bluuebunny/crossref_metadata_2025 huggingface dataset:
Why go for a computation-based approach to cognitive representation
Authors: Coelho Mollo Dimitri
Published: March 2021

An influential view in (philosophy of) cognitive science is that computation in cognitive systems is semantic, conceptually depending on representation: to compute is to manipulate representations. I argue that accepting the non-semantic teleomechanistic view of computation lays the ground for a promising alternative strategy, in which computation helps to explain and naturalise representation, rather than the other way around. I show that this computation-based approach to representation presents six decisive advantages over the semantic view. I claim that it can improve the two most influential current theories of representation, teleosemantics and structural representation, by providing them with precious tools to tackle some of their main shortcomings. In addition, the computation-based approach opens up interesting new theoretical paths for the project of naturalising representation, in which teleology plays a role in individuating computations, but not representations.
Differenzialdiagnose expansiver Osteolysen im Kiefer
Authors: Baumhoer D.
Published: March 2021

Expansive Osteolysen im Kiefer entsprechen nicht immer odontogenen Zysten, weshalb bei nicht eindeutiger Konstellation eine bioptische Abklärung erfolgen sollte. Neben gut- und bösartigen odontogenen Tumoren kommt differenzialdiagnostisch auch eine Reihe von Knochentumoren und Pseudozysten in Betracht, deren charakteristische Verteilung im Kiefer sowie typische Altersgipfel bei der Einteilung helfen können. Für eine verlässliche Diagnostik ist auch die Kenntnis der Bildgebung und Klinik (Anamnese, Symptomatik, klinischer bzw. intraoperativer Befund) unerlässlich. Zusätzlich stehen neue und innovative molekulare Marker und Analyseverfahren zur Verfügung, die die Diagnostik zusätzlich objektivieren können. Dieser Beitrag gibt eine Übersicht über rein osteolytische Kieferläsionen und ihre Differenzialdiagnosen.
Impact of Foliar Application of Various Forms of Silicon on the Chemical Composition of Sugar Beet Plants
Authors: Artyszak Arkadiusz , Kondracka Małgorzata , Gozdowski Dariusz , Siuda Alicja , Litwińczuk-Bis Magda
Published: March 2021

The effect of marine calcite, a mixture of ortho- and polysilicic acid as well as orthosilicic acid applied as a foliar spray on the chemical composition of sugar beet leaves in the critical phase of nutrient supply (beginning of July) but also leaves and roots during harvest time in 2015–2016, was studied. The content of silicon in the leaves ranged from 1.24 to 2.36 g kg−1d.m. at the beginning of July, 3.85–5.34 g kg−1d.m. during harvest and 2.91–4.20 g kg−1d.m. in the roots. The foliar application of silicon caused a significant increase in the content of magnesium and calcium in leaves (in July) as compared to the control. The sugar beet consumes approx. 75 kg Si ha−1, which is almost 3.5 times more than P and 20% more than Mg thus proving its importance for its species. About 70% of the silicon taken up by sugar beet is stored in roots and 30% in leaves. The pure sugar yield is most favorably influenced by two- and threefold foliar application of the product containing silicon in the form of orthosilicic acid stabilized with choline, and a threefold mixture of ortho- and polysilicic acid. The increase in the pure sugar yield is not the result of a change in the chemical composition of sugar beet plants, but their more efficient functioning after foliar application of silicon under stress conditions caused by water shortage.
Impact of COVID-19 outbreak on hospital admissions and outcome of acute coronary syndromes in a single high-volume centre in southeastern Europe
Authors: Petrović M. , Milovančev A. , Kovačević M. , Miljković T. , Ilić A. , Stojšić-Milosavljević A. , Golubović M.
Published: March 2021

Background

As coronavirus disease 2019 (COVID-19) has reached pandemic status, authors from the most severely affected countries have reported reduced rates of hospital admissions for patients with acute coronary syndrome (ACS).

Aim

The aim of the present study was to investigate the influence of the COVID-19 outbreak on hospital admissions and outcomes in ACS patients in a single high-volume centre in southeastern Europe.

Methods

This retrospective observational study aimed to investigate the number of hospital admissions for ACS, clinical findings at admission, length of hospitalisation, major complications and in-hospital mortality during the COVID-19 outbreak and to compare the data with the same parameters during an equivalent time frame in 2019. For the ST-elevated myocardial infarction (STEMI) subgroup of patients, changes in ischaemic times were analysed as well.

Results

There was a significant reduction of 44.3% in the number of patients admitted for ACS during the COVID-19 outbreak when compared with the same period in 2019 (151 vs 271; 95% confidence interval 38.4–50.2,p < 0.01) with a higher mortality rate (13.2% vs 7.2%,p = 0.03). In 2020, patients with non-ST-elevated myocardial infarction presented more often with acute heart failure (3.3% vs 0.7%,p = 0.04). During the COVID-19 outbreak, we observed increases in the total ischaemic time (303 ± 163.4 vs 200.8 ± 156.8 min,p < 0.05) and door-to-balloon time (69.2 ± 58.4 vs 50.5 ± 31.3 min,p < 0.01) in STEMI patients.

Conclusions

These findings should increase the awareness of morbidity and mortality related to missed or delayed treatment of ACS among the public and the healthcare services.
Erratum to: Interactions of molten salts with cathode products in the FFC Cambridge Process
Authors: Chen George Z.
Published: March 2021

The copyright information of the print version for this article unfortunately is not the same with that of the online version. The copyright information of the online version is right, which is “© The Author(s) 2020”.
Clinical outcomes and functional analysis of third space robotic and endoscopic cooperative surgery versus laparoscopic wedge resection for gastric submucosal tumours: a propensity score-matched study
Authors: Shi Feiyu , Liu Gaixia , Sun Qi , zhang Haowei , Wu Hongtao , Xue Xiaobin , Li Yingchao , She Junjun
Published: March 2021

Third space robotic and endoscopic cooperative surgery (TS-RECS) is a novel minimally invasive surgery for resecting gastric submucosal tumours (GSMTs), which could accomplish the completely oncological curability and maximal functional preservation. This study investigated the clinical outcomes and gastrointestinal function after TS-RECS versus laparoscopic wedge resection (LWR) for GSMTs. This was a single-centre retrospective study that included 130 patients with GSMTs who underwent LWR or TS-RECS from 2013 to 2019. To overcome selection biases, we performed propensity score matching (1:1) using seven covariates that could impact the group assignment and outcomes. Then, the clinical outcomes and gastrointestinal function in the LWR and TS-RECS groups were compared in a matched cohort. Among the 130 enrolled patients, 96 patients underwent LWR, and 34 underwent TS-RECS and were matched into 30 patients for each group. There was no significant difference in the operation time between the two groups (P = 0.543). However, the TS-RECS group had significantly less blood loss (20,5–100 vs 95,10–310 ml, P < 0.0001) and better postoperative recovery in terms of time to oral intake (2,2–4 vs 3,2–6 days, P < 0.0001) and postoperative hospital stay (5,4–10 vs 8.5,5–16 days, P < 0.0001) than the LWR group. The severity and frequency scores of postoperative gastrointestinal symptoms in the TS-RECS group were significantly lower than those in the LWR group. The median follow-up period was 24 months (10–60 months) in the LWR group and 18 months (10–27 months) in the TS-RECS group, and there was in total a single recurrence in the LWR group. TS-RECS appears to be a technically safe and effective surgery with preservation of gastrointestinal function for resection of GSMT resection.
Three factor authentication system with modified ECC based secured data transfer: untrusted cloud environment
Authors: Vengala Dilip Venkata Kumar , Kavitha D. , Kumar A. P. Siva
Published: March 2021

Cloud computing (CC) is a technology that delivers its service by means of the internet. In the modern scenario, cloud storage services have gained attention. The cloud environment confronts data breaches expansively in cloud storage, which might bring about the disclosure of personal in addition to corporate data. Thus, the requirement arises for the creation of a more foremost authentication system. Customary authentication schemes depend on techniques, like Password Authentications Protocol (PAP), Challenge Handshakes Authentication Protocols (CHAP), as well as One-Time Pads (OTP), which are often susceptible to malevolent attacks as well as security threats. To shun such issues, this paper proposed a Modified ECC centred secure data transfer and a ‘3’-factor authentication scheme in the untrusted cloud environment. The proposed work comprises ‘3’ steps: authentication, data compression, and safe data transfer. In the authentication phase, the SHA-512 algorithm along with CCP is utilized. After that, the user-uploaded data is compressed utilizing CHA on the server-side. Next, MECC encrypts the compressed data, and then, safely uploaded it to the cloud server (CS). In the investigational appraisal, the proposed work is contrasted with the prevailing methods. The outcomes proved that the proposed work renders better security than the prevailing methods.
Evaluation of parameterized quantum circuits: on the relation between classification accuracy, expressibility, and entangling capability
Authors: Hubregtsen Thomas , Pichlmeier Josef , Stecher Patrick , Bertels Koen
Published: March 2021

An active area of investigation in the search for quantum advantage is quantum machine learning. Quantum machine learning, and parameterized quantum circuits in a hybrid quantum-classical setup in particular, could bring advancements in accuracy by utilizing the high dimensionality of the Hilbert space as feature space. But is the ability of a quantum circuit to uniformly address the Hilbert space a good indicator of classification accuracy? In our work, we use methods and quantifications from prior art to perform a numerical study in order to evaluate the level of correlation. We find a moderate to strong correlation between the ability of the circuit to uniformly address the Hilbert space and the achieved classification accuracy for circuits that entail a single embedding layer followed by 1 or 2 circuit designs. This is based on our study encompassing 19 circuits in both 1- and 2-layer configurations, evaluated on 9 datasets of increasing difficulty. We also evaluate the correlation between entangling capability and classification accuracy in a similar setup, and find a weak correlation. Future work will focus on evaluating if this holds for different circuit designs.
Molecular mediators of breast cancer metastasis
Authors: Yeeravalli Ragini , Das Amitava
Published: March 2021

Breast cancer has the highest incidence rate of malignancy in women worldwide. A major clinical challenge faced by patients with breast cancer treated by conventional therapies is frequent relapse. This relapse has been attributed to the cancer stem cell (CSC) population that resides within the tumor and possess stemness properties. Breast CSCs are generated when breast cancer cells undergo epithelial-mesenchymal transition resulting in aggressive, highly metastatic, and invasive phenotypes that exhibit resistance towards chemotherapeutics. Metastasis, a phenomenon that aids in the migration of breast CSCs, occurs through any of three different routes: hematogenous, lymphatic, and transcoelomic. Hematogenous dissemination of breast CSCs leads to metastasis towards distant unrelated organs like lungs, liver, bone, and brain causing secondary tumor generation. Activation of metastasis genes or silencing of metastasis suppressor genes often leads to the advancement of metastasis. This review focuses on various genes and molecular factors that have been implicated to regulate organ-specific breast cancer metastasis by defying the available therapeutic interventions.
Mental Health and the Field Research Team
Authors: Eifling Kurt P.
Published: March 2021

Due to the intellectual, physical, and emotional demands of field research, those doing this work need to strategies to monitor and maintain their own mental health before, during, and after a field season. Moreover, they should have a framework for supporting their colleagues. This review article will present a framework for assessing the mental health hazards and the reactions, both positive and negative, to fieldwork. First, it will use U.S. epidemiology to show that most field teams are at risk. Second, it will frame the field season both as a workplace and wilderness exposure event and discuss the elements of the field research environment that can be therapeutic for some but toxic for others. Third, it will discuss the psychological impacts of travel and reintegration as they are pertinent to the practice of archaeology. Research will be presented in order to guide evidence-informed policies for the field research team to improve the mental-health readiness and resiliency of the research team. Last, it will provide guidance on how to manage the anxiety caused by separating from social media platforms.
The Paradox of Planning: Agriculture, Schooling, and the Unresolvable Uncertainty of Ideal Family Size in Rural Sierra Leone
Authors: Bolten Catherine E. , Marcantonio Richard
Published: March 2021

Post-war Sierra Leone has experienced a population explosion that has raised questions among rural farmers about the relationship between family size and poverty. Agricultural decline and the high cost of schooling are not prompting parents to articulate a desire for smaller families; rather, they highlight that the uncertainty around articulating the “right” number of children is unresolvable because the ability to send children to school is predicated on increasing agricultural outputs that decline precisely because population pressure has reduced soil fertility. Bolten and Marcantonio conclude that this renders family size the heart of a paradox, where there is no optimal number of children.
Steering a thermally activated micromotor with a nearby isothermal wall
Authors: Poddar Antarip , Bandopadhyay Aditya , Chakraborty Suman
Published: March 2021

Selective heating of a microparticle surface had been observed to cause its autonomous movement in a fluid medium due to self-generated temperature gradients. Here, we theoretically investigate the response of such an auto-thermophoretic particle near an isothermal planar wall. We derive an exact solution of the energy equation and employ the Lorentz reciprocal theorem to obtain the translational and rotational swimming velocities in the creeping-flow limit. We report fixed points for vertical movement of the micromotor for its specific orientations relative to the wall. The critical wall gap for fixed points shows unique non-monotonic dependence on the metallic coating coverage on the particle. Also, the micromotor trajectories can be switched either from wall-bound sliding or stationary state to escape from the near-wall zone by tuning the particle and the surrounding fluid pair thermal conductivity contrast. The scenario holds several exclusive distinguishing features from the otherwise extensively studied self-diffusiophoresis phenomenon near an inert wall, despite obvious analogies in the respective constitutive laws relating the fluxes with the gradients of the concerned forcing parameters. The most contrasting locomotion is the ability of a self-thermophoretic micromotor with a large heated cap to migrate towards the wall even if it is initially directed away from the wall. During the stationary states of swimming, the cold portion on the micromotor surface faces away from the wall under all conditions. Such unique aspects hold the potential of being harnessed in practice towards achieving intricate control over the autonomous motion of microparticles in thermally regulated fluidic environments.
Dietary diversity and associated factors among HIV-positive adults attending the anti-retroviral therapy clinic at Felege Hiwot Comprehensive Specialized Hospital, Northwest Ethiopia: a cross-sectional study
Authors: Said Hiwot Ahmed , Tsega Gebeyehu , Tesfaye Tadesse Dagget
Published: March 2021

The aim of the study was to assess dietary diversity (DD) and associated factors among human immune deficiency virus (HIV)-positive adults attending the anti-retroviral therapy (ART) clinic at Felege Hiwot Comprehensive Specialized Hospital (FHCSH) in Northwest Ethiopia. An institution-based cross-sectional study was conducted at FHCSH in 2019. A systematic random sampling technique was employed to select 352 study subjects. Data were collected using an interviewer-administered questionnaire and chart review. Statistical Package for the Social Science version 26 was used for analysis. A simple and multivariable binary logistic regression was used to determine associated factors. Two hundred and nine (59⋅4 %) adults had consumed a diversified diet. The mean individual DD score was 3⋅86 ± 1⋅18. Self-employment status (adjusted odd ratio (AOR): 4⋅60; 95 % confidence interval (CI): 1⋅72, 12⋅27), quintiles of wealth index (the second (AOR: 4⋅33; 95 % CI: 1⋅72, 10⋅89), middle (AOR: 4⋅40; 95 % CI: 1⋅71, 11⋅31), fourth (AOR: 6⋅60; 95 % CI: 2⋅36, 18⋅48) and the highest quintiles (AOR: 9⋅45: 95 % CI: 3⋅34, 26⋅77), the last CD4 count 200–349 cells/mm3 (AOR: 8⋅08; 95 % CI: 2⋅93, 22⋅23), those who took first-line ART regimen drugs (AOR: 4⋅49; 95 % CI: 2⋅19, 9⋅21), subjects who did not take co-trimoxazole prophylaxis (AOR: 6⋅36; 95 % CI: 2⋅54, 15⋅88), those who had nutritional counselling at a health institution (AOR: 2⋅36; 95 % CI: 1⋅08, 5⋅16), had no food preference (AOR: 2⋅42; 95 % CI: 1⋅14, 5⋅13) and a food-secure household (AOR: 3⋅51; 95 % CI: 1⋅85, 6⋅67) were associated factors of DD among adults on ART. This study exhibited that the DD status among adults attending the ART clinic was below two-thirds. Health institutions and health professionals working at ART clinics shall strengthen their efforts to sustain the nutritional counselling service and ART adherence at health institutions and encourage the patients to avoid food preference for their meal. It is vital to ensure the household food security of adults on ART.
Late Pleistocene–Holocene stress in the South American intraplate evidenced by tectonic instability in central Amazonia
Authors: Rossetti Dilce F. , Bezerra Francisco H. R. , Valeriano Márcio M. , Molina Eder Cassola
Published: March 2021

Documenting neotectonic instabilities and determining the style and time of deformation in the vast and difficult to access central Amazonia region is challenging. We focus on these issues by investigating a large area of the Negro River drainage basin, applying morphostructural analysis based on synthetic aperture radar data. The digital elevation models of the C-band Shuttle Radar Topography Mission and the L-band Protection System of Amazonia were used as the database. We also used subsurface magnetic information from the Earth Magnetic Anomaly Grid global model to validate the morphostructures. The results revealed NW-oriented morphostructural lineaments bounding multiple depositional valley fills. These were extensively fragmented to form regularly distributed en échelon rectangular blocks commonly offset horizontally by several kilometers. Strike-slip faults and oblique, either normal or reverse, faults are present. These structures were reactivated along the main NE- and SW-oriented regional structural trends due to N-S-oriented horizontal compression and E-W-oriented horizontal extension in the late Pleistocene and Holocene. The extensive neotectonic faulting results from the interplay of plate motion and Andean uplifting since the late Pleistocene, combined with local stresses.
Shining a light on parasite behaviour: daily patterns ofArgulusfish lice
Authors: Hunt Rhi , Cable Jo , Ellison Amy
Published: March 2021

Parasites display a wide range of behaviours that are frequently overlooked in favour of host responses. Understanding these behaviours can improve parasite control through a more precise application or development of new behaviour-based strategies. In aquaculture fish lice are an ongoing problem, infections reduce fishery production and control options are limited. Fish lice are distinct in their ability to survive and swim off hosts, allowing the transmission to multiple fish hosts across their lifespan. Here we assessed the off-host behaviour ofArgulus foliaceus(a freshwater fish louse) and observed a diurnal rhythmical pattern in their behaviour. This pattern was lost when lice were exposed to constant darkness, indicating that the behaviour is not endogenously driven. Males were consistently active in light with reduced activity in darkness. In contrast, females were active during light and dark phases with peak activity at the start of dark periods.A. foliaceuswas also strongly attracted to a light stimulus, preferring white- and blue-coloured lights over green- or red-coloured lights. Light is a strong driver of fish louse activity and could be used to trap parasites. Aquaculture light regimes could also be altered to reduce parasite attraction and activity.
Impact of Atmospheric Deposition on Carbon Export to the Deep Ocean in the Subtropical Northwest Pacific
Authors: Xiu Peng , Chai Fei
Published: March 2021

The impact of atmospheric deposition on deep‐ocean carbon export in the subtropical Northwest Pacific remains poorly evaluated. Using sediment trap data and a newly improved biogeochemical model, we show that iron deposition in winter and spring and nitrogen deposition in summer and fall are important drivers for the seasonal variability of deep‐ocean particulate organic carbon (POC) export flux. Nitrogen deposition can stimulate pico‐plankton growth in summer and fall, which leads to increases of microzooplankton and mesozooplankton. The increase of mesozooplankton exerts higher grazing pressure on diatoms in winter and early spring, which then reduces deep‐ocean POC export due to the reduction of ballasting mineral of opal. Iron deposition only affects the region in winter and spring when nitrogen is not a limiting factor for phytoplankton growth; and it can increase deep‐ocean POC export by stimulating diatom growth and opal production.
Non‐Monotonic Response of the Climate System to Abrupt CO2 Forcing
Authors: Mitevski Ivan , Orbe Clara , Chemke Rei , Nazarenko Larissa , Polvani Lorenzo M.
Published: March 2021

We explore the climate system response to abrupt CO2 forcing, spanning the range 1× to 8×CO2, with two state‐of‐the‐art coupled atmosphere‐ocean‐sea‐ice‐land models: the NASA Goddard Institute for Space Studies Model E2.1‐G (GISS‐E2.1‐G) and the Community Earth System Model (CESM‐LE). We find that the effective climate sensitivity is a non‐monotonic function of CO2 in both models, reaching a minimum at 3×CO2 for GISS‐E2.1‐G, and 4×CO2 for CESM‐LE. A similar non‐monotonic response is found in Northern Hemisphere surface temperature, sea‐ice, precipitation, the latitude of zero precipitation‐minus‐evaporation, and the strength of the Hadley cell. Interestingly, the Atlantic meridional overturning circulation collapses when non‐monotonicity appears and does not recover for larger CO2 forcings. Analyzing the climate response over the same CO2 range with slab‐ocean versions of the same models, we demonstrate that the climate system’s non‐monotonic response is linked to ocean dynamics.
Lower Tropospheric Processes: A Control on the Global Mean Precipitation Rate
Authors: Hendrickson Jacob M. , Terai Christopher R. , Pritchard Michael S. , Caldwell Peter M.
Published: March 2021

The spread in global mean precipitation among climate models is explored in two ensembles using the complementary perspectives of surface evaporation and energy budgets. Models with higher global mean precipitation have stronger oceanic evaporation, driven by drier near‐surface air. The drier surface conditions occur alongside increases in near‐surface temperature and moisture at 925 hPa, which point to stronger boundary layer mixing. Correlations suggest that the degree of lower tropospheric mixing explains 18%–49% of the intermodel precipitation variance. To test this hypothesis, the degree of mixing is indirectly varied in a single‐model experiment by adjusting the relative humidity threshold that controls low‐cloud fraction. Indeed, increasing lower tropospheric mixing results in more global mean precipitation. Energetically, increased precipitation rates are associated with more downwelling longwave radiation to the surface and weaker sensible heat fluxes. These results highlight how lower‐tropospheric processes must be better constrained to reduce the precipitation discrepancy among climate models.
Thermal Modeling of the Lunar Regolith at the Chang'E‐4 Landing Site
Authors: Lin Honglei , Li Shuai , Lin Yangting , Liu Yang , Wei Yong , Yang Wei , Yang Yazhou , Hu Sen , Wu Xing , Xu Rui , Li Chunlai , He Zhiping
Published: March 2021

Accurate assessments of surface temperatures on the Moon are important for understanding the physical properties of the lunar surface regolith and thermal effects on the reflectance spectra beyond 2 μm. The local time resolved spectral measurements of the same region were used to estimate the surface temperature at the Chang'E‐4 landing site. The results show that the surface temperatures at the landing site at lunar local time 14:28–14:41 are 346 ± 8 K. The spectral absorptions at ∼2 μm of the lunar surface are overestimated without sufficient thermal removal, and consequently may have resulted in overestimation of pyroxene and/or glasses at the landing site. The results play a foundation for correcting thermal effects of reflectance data that will be acquired by Chang'E‐5 and ‐6 and possible other future Chang'E missions.
Direct Observation of Sulfate Explosive Growth in Wet Plumes Emitted From Typical Coal‐Fired Stationary Sources
Authors: Ding Xiang , Li Qing , Wu Di , Wang Xiaoyan , Li Mei , Wang Tao , Wang Lin , Chen Jianmin
Published: March 2021

The origins of atmospheric sulfate production have previously been explained by focusing on air quality models and complex chemical reaction processes. Here, we first report direct observations of sulfate production in stack plumes discharged from coal‐fired power plants, industrial boilers, and sintering plants equipped with wet desulfurization systems. Less than one third of the particulate SO42− in plumes is attributed to dust‐SO42− and SO3 measured in stacks. The SO2 aqueous‐phase oxidation process is critical in explaining the unknown sulfate formation in plume droplets with pH values ranging from 2.3 to 2.8. When the rapidly formed sulfate in wet plumes is included, a notable amount of underestimated sulfate (∼0.24 Tg in 2017) is emitted from industrial stacks in China and can partially explain the “missing sulfate” on driving most particle pollution episodes. Policy‐making targeting particulate emissions is suggested to substantially reduce sulfate emissions for further air quality improvement.
Electron‐Scale Measurements of Antidipolarization Front
Authors: Xu Yin , Fu Huishan , Cao Jinbin , Liu Chengming , Norgren Cecilia , Chen Zuzheng
Published: March 2021

Antidipolarization fronts (ADFs), usually formed at the leading edge of the tailward reconnection jets in the Earth's magnetotail, are characterized by sharp enhancements of southward magnetic field (negative Bz). The fine structures at electron scale of the ADFs have not been studied so far, due to instrumental limitations and large separation of previous spacecraft. Here, we use the Magnetospheric Multiscale mission to investigate the structure and dynamics of an ADF at electron scale. We find an intense current at the ADF, with the parallel current carried by a fast electron jet and the perpendicular current contributed by ion flow. Strong electric fields are found at the front and balanced by Hall term. The ion current leads to strong energy conversion, transforming the electromagnetic energy into particle energy. Our study makes essential steps toward understanding ADF dynamics in the magnetotail.
Jupiter's Ion Radiation Belts Inward of Europa's Orbit
Authors: Kollmann P. , Clark G. , Paranicas C. , Mauk B. , Roussos E. , Nénon Q. , Garrett H. B. , Sicard A. , Haggerty D. , Rymer A.
Published: March 2021

Jupiter is surrounded by intense and energetic radiation belts, yet most of the available in‐situ data, in volume and quality, were taken outward of Europa's orbit, where radiation conditions are not as extreme. Here, we study measurements of ions of tens of keV to tens of MeV at <10 Jupiter radii (RJ) distance to Jupiter, therefore inward of the orbit of Europa. Ion intensities drop around 6 RJ, near Io's orbit. Previous missions reported on radiation belts of tens and hundreds of MeV ions located between 2 and 4 RJ. Measurements of lower energies were not conclusive because high energy particles often contaminate the measurement of lower energy particles. Here, we show for the first time that ions in the hundreds of keV range are present and suggest that ions may extend even into the GeV range. The observation of charged particles yields information on the entire field line, not just the local field. We find that there is a region close to Jupiter where no magnetic trapping is possible. Jupiter's innermost radiation belt is located at <2 RJ, inward of the main ring. Previous work suggested that this belt is sourced by re‐ionized energetic neutral atoms coming steadily inward from distant regions. Here, we perform a phase space density analysis that shows consistency with such a local source. However, an alternative explanation is that the radiation belt is populated by occasional strong radial transport and then decays on the timescale of years.
Improved 3‐D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy
Authors: Ishise Motoko , Kato Aitaro , Sakai Shin'ichi , Nakagawa Shigeki , Hirata Naoshi
Published: March 2021

The Tokyo metropolitan area, in the Kanto region of Japan, lies on the Okhotsk plate. Historically, the city has suffered severe damage as a result of megathrust ruptures and intra‐plate earthquakes (M ≥ 7) caused by the dual subduction of the Philippine Sea (PHS) slab and the Pacific slab. To understand the unique seismotectonics of the region, we constrain the three‐dimensional (3‐D) P wave isotropic and azimuthal anisotropic velocity structure beneath the Kanto district, by applying a high‐resolution anisotropic tomography method to travel time data from a dense seismic network consisting of ∼500 stations (including the Metropolitan Seismic Observation network, MeSO‐net). The seismic structure, derived from 1,877 local earthquakes, suggests that the basement of the Okhotsk plate consists of an old accretionary zone formed when the NE Japan arc was part of the Asian continent. The anisotropy observed in the oceanic crust of the subducting PHS slab suggests the presence of a well‐developed system of bending‐related faults, oriented parallel to the axis of the Sagami Trough. We identify a low‐velocity anomaly within the PHS slab mantle, located beneath the Boso Peninsula, which has previously been interpreted as representing the overlying continental plate or the oceanic crust of the PHS slab. Lateral variations in the anisotropy structure suggest that the NE limit of the PHS slab lies farther south than previously thought. Anisotropy directions can be used to identify heterogeneities embedded in low‐velocity anomalies within the PHS slab, which have not been identified in previous studies using only isotropic velocity models.
Comment on “Increasing Rates of Carbon Burial in Southwest Florida Coastal Wetlands” by J. Breithaupt et al.
Authors: Parkinson Randall W.
Published: March 2021

In a recent study, Breithaupt et al. (2020); https://doi.org/10.1029/2019JG005349 contend observed rates of sediment and organic carbon accumulation in Southwest Florida coastal wetlands have increased in response to an acceleration in the rate of sea‐level. This, it is argued, implies the wetlands are more resilient to future sea‐level rise than previously thought and under conditions of continued acceleration, even more organic carbon will be stored. However, upon closer inspection, the study conclusions are flawed as they are based upon an inappropriate methodological approach to quantifying sediment and organic carbon accumulation rates and require an acceleration in the rate of historical (decades) sea‐level rise of which there is limited evidence and no broad consensus.
Assessing Sedimentary Detrital Pb Isotopes as a Dust Tracer in the Pacific Ocean
Authors: Erhardt Andrea M. , Douglas Grant , Jacobson Andrew D. , Wimpenny Josh , Yin Qing‐Zhu , Paytan Adina
Published: March 2021

Mineral dust particles from different source regions typically have distinct Pb isotope ratios. Theoretically, Pb isotopic composition of terrigenous minerals isolated from open‐ocean sediments should allow for dust provenance reconstructions. However, Pb isotopes of terrigenous fractions of sediments have frequently been inconsistent with expected source region signatures. This study investigates the reason(s) for offsets between the Pb isotope values of the dust component in sediment cores and those expected from source regions with focus on changes in sediment composition, sediment age, and sediment processing for analysis. Pb isotope ratios from Pacific Ocean core‐top sediments show a general delineation of the Intertropical Convergence Zone (ITCZ). Isotope mixing models support these general trends, though similarity in Pb isotope ratios of disparate source regions makes constraining specific sources challenging. Pb isotope ratios in downcore samples varied on glacial/interglacial time scales, being less radiogenic during the last glacial maximum, suggesting either a weakened ITCZ or the addition of a new, less radiogenic, source to the system. Finally, Pb isotope ratios in some source region samples yielded different Pb isotope signatures in bulk source sample than in the insoluble terrigenous fraction of the source sample, indicating that differential mineral preservation within the terrigenous component in sediments may cause offsets from source signatures. Overall, while Pb isotopes show distinct basin‐scale variations, high‐resolution spatial reconstructions require tight age controls and consistency in analytical treatment if used to define ocean sediment source regions.
Formation and Forward Propagation of the Indosinian Foreland Fold‐Thrust Belt and Nanpanjiang Foreland Basin in SW China
Authors: Yang Wen‐Xin , Yan Dan‐Ping , Qiu Liang , Wells Michael L. , Dong Jian‐Meng , Gao Tian , Zhang Zhi , Mu Hongxu , Wang Xinwen , Wang Fangyue
Published: March 2021

Orogenic growth, characterized by formation and forward propagation of fold‐thrust belts and foreland basins, is predicted by wedge models of thrust systems. The growth of the Nanpanjiang fold‐thrust belt and foreland basin system of the Indosinian orogenic belt in the southwestern South China remains poorly understood. The development of the Indosinian foreland system remains underappreciated due to few constraints on structural styles, kinematics and ages. Surface cross sections, seismic profiles and detrital zircon data are presented to address the structural styles and evolution of the Indosinian foreland system. The results reveal that the fold‐thrust belt is characterized by fault‐related folds with deeper duplexes and shallower imbricates, which yield a NNE‐SSW regional shortening magnitude of ∼36%. Our new constraints indicate that the Nanpanjiang region experienced multi‐staged thrusting during the Indosinian orogeny (D1). The D11affected the southernmost southern fold‐thrust belt, producing thick‐skinned thrusts involving Neoproterozoic basement and initiating the Nanpanjiang foreland basin. During the D12, NNE‐verging thick‐skinned thrusting continued and was followed by thin‐skinned thrusting in the northern fold‐thrust belt. Locally preserved foreland basin deposits at the northernmost Nanpanjiang Basin define D13. The progressive D14co‐axially deformed the residual basin into a wide and gentle syncline. Thus, the progressive D11to D14deformation sequence of NNE‐verging in‐sequence thrusting and foreland basin migration describe the kinematic and dynamic relationship between fold‐thrust belt and foreland basin during the Indosinian tectonic event. Indosinian D1structures were subsequently refolded by the Yanshanian tectonic event (D2), forming N‐ to NE‐striking cleavage and arcuation of D1fold axes.
A Framework for Untangling Transient Groundwater Mixing and Travel Times
Authors: Popp Andrea L. , Pardo‐Álvarez Álvaro , Schilling Oliver S. , Scheidegger Andreas , Musy Stéphanie , Peel Morgan , Brunner Philip , Purtschert Roland , Hunkeler Daniel , Kipfer Rolf
Published: March 2021

Understanding the mixing between surface water and groundwater as well as groundwater travel times in vulnerable aquifers is crucial to sustaining a safe water supply. Age dating tracers used to infer apparent travel times typically refer to the entire groundwater sample. A groundwater sample, however, consists of a mixture of waters with a distribution of travel times. Age dating tracers only reflect the proportion of the water that is under the dating range of the used tracer, thus their interpretation is typically biased. Additionally, end‐member mixing models are subject to various sources of uncertainties, which are typically neglected. In this study, we introduce a new framework that untangles groundwater mixing ratios and travel times using a novel combination of in‐situ noble gas analyses. We applied this approach during a groundwater pumping test carried out in a pre‐alpine Swiss valley. First, we calculated transient mixing ratios between recently infiltrated river water and regional groundwater present in a wellfield, using helium‐4 concentrations combined with a Bayesian end‐member mixing model. Having identified the groundwater fraction of recently infiltrated river water (Frw) consequently allowed us to infer the travel times from the river to the wellfield, estimated based on radon‐222 activities of Frw. Furthermore, we compared tracer‐based estimates of Frw with results from a calibrated numerical model. We demonstrate (i) that partitioning of major water sources enables a meaningful interpretation of an age dating tracer of the water fraction of interest and (ii) that the streambed has a major control on the estimated travel times.
Assessing the Precision of Total Contributing Area (TCA) Estimated by Flow Direction Algorithms Based on the Analytical Solution of Theoretical TCA on Synthetic Surfaces
Authors: Li Zhenya , Yang Tao , Wang Chao , Shi Pengfei , Yong Bin , Song Ying
Published: March 2021

Total contributing area (TCA) has important hydrological, geological, and geomorphological implications in digital terrain analysis. Currently, the validity of estimated TCA is challenged by the approximation error of digital elevation models (DEMs) to real‐world terrains, the choice of flow direction algorithms and the difficulty in a quantitative evaluation. To solve these problems, this work employs a range of synthetic surfaces for free from approximation errors. Theoretical TCA for any cell on synthetic surfaces is analytically solved by using subsection integral and L'Hospital’s rule based on the topographical definition of TCA. The impacts of grid discretization on the spatial patterns of theoretical TCA are explained mathematically and geometrically. In case studies, the analytically solved theoretical TCA is treated as a benchmark to quantitatively evaluate the TCAs estimated by three SFD algorithms (i.e., D8, Rho8, and D8‐LTD) and three MFD algorithms (i.e., FDFM, MFD‐md, and D∞). Results show that (1) SFD algorithms obtain unsmooth and discontinuous spatial patterns of estimated TCA, due to the existence of source cells caused by the basic hypothesis of allowing only one receiving cell; (2) Cross compensation induced by artificial dispersion in MFD algorithms leads to a less error in the quantity of estimated TCA but a larger error in the physical position of estimated TCA; (3) The addition of contour length errors does not promise larger specific contributing area errors than TCA errors. To summarize, this work offers a theoretical and quantitative evaluation on the precision of the TCAs estimated by flow direction algorithms.
Improving the Representation of Long‐Term Storage Variations With Conceptual Hydrological Models in Data‐Scarce Regions
Authors: Hulsman Petra , Hrachowitz Markus , Savenije Hubert H. G.
Published: March 2021

In the Luangwa basin in Zambia, long‐term total water storage variations were observed with Gravity Recovery and Climate Experiment, but not reproduced by a standard conceptual hydrological model that encapsulates our current understanding of the dominant regional hydrological processes. The objective of this study was to identify potential processes underlying these low‐frequency variations through combined data analysis and model hypothesis testing. First, we analyzed the effect of data uncertainty by contrasting observed storage variations with multi‐annual estimates of precipitation and evaporation from multiple data sources. Second, we analyzed four different combinations of model forcing and evaluated their skill to reproduce the observed long‐term storage variations. Third, we formulated alternative model hypotheses for groundwater export to potentially explain low‐frequency storage variations. Overall, the results suggest that the initial model's inability to reproduce the observed low‐frequency storage variations was partly due to the forcing data used and partly due to the missing representation of regional groundwater export. More specifically, the choice of data source affected the model's ability to reproduce annual maximum storage fluctuations, whereas the annual minima improved by adapting the model structure to allow for groundwater export from a deeper groundwater layer. This suggests that, in contrast to previous research, conceptual models can reproduce long‐term storage fluctuations if a suitable model structure is used. Overall, the results highlight the value of alternative data sources and iterative testing of model structural hypotheses to improve runoff predictions in a poorly gauged basin leading to enhanced understanding of its hydrological processes.
Single Particle Multipole Expansions From Micromagnetic Tomography
Authors: Cortés‐Ortuño David , Fabian Karl , de Groot Lennart V.
Published: March 2021

Micromagnetic tomography aims at reconstructing large numbers of individual magnetizations of magnetic particles from combining high‐resolution magnetic scanning techniques with micro X‐ray computed tomography (microCT). Previous work demonstrated that dipole moments can be robustly inferred, and mathematical analysis showed that the potential field of each particle is uniquely determined. Here, we describe a mathematical procedure to recover higher orders of the magnetic potential of the individual magnetic particles in terms of their spherical harmonic expansions (SHE). We test this approach on data from scanning superconducting quantum interference device microscopy and microCT of a reference sample. For particles with high signal‐to‐noise ratio of the magnetic scan we demonstrate that SHE up to order n = 3 can be robustly recovered. This additional level of detail restricts the possible internal magnetization structures of the particles and provides valuable rock magnetic information with respect to their stability and reliability as paleomagnetic remanence carriers. Micromagnetic tomography therefore enables a new approach for detailed rock magnetic studies on large ensembles of individual particles.
Effects of Using High Resolution Satellite‐Based Inundation Time Series to Estimate Methane Fluxes From Forested Wetlands
Authors: Hondula Kelly L. , DeVries Ben , Jones C. Nathan , Palmer Margaret A.
Published: March 2021

A major source of uncertainty in the global methane budget arises from quantifying the area of wetlands and other inland waters. This study addresses how the dynamics of surface water extent in forested wetlands affect the calculation of methane emissions. We used fine resolution satellite imagery acquired at sub‐weekly intervals together with a semiempirical methane emissions model to estimate daily surface water extent and diffusive methane fluxes for a low‐relief wetland‐rich watershed. Comparisons of surface water model predictions to field measurements showed agreement with the magnitude of changes in water extent, including for wetlands with surface area less than 1,000 m2. Results of methane emission models showed that wetlands smaller than 1 hectare (10,000 m2) were responsible for a majority of emissions, and that considering dynamic inundation of forested wetlands resulted in 49%–62% lower emission totals compared to models using a single estimate for each wetland’s size.
Does Dynamic Downscaling Modify the Projected Impacts of Stabilized 1.5°C and 2°C Warming on Hot Extremes Over China?
Authors: Ge Jun , Qiu Bo , Wu Runqi , Cao Yipeng , Zhou Weidan , Guo Weidong , Tang Jianping
Published: March 2021

Using Weather Research and Forecasting (WRF) model, we perform the first dynamic downscaling of Community Earth System Model (CESM) Low‐Warming simulations to examine hot extreme changes over China in response to stabilized 1.5°C and 2°C global warming. WRF projects more intense and frequent hot extremes due to global warming, which are qualitatively consistent with CESM. However, WRF and CESM significantly differ in magnitudes of hot extreme changes. Compared to CESM, WRF indicates larger increases in hot extremes over Tibetan Plateau but smaller increases over other regions. Such differences between WRF and CESM are mainly caused by divergent projections of shortwave radiation changes. WRF also suggests fewer benefits achieved from the additional 0.5°C warming constraint than CESM. This study demonstrates the climate risks might be inadequately informed by global climate models and it is necessary to reevaluate impacts of 1.5°C and 2°C global warming on regional climate based on regional climate models.