bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining 3D seismics, eyewitness accounts and numerical simulations to reconstruct the 1888 Ritter Island sector collapse and tsunami
Authors: Karstens Jens , Kelfoun Karim , Watt Sebastian F. L. , Berndt Christian
Published: April 2020

The 1888 Ritter Island volcanic sector collapse triggered a regionally damaging tsunami. Historic eyewitness accounts allow the reconstruction of the arrival time, phase and height of the tsunami wave at multiple locations around the coast of New Guinea and New Britain. 3D seismic interpretations and sedimentological analyses indicate that the catastrophic collapse of Ritter Island was preceded by a phase of deep-seated gradual spreading within the volcanic edifice and accompanied by a submarine explosive eruption, as the volcanic conduit was cut beneath sea level. However, the potential impact of the deep-seated deformation and the explosive eruption on tsunami genesis is unclear. For the first time, it is possible to parameterise the different components of the Ritter Island collapse with 3D seismic data, and thereby test their relative contributions to the tsunami. The modelled tsunami arrival times and heights are in good agreement with the historic eyewitness accounts. Our simulations reveal that the tsunami was primarily controlled by the displacement of the water column by the collapsing cone at the subaerial-submarine boundary and that the submerged fraction of the slide mass and its mobility had only a minor effect on tsunami genesis. This indicates that the total slide volume, when incorporating the deep-seated deforming mass, is not directly scalable for the resulting tsunami height. Furthermore, the simulations show that the tsunamigenic impact of the explosive eruption energy during the Ritter Island collapse was only minor. However, this relationship may be different for other volcanogenic tsunami events with smaller slide volumes or larger magnitude eruptions, and should not be neglected in tsunami simulations and hazard assessment.
Urban storage heat flux variability explored using satellite, meteorological and geodata
Authors: Lindberg F. , Olofson K. F. G. , Sun T. , Grimmond C. S. B. , Feigenwinter C.
Published: April 2020

The storage heat flux (ΔQS) is the net flow of heat stored within a volume that may include the air, trees, buildings and ground. Given the difficulty of measurement of this important and large flux in urban areas, we explore the use of Earth Observation (EO) data. EO surface temperatures are used with ground-based meteorological forcing, urban morphology, land cover and land use information to estimate spatial variations of ΔQSin urban areas using the Element Surface Temperature Method (ESTM). First, we evaluate ESTM for four “simpler” surfaces. These have good agreement with observed values. ESTM coupled to SUEWS (an urban land surface model) is applied to three European cities (Basel, Heraklion, London), allowing EO data to enhance the exploration of the spatial variability in ΔQS. The impervious surfaces (paved and buildings) contribute most to ΔQS. Building wall area seems to explain variation of ΔQSmost consistently. As the paved fraction increases up to 0.4, there is a clear increase in ΔQS. With a larger paved fraction, the fraction of buildings and wall area is lower which reduces the high values of ΔQS.
Enhancing the substrate tolerance of DszC by a combination of alanine scanning and site-directed saturation mutagenesis
Authors: Li Lu , Ye Lei , Lin Ying , Zhang Wei , Liao Xihao , Liang Shuli
Published: April 2020

The biodesulfurization 4S pathway can specifically desulfurize an aromatic S heterocyclic compound (which is difficult to desulfurize by hydrodesulfurization) and maintain the integrity of its combustion value. The four Dsz enzymes in the pathway convert the model compound dibenzothiophene (DBT) into the sulfur-free compound 2-hydroxybiphenyl (HBP). DszC is the first enzyme in the 4S pathway and is subject to feedback inhibition and substrate inhibition. This study is the first attempt to further modify the DszC mutant AKWC to improve its tolerance to DBT. Alanine scanning was performed on the dimeric surface of the DszC mutant AKWC, and the HBP yield of the BAD (AKWCP413A) strain was increased compared to the BAD (AKWC) strain. Site-directed saturation mutagenesis was performed on the 413th amino acid of AKWC, and the substrate inhibition parameter KI value of the mutant AKWCPI was 5.6 times higher than that of AKWC. When the DBT concentration was 0.25 mM, the HBP production of the recombinant strain overexpressing AKWCPI was increased by approximately 1.4-fold compared to the BL21(DE3)/BADC*+C* strain. The protein engineering of DszC further improved the substrate tolerance after overcoming the feedback inhibition, which provided a reference for the analysis of the inhibition mechanism of DszC substrate. Overexpression of DszC-beneficial mutants also greatly improved the efficiency of desulfurization.
A note on deterministic updating and van Fraassen’s symmetry argument for conditionalization
Authors: Pettigrew Richard
Published: April 2020

In a recent paper, Pettigrew (Philos Stud, 2019. https://doi.org/10.1007/s11098-019-01377-y) argues that the pragmatic and epistemic arguments for Bayesian updating are based on an unwarranted assumption, which he calls deterministic updating, and which says that your updating plan should be deterministic.
In that paper, Pettigrew did not consider whether the symmetry arguments due to Hughes and van Fraassen make the same assumption (Hughes and van Fraassen in: Proceedings of the Biennial Meeting of the Philosophy of Science Association. pp. 851–869, 1984; van Fraassen in: Rescher N (ed) Scientific inquiry in philosophical perspective. University Press of America, Lanham, pp. 183–223, 1987). In this note, I show that they do.
Why do females choose to study humanities or social sciences, while males prefer technology or science? Some intrapersonal and interpersonal predictors
Authors: Trusz Sławomir
Published: April 2020

The article attempts to answer the question why females prefer humanities/social studies, whereas males opt for technology/science. For this purpose, the study majors selected by 445 females and 431 males were linked by logit functions with: (1) parents’ and (2) teachers’ expectancies, (3) students’ self-expectancies, (4) their self-concepts of abilities and (5) time spent on learning mathematics and (6) literacy, (7) test results in mathematics and (8) literacy, (9) gender of mathematics, and (10) literacy teacher in the 12th grade. Interaction effects of the mathematics and literacy teacher’s gender with the abovementioned predictors were also quantified. Females’ selections were mostly influenced by teachers’ expectancies, while for males, by their self-concepts. The teacher’s gender modified tested relations in five (females) and nine (males) cases. The results were discussed on the grounds of the theory of intra- and interpersonal expectancies as learning regulators.
Hydrodynamic modelling of traffic-related microplastics discharged with stormwater into the Göta River in Sweden
Authors: Bondelind Mia , Sokolova Ekaterina , Nguyen Ailinh , Karlsson Dick , Karlsson Anna , Björklund Karin
Published: April 2020

Microplastics (MP) are transported from land-based sources from rivers to marine waters. However, there is currently little knowledge about MP fate from land sources to marine waters. Traffic is estimated to be one of the largest sources of MP; hence, stormwater is expected to be an important transportation route of MP to marine waters. The aim of this study was to investigate the effect of the size and density of tyre wear particles in road run-off on their fate in the Göta River in Sweden using hydrodynamic modelling. The model of the stretch of Göta River, Sweden’s largest river, passing through Gothenburg (Sweden’s second largest city) and out to the sea, was set up using MIKE 3 FM software. Literature data were used to define the MP characteristics: concentrations in stormwater, prevalent particle sizes, density of MP commonly occurring in road run-off and settling velocities. Results show that higher concentrations of MP are found on the south side of the river, compared with the north side, due to higher annual average daily traffic loads along the south side of the river. The mixing processes in the river and the MP concentrations were generally influenced by the vertical water density gradient caused by saline water from the Kattegat strait. While most MP with higher density and larger size settle in the river, smaller MP with density close to 1.0 g/cm3 do not settle in the river and therefore reach the Kattegat strait and the marine environments. Further research is needed to describe the fate and transport of microplastics in the stormwater system, including treatment facilities, i.e. biofouling, aggregation, degradation and/or further fragmentation and settling.
Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique
Authors: Vogel Christian , Hoffmann Marie C. , Krüger Oliver , Murzin Vadim , Caliebe Wolfgang , Adam Christian
Published: April 2020

Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and for most tested materials selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) so that Cr(VI) values are overestimated. Since certain types of the P-fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr).
Phytotoxicity and phytogenotoxicity of soil and air in the vicinity of a petrochemical plant in Płock (Poland)
Authors: Karaczun Zbigniew M. , Obidoska Grażyna , Żarska Barbara
Published: April 2020

Petrochemical industries have been widely recognised as important emission sources of airborne contaminants including heavy metals and polycyclic aromatic hydrocarbons PAHs, which affect the quality of air, soil and vegetation. In this study, our aim was to examine the phytotoxicity and phytogenotoxicity of soils and air in the vicinity of a petrochemical plant, in order to assess the potential threat of such industrial objects for crops and natural vegetation, in the cases when the allowable concentrations of contaminants are not exceeded and the plants in the vicinity visually do not seem to be affected. For phytotoxicity and phytogenotoxicity assessment, the Phytotoxkit and respectively Vicia RTA and TRAD MCN bioassays were used. According to our results, in spite of relatively low content of heavy metals and PAHs (hardly any exceedance of standards), the phytotoxicity and especially phytogenotoxicity of soil samples collected up to 18 km from the refinery were detected by the bioindicators. The phytogenotoxicity of air was also indicated within the distance of up to 12 km. We concluded that to obtain the complete view of the environmental risks in a surveyed area, a combination of chemical analysis of environmental samples with the bioindication methods should be implemented. In addition, setting the acceptable levels of contaminants should involve a more extensive use of bioindication methods (especially genotoxicity assessment).
Relationships Between Vitamin D Status and PTH over 5 Years After Roux-en-Y Gastric Bypass: a Longitudinal Cohort Study
Authors: Hewitt Stephen , Kristinsson Jon , Aasheim Erlend Tuseth , Blom-Høgestøl Ingvild Kristine , Aaseth Eirik , Jahnsen Jørgen , Eriksen Erik Fink , Mala Tom
Published: April 2020

Purpose

Secondary hyperparathyroidism (SHPT) after obesity surgery may affect bone health. Optimal vitamin D levels have not been established to prevent SHPT postoperatively. We investigated whether SHPT differed across threshold levels of serum 25-hydroxyvitamin D (S-25(OH)D) from 6 months up to 5 years after Roux-en-Y gastric bypass (RYGB).

Materials and Methods

We included 554 patients at follow-up 5 years postoperatively. Blood samples were analysed for S-25(OH)D, ionized calcium (iCa) and parathyroid hormone (PTH) during follow-up.

Results

PTH and prevalence of SHPT increased from 6 months to 5 years postoperatively, while S-25(OH)D and iCa decreased (all P < 0.001). PTH and SHPT development are related with S-25(OH)D, and PTH differed between all subgroups of S-25(OH)D. SHPT occurred less frequently across all subgroups of S-25(OH)D ≥ 50 nmol/l during follow-up: odds ratio (OR) 0.44 (95% CI 0.36–0.54) in patients with S-25(OH)D ≥ 50 nmol/l, OR 0.38 (0.30–0.49) with S-25(OH)D ≥ 75 nmol/l and OR 0.19 (0.12–0.31) with S-25(OH) D ≥ 100 nmol/l, all compared with S-25(OH)D < 50 nmol/l. At 5 years, 208/554 patients (38%) had SHPT; SHPT was found in 94/188 patients (50%) with S-25(OH)D < 50 nmol/l, in 69/222 (31%) with S-25(OH)D 50–74 nmol/l, in 40/117 (34%) with S-25(OH)D 75–99 nmol/l and in 5/27 (19%) with S-25(OH)D ≥ 100 nmol/l. An interaction existed between S-25(OH)D and iCa. Bone alkaline phosphatase remained increased with SHPT.

Conclusions

A significant relationship existed between S-25(OH)D and development of PTH and SHPT. The prevalence of SHPT was lower with threshold levels 25(OH)D ≥ 50 nmol/l and ≥ 75 nmol/l over the 5 years, and lowest with S-25(OH)D ≥ 100 nmol/l.
FEMfuns: A Volume Conduction Modeling Pipeline that Includes Resistive, Capacitive or Dispersive Tissue and Electrodes
Authors: Vermaas M. , Piastra M. C. , Oostendorp T. F. , Ramsey N. F. , Tiesinga P. H. E.
Published: April 2020

Applications such as brain computer interfaces require recordings of relevant neuronal population activity with high precision, for example, with electrocorticography (ECoG) grids. In order to achieve this, both the placement of the electrode grid on the cortex and the electrode properties, such as the electrode size and material, need to be optimized. For this purpose, it is essential to have a reliable tool that is able to simulate the extracellular potential, i.e., to solve the so-called ECoG forward problem, and to incorporate the properties of the electrodes explicitly in the model. In this study, this need is addressed by introducing the first open-source pipeline, FEMfuns (finite element method for useful neuroscience simulations), that allows neuroscientists to solve the forward problem in a variety of different geometrical domains, including different types of source models and electrode properties, such as resistive and capacitive materials. FEMfuns is based on the finite element method (FEM) implemented in FEniCS and includes the geometry tessellation, several electrode-electrolyte implementations and adaptive refinement options. The code of the pipeline is available under the GNU General Public License version 3 athttps://github.com/meronvermaas/FEMfuns. We tested our pipeline with several geometries and source configurations such as a dipolar source in a multi-layer sphere model and a five-compartment realistically-shaped head model. Furthermore, we describe the main scripts in the pipeline, illustrating its flexible and versatile use. Provided with a sufficiently fine tessellation, the numerical solution of the forward problem approximates the analytical solution. Furthermore, we show dispersive material and interface effects in line with previous literature. Our results indicate substantial capacitive and dispersive effects due to the electrode-electrolyte interface when using stimulating electrodes. The results demonstrate that the pipeline presented in this paper is an accurate and flexible tool to simulate signals generated on electrode grids by the spatiotemporal electrical activity patterns produced by sources and thereby allows the user to optimize grids for brain computer interfaces including exploration of alternative electrode materials/properties.
Preliminary aerodynamic design of a reusable booster flight experiment
Authors: Merrem C. , Wartemann V. , Eggers Th.
Published: April 2020

The Reusable Flight Experiment (ReFEx) is an experimental vehicle currently in development by the German Aerospace Center (DLR), which simulates the reentry of a winged reusable booster stage. The topic covered in this paper is the aerodynamic design through the Mach number range from 5.0 to 0.8, including the transonic regime, by CFD simulations using the DLR TAU-Code. For steering and lift generation, the vehicle is equipped with multiple aerodynamic surfaces: canards, wings and a vertical fin. A VSB30 was chosen as the carrier rocket, leading to numerous limiting conditions that had to be fulfilled. The resulting tradeoffs are discussed. Also the process to achieve a configuration that meets all needs regarding stability during ascent and descent, controllability and energy management to autonomously follow a desired trajectory is explained. Since this vehicle is under development, the presented geometry is not necessarily the final shape. However, the completed design iterations strongly indicate that only details will differ between the presented state to the final and flyable ReFEx, scheduled to fly in 2022.
Effect of extrusion on the polymerization of wheat glutenin and changes in the gluten network
Authors: Jia Feng , Wang Jinshui , Wang Qi , Zhang Xia , Di Chen  , Chen Yu , Zhang Changfu
Published: April 2020

The changes in the gluten network during extrusion treatment were studied by assessing the polymerization behavior of glutenin. Gluten samples were extruded at different barrel temperatures, screw speeds, and flow rates. The results indicated that high molecular weight glutenin subunits increased while free sulfhydryl groups and low molecular weight glutenin subunits decreased as the screw speeds and flow rates increased during extrusion treatment. Specific β-sheet structures of gluten clearly increased, while α-helices and β-turns fluctuated during extrusion processing, thus forming a tight gluten network. The characteristics of the protein network were evaluated by confocal laser scanning microscopy. The results showed that a homogeneous and denser gluten network was formed at higher extrusion temperatures during the extrusion process, which may be related to the polymerization of low-molecular-weight glutenin subunits. This study provides a theoretical basis for the improvement and regulation of extrusion quality during the gluten extrusion process.
Diagenetic impacts on hydraulic flow unit properties: insight from the Jurassic carbonate Upper Arab Formation in the Persian Gulf
Authors: Sharifi-Yazdi Masoud , Rahimpour-Bonab Hossain , Nazemi Maziyar , Tavakoli Vahid , Gharechelou Sajjad
Published: April 2020

The Upper Arab reservoir in the central Persian Gulf was examined for depositional, diagenetic, sequence stratigraphic and petrophysical features. This succession is composed of eight sedimentary facies that deposited on a carbonate ramp. Three-third-order sequences prograded across the Late Jurassic Arab Platform. This interval was complicated by multiple diagenetic phases including eogenesis and mesogenesis that strongly influenced reservoir properties. Dolomitization, dissolution, cementation and compaction are major diagenetic processes which played an essential role in increasing or decreasing reservoir quality. Four hydraulic flow units (HFU) were determined by flow zone indicator approach for evaluation of the reservoir quality. In addition to depositional features, diagenetic alterations have changed general HFUs characterizations such as porosity, permeability and pore-throat size. Likewise, via Lucia classification, HFUs of the Arab reservoir were grouped based on the integration of geological and petrophysical attributes in detail. Among diagenetic processes, dolomitization and dissolution have positive effects while cementation and stylolitization have a negative effect on HFUs characteristics in the studied reservoir. Put another way, since diagenetic alterations lead to the intensification of heterogeneity in carbonate reservoir, prediction of the relationship between pore type and pore throat size is a problematic issue. Recognition of the hydraulic flow units considered as a practical tool for grouping reservoir rocks and characterizing heterogeneity using porosity and permeability relationship. Finally, specifying of the contribution of various diagenetic imprints in each hydraulic flow unit in a sequence stratigraphic framework results in a conceptual reservoir model that could predict reservoir quality variations across the field.
Investigation of adsorption mechanism of phosphate(V) ions on the nanostructured Na-A zeolite surface modified with ionic polyacrylamide with regard to their removal from aqueous solution
Authors: Wiśniewska Małgorzata , Urban Teresa , Chibowski Stanisław , Fijałkowska Gracja , Medykowska Magdalena , Nosal-Wiercińska Agnieszka , Franus Wojciech , Panek Rafał , Szewczuk-Karpisz Katarzyna
Published: April 2020

The sorption properties of Na-A-type synthetic zeolite, obtained from fly ash with regard to the phosphate(V) ions, were determined. The Na-A zeolite was prepared using hydrothermal conversion of fly ash with aqueous sodium hydroxide. The effects of solution pH and zeolite surface modification by ionic polyacrylamide (PAM) were examined. Both anionic and cationic forms of PAM were applied. The adsorption and electrokinetic data were obtained by means of spectrophotometric measurements, potentiometric titrations and zeta potential determination. It was shown that the presence of ionic polyacrylamide adsorption layers modifies the surface properties of the solid. The resulting composite material (zeolite/polymer) can be applied for effective removal of phosphate(V) ions from the liquid medium. Its regeneration possibilities are also considerable. Additionally, the use of fly ash for zeolite preparation leads to management of hazardous waste material.
Skull base chordomas review of current treatment paradigms
Authors: Yaniv Dan , Soudry Ethan , Strenov Yulia , Cohen Marc A. , Mizrachi Aviram
Published: April 2020

Background

Chordomas are locally invasive neoplasms, arising from notochordal remnants and can appear anywhere along the axial skeleton. Local recurrences are common, and distant metastases may occur years after the initial presentation.

Methods

Literature review of current treatment strategies for chordomas of the skull base.

Results

Surgery is the mainstay of treatment and complete resection has paramount importance for prognosis.

When complete resection is not achieved recurrent disease is common. The anatomical complexity of the skull base makes resection complex. Endonasal endoscopic approaches to the clivus has become increasingly favored in recent years although addressing reconstruction of the skull base to prevent CSF leak may be challenging.

Evidence suggests that radiotherapy should not be considered as a primary single modality when trying to achieve cure of the disease. Nonetheless, immediate post‐operative radiotherapy improves survival. Many strategies have been suggested to preserve sensitive vital structures in the skull base during treatment but as for survival there is no evidence of advantage when comparing adjuvant therapy with photon radiotherapy, gamma knife surgery, proton beam therapy, and carbon ion radiation therapy.

There is no evidence to support cytotoxic chemotherapy in the treatment of chordomas but targeted therapies have started to show promise. Several optional molecular targets exist. Brachyury is overexpressed in 95% of chordomas but not in other mesenchymal neoplasms. However, its precise role in chordoma pathogenesis is currently unclear, and its cellular location in the nucleus makes it difficult to target. The inhibition of brachyury in chordoma cell lines induces growth arrest and apoptosis. This does not have clinical application to date. There are retrospective results with different molecular targeted therapies for advanced chordomas with some effectiveness.

Conclusion

Despite improvements made in the past 10 years in our knowledge of chordoma biology, available therapies still offer a limited benefit. There is an unmet need for new therapeutic options for patients with advanced disease. Therefore, patients with advanced disease should be encouraged to participate in clinical trials when and where available.
Observed and CMIP5‐Simulated Radiative Flux Variability Over West Africa
Authors: Mackie Anna , Wild Martin , Brindley Helen , Folini Doris , Palmer Paul I.
Published: April 2020

We explore the ability of general circulation models in the Coupled Model Intercomparison Project (CMIP5) to recreate observed seasonal variability in top‐of‐the‐atmosphere and surface radiation fluxes over West Africa. This tests CMIP5 models' ability to describe the radiative energy partitioning, which is fundamental to our understanding of the current climate and its future changes. We use 15 years of the monthly Clouds and the Earth's Radiant Energy System Energy Balanced and Filled (EBAF) product, alongside other satellite, reanalysis, and surface station products. We find that the CMIP5 multimodel mean is generally within the reference product range, with annual mean CMIP5 multimodel mean—EBAF of −0.5 W m−2 for top‐of‐the‐atmosphere reflected shortwave radiation, and 4.6 W m−2 in outgoing longwave radiation over West Africa. However, the range in annual mean of the model seasonal cycles is large (37.2 and 34.0 W m−2 for reflected shortwave radiation and outgoing longwave radiation, respectively). We use seasonal and regional contrasts in all‐sky fluxes to infer that the representation of the West African monsoon in numerical models affects radiative energy partitioning. Using clear‐sky surface fluxes, we find that the models tend to have more downwelling shortwave and less downwelling longwave radiation than EBAF, consistent with past research. We find models that are drier and have lower aerosol loading tend to show the largest differences. We find evidence that aerosol variability has a larger effect in modulating downwelling shortwave radiation than water vapor in EBAF, while the opposite effect is seen in the majority of CMIP5 models.
Large‐Scale Dynamics and Moisture Sources of the Precipitation Over the Western Tibetan Plateau in Boreal Winter
Authors: Liu Xiaolin , Liu Yimin , Wang Xiaocong , Wu Guoxiong
Published: April 2020

One of the heaviest precipitations over the Asian continent in winter is located in the western Tibetan Plateau (TP). In this study, the dynamics of the precipitation over the western TP (PWTP) in boreal winter and its interannual variability are explored. The moisture origins and paths are detected using a Lagrangian Integrated Trajectory model. In climatology, the PWTP is generated as results of upward air motions on the windward side of the TP and ranges from 0.5 to 2.5 mm·day−1. Under the influence of midlatitude westerlies and the subtropical high over the Arabian Peninsula, three key moisture sources (by percentage contribution) are identified: South Asia‐North Indian Ocean (56.6%), Central Eurasia‐North Africa (37.7%), and Central‐North Atlantic (5.6%). The dominant precipitating cloud types are nimbostratus and stratus/stratocumulus derived from satellite data. On the interannual timescale, PWTP variation is closely associated with El Niño‐Southern Oscillation (ENSO) and midlatitude cyclones. ENSO warm events lead to an anomalous anticyclone over the tropical northwest Indian Ocean and intensify moisture transport northward in the lower troposphere, as well as abnormal divergence in upper troposphere. However, ENSO explains only about 38.1% of the PWTP variance. Midlatitude teleconnection also contributes to the PWTP variability, which is comparable to the effect of ENSO. The cyclones imbedded in the subtropical jet are part of the teleconnection, with an anticyclone upstream over the North Atlantic and an cyclone over the western TP. Further evidence suggests that the transient eddies in the North Atlantic help to maintain the teleconnection.
Tuning in to a Glacial Symphony
Authors: Evans Ogden Lesley
Published: April 2020

New research focuses on the bubbling and bathtub-like sounds of a glacier.
This Week: Fake News, Floods, and a Dazzling Flyby
Authors:   AGU
Published: April 2020

What Earth and space science stories are we recommending this week?
The Role of Vertically and Obliquely Propagating Gravity Waves in Influencing the Polar Summer Mesosphere
Authors: Thurairajah Brentha , Cullens Chihoko Yamashita , Siskind David E. , Hervig Mark E. , Bailey Scott M.
Published: April 2020

Using an 8‐year (2007–2014) data set from two different limb‐viewing instruments, we evaluate the relative roles of vertically versus obliquely propagating gravity waves (GWs) as sources of GWs in the polar summer mesosphere. Obliquely propagating waves are of interest because they are presumed to be generated by the summer monsoons. In the high‐latitude upper mesosphere, the correlation coefficient between the time series of ice water content (IWC) and GW amplitude is 0.48, indicating that the observed GWs enhance polar mesospheric clouds (PMCs). For vertically propagating waves, the correlation coefficient between IWC and stratospheric/lower mesospheric (20–70 km) GW amplitude at the same high latitudes becomes more negative with increasing altitude. This change in correlation from negative in the lower mesosphere to positive at PMC altitudes suggests the presence of another source of GWs. The positive correlation coefficient between the time series of IWC and GW amplitude from 0–50°N, 20–90 km shows a slanted structure suggesting oblique propagation. This slanted structure is more robust in some seasons compared to others, and this interannual variability may be due to the latitudinal gradient of the mesospheric easterly jet where steeper gradients allow for low‐latitude tropospheric GWs to be refracted to the high‐latitude mesosphere more efficiently. Gravity‐Wave Regional or Global Ray Tracer (GROGRAT) ray tracing simulations show that more GWs propagate obliquely compared to vertically propagating waves that reach PMC altitudes. For obliquely propagating waves, GROGRAT simulations indicate that nonorographic tropospheric GWs with faster phase speed (>20 m/s) and longer horizontal wavelength (>400 km) have a higher probability of reaching the polar summer mesosphere.
Resistance Formulations in Shallow Overland Flow Along a Hillslope Covered With Patchy Vegetation
Authors: Crompton Octavia , Katul Gabriel G. , Thompson Sally
Published: April 2020

Describing the effects of surface roughness on flow resistance remains a first‐order challenge for modeling shallow overland flow using the Saint Venant equations (SVE). This challenge has resulted in a proliferation of roughness schemes relating the properties of a uniform rough surface to bulk velocity and resistance, making selection of an appropriate roughness scheme daunting—especially on heterogeneous surfaces. For hydrological predictions, a roughness scheme is appropriate if the resulting SVE solutions predict outcomes such as water balance partitioning between runoff and infiltration, the hillslope hydrograph, and the discharge velocity with uncertainties that are less than or comparable to uncertainty in measurements. To assess the sensitivity of hydrological predictions to the choice of a roughness scheme, multiple schemes are first calibrated to each other under equilibrium flow conditions while imposing the kinematic wave approximation at the outlet. This approach yields analytical relations between the parameters of different roughness schemes when applied to the same hillslope and discharge. The approach is used to provide a parameterization of five commonly used roughness schemes for a common surface, and the predictions of the schemes for multiple patchily vegetated hillslopes are compared. The results suggest that, once calibrated, there is minimal prediction sensitivity to the choice of roughness scheme across a wide range of rainfall conditions. Operationally, the results demonstrate that parameterizing a roughness schemes is of higher significance for predicting hydrological patterns than the precise formulation employed.
Shenling Baizhu San improves functional dyspepsia in rats as revealed by 1H-NMR based metabolomics
Authors: Zhang Shaobao , Xu Zengmei , Cao Xueqing , Xie Yuzhen , Lin Lei , Zhang Xiao , Zou Baorong , Liu Deliang , Cai Ying , Liao Qiongfeng , Xie Zhiyong
Published: April 2020

Functional dyspepsia (FD), a common gastrointestinal disorder around the world, is driven by multiple factors, making prevention and treatment a major challenge.
Organostannane-free polycondensation and eco-friendly processing strategy for the design of semiconducting polymers in transistors
Authors: Ran Yang , Guo Yunlong , Liu Yunqi
Published: April 2020

We introduce green synthetic methods and environmentally benign processing strategies that provide some ideas for total green fabrication of electronic devices.
Accurately controlling the hierarchical nanostructure of polyamide membranesviaelectrostatic atomization-assisted interfacial polymerization
Authors: Chen Jingjing , Zhang Jie , Wu Xiaoli , Cui Xulin , Li Wenpeng , Zhang Haoqin , Wang Jingtao , Cao Xing-Zhong , Zhang Peng
Published: April 2020

Polyamide membranes with an accurately controlled hierarchical nanostructure permit ultrafast solvent permeation and efficient solute rejection.
Injectable oxygen-generating nanocomposite hydrogels with prolonged oxygen delivery for enhanced cell proliferation under hypoxic and normoxic conditions
Authors: Motealleh Andisheh , Kehr Nermin S.
Published: April 2020

We describe a new organic peroxide-based injectable biomaterial that provides sustained O2 within the 3D biomaterial scaffold and so enhances the viability of healthy fibroblast cells, while reduces the proliferation of malignant cells.
Electrides: a review
Authors: Liu Chang , Nikolaev Sergey A. , Ren Wei , Burton Lee A.
Published: April 2020

Electrides are systems in which an electron is not bound to an atom and plays an active role in the structure. The three types of electron confinement have been confirmed.
Moderately compressed high‐swing class‐C/B VCO with accurate current control
Authors: Zhang G.
Published: April 2020

A high‐swing class‐C/B VCO without tail current source has been proposed. Accurate current control and dynamic bias generation that are essential to robust start‐up and class‐C operation are achieved through mirroring VCO LDO current and comparing against bias current. The VCO oscillation amplitude is designed to be sufficiently large and the core transistors are compressed moderately, such that the oscillation amplitude is stable while the VCO operates in class‐C mode. A prototype PMOS VCO in a 0.13 μm process demonstrated a measured VCO figure of merit of 192 dB at 4.7 GHz with 1.4 mA current and core VDD at 0.6 V.
Mm‐wave single‐pole single‐throw m‐HEMT switch with low loss and high linearity
Authors: Kim Younghwan , Jeon Sanggeun
Published: April 2020

This Letter presents a single‐pole single‐throw (SPST) switch for high‐power applications in the mm‐wave frequency band. A stacked‐FET structure is adopted in the shunt switching cell for reducing the insertion loss and improving the linearity of the switch. To enhance the isolation, the parasitic inductance of the stacked‐FET structure is resonated out by connecting a series capacitor. The number of stacked FETs in each shunt cell and the number of the shunt cells are optimised considering the trade‐off among the insertion loss, isolation, and linearity. The SPST switch is fabricated in a 70‐nm GaAs m‐HEMT process. The measurement shows that the insertion loss is <1.1 dB, and the isolation is >25 dB over the frequency from 59 to 77 GHz. Both the insertion loss and isolation are not compressed at all until the input power reaches 19.5 dBm at 75 GHz.
Availability modelling of terrestrial hybrid FSO/RF based on weather statistics from tropical region
Authors: Basahel Ahmed A. , Rafiqul Islam Md. , Habaebi Mohamed Hadi , Zabidi Suriza A.
Published: April 2020

Free‐space optical (FSO) communication links are point‐to‐point wireless technologies. It provides high data rates up to a gigabit per second. FSO link availability is easily affected by different weather conditions. Radio‐frequency (RF) can be a complimentary link to the FSO link to increase availability. Hybrid FSO/RF is a feasible technology for providing high availability of point‐to‐point wireless links. In tropical regions, normally RF link is relatively sensitive to rain. Availability prediction of hybrid FSO/RF with the selection of suitable RF is indispensable, especially in tropical regions. In this study, empirical models are proposed to predict the link availability of RF, and hybrid FSO/RF over link ranges up to 5 km. The availability prediction models are based on the long‐term statistics of atmospheric attenuations from the tropical climate zone. The RF link availability prediction model is developed for frequency ranges from 10 to 100 GHz using the International Telecommunications Union‐Radio (ITU‐R) rain attenuation model. It is link distance, fade margin, and radio frequency dependent. The proposed availability models can predict carrier as well as enterprise class availability. The availabilities predicted by proposed models are found to be in good agreement with those estimated by the ITU‐R.
Slot‐hitting ratio‐based TDMA schedule for hybrid energy‐harvesting wireless sensor networks
Authors: Gong Siliang , Liu Xiaoying , Zheng Kechen , Tian Xianzhong , Zhu Yi‐hua
Published: April 2020

In the energy‐harvesting wireless sensor networks (EH‐WSNs) with Time division multiple access (TDMA), it is challenging to assign time slots to the nodes because energy shortage causes some nodes unable to transmit in their time slots, resulting in the inefficiency in slot usage and the increase of the data packet delay. To overcome this problem, the slot assignment in TDMA is required to consider energy packet arrivals, where an energy packet is defined as the amount of energy that suffices for one transmission. In this study, the authors investigate the EH‐WSN with hybrid energy sources, in which the nodes harvest energy from the fixed inter‐arrival time (FIAT) and the random inter‐arrival time (RIAT) energy sources. After deriving the slot‐hitting ratios (SHRs) of energy packet arrivals for both FIAT and RIAT energy sources, they propose the SHR‐based TDMA (SHR‐TDMA) scheme. Then, they derive the delay arising from the awaiting slot (DAFAS) and formulate the DAFAS minimisation problem for the SHR‐TDMA. Solution to the DAFAS minimisation problem makes the slots optimally assigned according to the characteristics of the energy packet arrivals at the nodes. The simulation results show that the SHR‐TDMA outperforms the existing TDMA schemes in terms of DAFAS.
Efficient localisation approach for WSNs using hybrid DA–FA algorithm
Authors: Singh Prabhjot , Mittal Nitin
Published: April 2020

Localisation has become a major attraction of research in recent years in the field of wireless sensor networks (WSNs). It is required for various applications like monitoring of objects placed in indoors and outdoors environments. The main requirement in localisation is to assign a location to each node, since multiple sensor nodes in WSN are used to retrieve information. The aim of this research is to address a WSN localisation problem using various optimisation techniques. The concept of single anchor node placement at the centre of sensing field with its projection using hexagonal pattern is introduced. In this study, a novel hybrid optimisation technique named as dragonfly–firefly algorithm (DA–FA) is proposed. DA is an optimisation algorithm recently suggested based on the dragonfly's static and dynamic swarming behaviour. The suggested hybrid technique combines the exploration capability of explore DA and Firefly algorithm's to exploit to obtain ideal global solutions. To check the effectiveness of DA–FA CEC 2019 benchmark functions are used for comparison with competitive algorithms. DA–FA converges fast and provide optimum solution for most of the benchmark functions. In addition, DA–FA outperforms well in terms of localisation error in comparison to existing localisation solutions.
Vibration reduction of switched reluctance motor under static eccentricity with optimised current harmonic
Authors: Zuo Shuguang , Liu Zexu , Hu Shenglong
Published: April 2020

Aiming at the problems of severe vibration of switched reluctance motor (SRM) and the transfer of the peak vibration caused by newly produced radial magnetic force under static eccentricity (SE), this study proposes a vibration reduction method for SE. First, the analytical relationship between the radial magnetic force harmonics and the current harmonics is derived. 2D Fourier decomposition is used to analyse the temporal–spatial characteristics of force harmonics and the vibration response under SE. Then the expression of the force harmonic, which causes the peak vibration, is used as the optimisation function of current harmonics. According to the analyses in this study, it is difficult to consider vibration reduction and torque simultaneously by single‐order current harmonic optimisation and the unreasonable optimisation range of current will seriously affect the output performance. Therefore, a reasonable optimisation range is set based on the above conclusions and the first five order current harmonics are optimised to improve the effect of vibration suppression further. The results of the finite element simulation verify the effectiveness of this method.
Protection of multi‐terminal remote DC microgrids with overhead lines against temporary and permanent faults
Authors: Saleh Khaled
Published: April 2020

Multi‐terminal low‐voltage DC (MT‐LVDC) remote microgrids are subjected to faults with low current magnitudes. Although such faults do not disturb microgrid steady‐state operation, their continuous existence can lead to permanent (prm) power losses and personnel hazard. Yet, given that faults are often temporary (tmp) on overhead lines, instantaneous de‐energisation of the entire microgrid upon fault detection can result in prolonged loss of infeed, i.e. loss of load. This study proposes a centralised protection scheme to achieve tmp‐fault resilient MT‐LVDC microgrids. The proposed approach is comprised of local intelligent electronic devices (IEDs) at each terminal and a central IED at one of the MT‐LVDC microgrid terminals. Low‐bandwidth communication is utilised between local and central IEDs. Local IEDs are equipped with overcurrent function to take fast protective action under faults with high current magnitudes. On the other hand, the central IED consists of two passive oscillators and DC choppers. The passive oscillators facilitate the detection and identification of tmp and prm faults with low current magnitudes. DC choppers are used for online pole voltage rebalancing upon tmp fault clearance. Testing the centralised protection scheme on a , TN‐S grounded, MT‐LVDC microgrid reveals that the approach is fast, sensitive, selective and resilient under various conditions.
Effects of Cu doping on the properties of NiO film fabricated using the sol–gel method based on the rapid pyrolysis process
Authors: Song Mengsi , Liu Chaoqian , Wang Nan , Lun Tingting , Zhai Xiaona , Ge Qing , Zhang Xiaoyang , Wu Sumei , Liu Shimin , Wang Hualin , Jiang Weiwei , Ding Wanyu
Published: April 2020

The sol–gel method based on the rapid pyrolysis process was adopted to prepare Ni1−x Cux O (x = 0–0.1) films on glass substrates. The effects of Cu doping on the structural, morphological, electrical and optical properties of the films were characterised by X‐ray diffractometer, scanning electron microscope, Hall effect instrument and ultraviolet‐visible spectrophotometer, respectively. The NiO‐based films have a cubic rock salt structure and it was found that the film with x = 0.06 should have minimal residual stress. The transmittance and bandgap of the films decreased with increasing Cu‐doping concentration. In addition, the compactness of the films increased along with the increase of Cu‐doping concentration as a whole. The carrier concentration of the films was almost invariable, but the carrier mobility was determined by the competition between the effects of the morphology and the ionised impurity scattering. The resistivity of the films first decreases and then increases, and the minimum resistivity was 182.1 Ω cm at x = 0.06.
Mixed‐phase BiVO4 nanosheet achieving enhanced photoelectrocatalytic performance
Authors: Wang Yi , Li Junqi , Guo Liu , Zhang Beiyi , Hou Wenfei , Xu Xiaotao
Published: April 2020

The mixed‐phase BiVO4 nanosheet with different ratios of solvents was prepared by a one‐step hydrothermal method. The viscosity of ethylene glycol helps form a homogeneous thin nanosheet, which can be compared with the microstructure of BiVO4 with different ratios of solvents (deionised water and ethylene glycol). Also, both XRD and Raman diagrams indicate that the synthesis of BiVO4 nanosheet constitutes with a mixture of two crystal types. The mixed‐phase BiVO4 possesses higher photocurrent density, smaller electron transport resistance and longer lifetime. Enhanced photoelectrochemical performance can be attributed to the mixed‐phase BiVO4 has a large specific surface area, as well as o‐BiVO4 (orthorhombic BiVO4) and s‐BiVO4 (monocline BiVO4), form heterogeneous junction to promote photogenerated carries separation and reduce the recombination of photogenerated electron–hole.
Generating oxygen vacancies in Cu2+ ‐doped TiO2 hollow spheres for enhanced photocatalytic activity and antimicrobial activity
Authors: Zhang Hongguang , Wang Meng , Xu Feng
Published: April 2020

Developing cheap photocatalysts with highly visible‐light activity is greatly desired for environmental pollution treatment. In this work, the authors designed and synthesised Cu2+ ‐doped TiO2 (Cu‐TiO2) hollow spheres with enhanced photocatalytic activity and antimicrobial activity using a simple hydrothermal process. The X‐ray powder diffraction (XRD) results revealed that Cu‐TiO2 hollow spheres were anatase crystal phase. The Cu2+ ‐doped into TiO2 can be confirmed by XRD, Raman spectra, and UV–Vis spectrum. The photocatalytic activity of Cu‐TiO2 samples was evaluated by the degradation of methyl orange. Comparing to the undoped TiO2, 6% Cu‐TiO2 sample exhibited remarkably high photocatalytic towards methyl orange under simulated sunlight irradiation, which was attributed to the fact that copper ion doping produced numerous oxygen vacancies (VO) in the material. In addition, it also showed improved antibacterial properties against both Gram‐positive Staphylococcus aureus (S.aureus) and Gram‐negative Escherichia coli (E.coli) bacteria. These results establish that Cu2+ doping can obviously improve the photocatalytic performance of TiO2 under simulated sunlight.