelvin level.&amp;#160;The precision and accuracy of the measurements is influenced by the spatial and temporal (seasonal to multi-hour) variations of the borehole temperature, the influence of the measurement setup (disturbance of the temperature profile from the borehole or snow pit drilling), the heat transfer between the ice/snow and the sensor as well as the uncertainty of the measurements (depth uncertainty and sensor precision and accuracy). &amp;#160;Here, we report on our efforts to quantify these uncertainties of near surface (10m) firn and shallow (~200m) borehole temperature measurements using a newly developed winch-based borehole measurement system as well as stationary chains of borehole/firn temperature sensors at replicate sites near the EDML drilling site, Antarctica.
Folded ice in the upper North East Greenland Ice Stream reveal timing of the onset of streaming
2024-03-11

Only a few localised ice streams drain most ice from the Greenland Ice Sheet. Thus, understanding ice stream behaviour and their temporal variability is crucially important to predict future sea-level change. The interior trunk of the 700 km-long North-East Greenland Ice Stream (NEGIS) is remarkable for the lack of any clear bedrock channel to explain its presence. Here we use isochronous radar reflections from an airborne radar survey as passive tracers of ice deformation. We present the first-ever 3-dimensional analysis of folding and advection of stratigraphic horizons within an ice stream, which shows that the localised flow and shear margins in the upstream part were fully developed only ca. 2000 years ago. This indicates that this type of streaming in the interior of an ice sheet can be triggered on short time scales.
Evaluation of opportunities to characterize and monitor moisture in the unsaturated zone above the Western Mountain Aquifer
2024-03-11

The GRaCCE project (Groundwater Recharge and Climate Change Effects - Quantification of resilience of water resources in carbonate aquifers to drought conditions) aims to develop process-based integrated and data-driven surrogate methods for determining groundwater recharge and predicting droughts in order to support water management in semi-arid regions such as Israel, Palestine and Jordan. Previous studies have shown that the thick vadose zones (several hundred meters) prevalent in the region can be relevant for water management as long-term reservoirs and, if considered as a dynamic water resource, can contribute to mitigating supply shortages during long-term droughts. In order to evaluate this water resource, it is necessary to characterize and monitor the moisture distribution in the vadose zone. In principle, borehole- and surface-based geophysical methods as well as remote sensing data can be used for this purpose. In order to assess the possibilities of the various methods for the specific site conditions of the Western Mountain Aquifer, the water balance of the area was investigated for the period from 1950 to 2020 using a double permeability variably saturated HydroGeoSphere model. Moreover, the distribution of soil moisture content at four intervals up to a cumulative depth of two-meter was inspected utilizing FLDAS2 NASA daily dataset. The temporal development of vertical moisture profiles was extracted from the HydroGeoSphere and FLDAS2 models for some selected locations. The profiles show a strong &amp;#8220;intra-annual variation&amp;#8221; at soil level which is strongly dampened by a depth two meter. This variability is generally not observed in higher depth profiles, as generated by HydroGeoSphere, where the shift from wet to dry periods made some &amp;#8220;inter-annual variation&amp;#8221; of moisture content. This result further supports the former studies claiming the importance of vadose zone on regulation of drought periods at aquifer level.&amp;#160;Moreover, based on this assessment, a site-specific initial assessment of the suitability of the measurement methods such as cosmic ray neutron sensing, ground penetrating radar, resistivity measurements, nuclear magnetic resonance and remote sensing was carried out.
Simulation-Based Inference of Surface Mass Balance of Antarctic Ice Sheets
2024-03-11

Uncertainties in surface mass balance (SMB) have the potential to significantly impact modelled ice thickness and ice-flow dynamics. A common approach is to reconstruct the surface mass balance history from the internal ice stratigraphy as imaged by radar. Particularly for intermediate and deeper layers, this requires accounting for deformation by ice flow using ice-dynamic forward models in an inverse framework. Numerous approaches to do so exist, but many of them are tailored to specific stratigraphy datasets and do not include uncertainties.Previous work used simulation-based inference (SBI) to infer the SMB rates of steady state ice shelves, solving velocities using the shallow shelf approximation [1]. The approach not only estimates the spatially varying SMB field but also their uncertainties. We adapt this framework to infer SMB on grounded ice, where flow is dominated by internal deformation rather than longitudinal stretching. The forward model used in this study calculates velocities by solving the shallow ice approximation. The resulting velocities are used as input to an isochronal tracer scheme which calculates the stratigraphy of the ice [2]. Initial testing of our method is conducted on an idealized ice sheet, namely the Vialov profile. In future work, we aim to infer for the SMB history along a radar transact of Derwael Ice Rise in East Antarctica, where internal stratigraphy data is available. Our method provides a new uncertainty aware approach to estimate the SMB field on grounded ice.&amp;#160;[1] Moss et al.: Simulation-Based Inference of Surface Accumulation and Basal Melt Rates of an Antarctic Ice Shelf from Isochronal Layers (2023).[2] Born: Tracer transport in an isochronal ice-sheet model (2017).
In-situ Saharan dust observations over the Eastern Mediterranean with an uncrewed aircraft system
2024-03-11

The Saharan desert is the main source of mineral dust in the atmosphere, and its presence in the air can have a significant impact on the solar radiation budget. In evaluating the radiative effect of airborne mineral dust, aerosol charge may be a critical factor. This space charge and its relationship to particle concentrations is not taken into account by current model simulations, and such in-situ measurements are hardly available. In this work, a novel sensor network equipped on an uncrewed aircraft system (UAS) of type MASC-3 was employed for vertical profiling of Saharan dust particle concentrations, meteorological (temperature, relative humidity and wind field) parameters and turbulent kinetic energy (TKE), during a dust event that occurred in Orounda, Cyprus in April 2022. The MASC-3 performed profiles up to 3000 m altitude, and identified the vertical extent of the dust cloud, which was located between 1900 and 2500 m. We were able to capture the evolution of the event over several days, and additional numerical simulation and remote sensing observations verify the results. During the first day of measurements, when dust load was the highest, charge data from the MASC-3 also allowed for investigation of aerosol concentrations and dust electrification. For the first time, this innovative sensor system provided in-situ UAS measurements of the aforementioned quantities and described the dust event in detail, and with high resolution. Considerations on aircraft charging, the effect of turbulent levels and local meteorology, on the space charge / aerosol data collected by the MASC-3, as well as probing Saharan dust events more generally, are elaborated for further related research.
ApRES observations of ice fabric in Greenland: From a climatic transition in the North to a potential historical ice stream remnant in the South
2024-03-11

The crystal orientation fabric (COF) of ice sheets, characterized as the net alignment of ice crystals, can contain a record of past ice sheet dynamics and potentially climatic conditions. In turn, the COF significantly influences ice viscosity, thus impacting present-day ice deformation and flow velocities. Due to its dielectric properties, anisotropic COF can be detected with polarimetric radar measurements, including Autonomous phase-sensitive Radio-Echo Sounders (ApRES).Here, we present findings from polarimetric ApRES measurements conducted at Camp Century North-West Greenland, and two sites in Southwest Greenland: Dye-2 and KAN-U. At Camp Century, the ApRES measurements indicate some COF anisotropy throughout the ice column, with a distinct boundary at the depth of the Holocene-Wisconsin ice transition, previously identified in a nearby ice core. We investigate the origin of this boundary in the ApRES data, and whether such signatures can be used to identify glacial-interglacial transitions from polarimetric radar data.At both sites in Southwest Greenland, the signal is strongly attenuated and falls below the noise level beyond 500 m depth, likely due to significant scattering within a heterogeneous firn column. However, Dye-2 exhibits strong COF anisotropy in the uppermost 100-500 m of the ice column, despite the region&amp;#8217;s slow ice flow. Conversely, KAN-U displays no evidence of&amp;#160; COF anisotropy. We investigate causes of the peculiar localized anisotropy at Dye-2, hypothesizing it as a residual imprint of a historic fast flowing, far inland-reaching ice stream.