bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing caching strategies for stream reasoning with reinforcement learning
Authors: DODARO CARMINE , EITER THOMAS , OGRIS PAUL , SCHEKOTIHIN KONSTANTIN
Published: September 2020

Efficient decision-making over continuously changing data is essential for many application domains such as cyber-physical systems, industry digitalization, etc. Modern stream reasoning frameworks allow one to model and solve various real-world problems using incremental and continuous evaluation of programs as new data arrives in the stream. Applied techniques use, e.g., Datalog-like materialization or truth maintenance algorithms to avoid costly re-computations, thus ensuring low latency and high throughput of a stream reasoner. However, the expressiveness of existing approaches is quite limited and, e.g., they cannot be used to encode problems with constraints, which often appear in practice. In this paper, we suggest a novel approach that uses the Conflict-Driven Constraint Learning (CDCL) to efficiently update legacy solutions by using intelligent management of learned constraints. In particular, we study the applicability of reinforcement learning to continuously assess the utility of learned constraints computed in previous invocations of the solving algorithm for the current one. Evaluations conducted on real-world reconfiguration problems show that providing a CDCL algorithm with relevant learned constraints from previous iterations results in significant performance improvements of the algorithm in stream reasoning scenarios.
Solving the climate crisis: lessons from ozone depletion and COVID-19
Authors: Baldwin Mark P. , Lenton Timothy M.
Published: September 2020

The ‘climate crisis’ describes human-caused global warming and climate change and its consequences. It conveys the sense of urgency surrounding humanity's failure to take sufficient action to slow down, stop and reverse global warming. The leading direct cause of the climate crisis is carbon dioxide (CO2) released as a by-product of burning fossil fuels,i which supply ~87% of the world's energy. The second most important cause of the climate crisis is deforestation to create more land for crops and livestock. The solutions have been stated as simply ‘leave the fossil carbon in the ground’ and ‘end deforestation’. Rather than address fossil fuel supplies, climate policies focus almost exclusively on the demand side, blaming fossil fuel users for greenhouse gas emissions. The fundamental reason that we are not solving the climate crisis is not a lack of green energy solutions. It is that governments continue with energy strategies that prioritize fossil fuels. These entrenched energy policies subsidize the discovery, extraction, transport and sale of fossil fuels, with the aim of ensuring a cheap, plentiful, steady supply of fossil energy into the future. This paper compares the climate crisis to two other environmental crises: ozone depletion and the COVID-19 pandemic. Halting and reversing damage to the ozone layer is one of humanity's greatest environmental success stories. The world's response to COVID-19 demonstrates that it is possible for governments to take decisive action to avert an imminent crisis. The approach to solving both of these crises was the same: (1) identify the precise cause of the problem through expert scientific advice; (2) with support by the public, pass legislation focused on the cause of the problem; and (3) employ a robust feedback mechanism to assess progress and adjust the approach. This is not yet being done to solve the climate crisis, but working within the 2015 Paris Climate Agreement framework, it could be. Every nation can contribute to solving the climate crisis by: (1) changing their energy strategy to green energy sources instead of fossil fuels; and (2) critically reviewing every law, policy and trade agreement (including transport, food production, food sources and land use) that affects the climate crisis.
Sharpness of the Midlithospheric Discontinuities and Craton Evolution in North China
Authors: Sun Weijia , Zhao Liang , Yuan Huaiyu , Fu Li‐Yun
Published: September 2020

The lithospheric layering and evolution of Archean cratons can be effectively constrained by seismic properties. We present fine‐scale lithospheric discontinuity images of the North China Craton (NCC) using the seismic daylight imaging (SDI) technique, which is also known as the autocorrelogram method. With the aid of large‐scale surface‐wave velocity models, the characters of autocorrelograms related to lithospheric discontinuities in the NCC are investigated. Spatial variation in discontinuity characteristics is revealed across the craton. In the modified/destroyed eastern NCC, both the midlithospheric discontinuity (MLD) and the lithosphere‐asthenosphere boundary (LAB) are rather sharp (~2 km). Various dynamic processes, including juvenile underplating, asthenospheric upwelling, and corner flow induced by paleo‐Pacific Plate subduction, may contribute to such sharp interfaces. In the stable western NCC, P wave reflections cannot easily reveal the LAB, suggesting a diffuse (thicker than 30 km) lithosphere‐asthenosphere transition (LAT). Multiple MLDs are also found that may have arisen during craton formation and multiple phases of rejuvenation of the cratonic lithosphere as evidenced by the petrological results. The use of higher‐frequency data enables us to distinguish among the lithospheric discontinuity styles and favor multiple origins of the MLDs and LAB in the cratonic lithosphere.
Location and Setting of the Mars InSight Lander, Instruments, and Landing Site
Authors: Golombek M. , Williams N. , Warner N. H. , Parker T. , Williams M. G. , Daubar I. , Calef F. , Grant J. , Bailey P. , Abarca H. , Deen R. , Ruoff N. , Maki J. , McEwen A. , Baugh N. , Block K. , Tamppari L. , Call J. , Ladewig J. , Stoltz A. , Weems W. A. , Mora‐Sotomayor L. , Torres J. , Johnson M. , Kennedy T. , Sklyanskiy E.
Published: September 2020

Knowing precisely where a spacecraft lands on Mars is important for understanding the regional and local context, setting, and the offset between the inertial and cartographic frames. For the InSight spacecraft, the payload of geophysical and environmental sensors also particularly benefits from knowing exactly where the instruments are located. A ~30 cm/pixel image acquired from orbit after landing clearly resolves the lander and the large circular solar panels. This image was carefully georeferenced to a hierarchically generated and coregistered set of decreasing resolution orthoimages and digital elevation models to the established positive east, planetocentric coordinate system. The lander is located at 4.502384°N, 135.623447°E at an elevation of −2,613.426 m with respect to the geoid in Elysium Planitia. Instrument locations (and the magnetometer orientation) are derived by transforming from Instrument Deployment Arm, spacecraft mechanical, and site frames into the cartographic frame. A viewshed created from 1.5 m above the lander and the high‐resolution orbital digital elevation model shows the lander is on a shallow regional slope down to the east that reveals crater rims on the east horizon ~400 m and 2.4 km away. A slope up to the north limits the horizon to about 50 m away where three rocks and an eolian bedform are visible on the rim of a degraded crater rim. Azimuths to rocks and craters identified in both surface panoramas and high‐resolution orbital images reveal that north in the site frame and the cartographic frame are the same (within 1°).
Is Enhanced Predictability of the Amundsen Sea Low in Subseasonal to Seasonal Hindcasts Linked to Stratosphere‐Troposphere Coupling?
Authors: Wang Shaoyin , Liu Jiping , Cheng Xiao , Kerzenmacher Tobias , Braesicke Peter
Published: September 2020

The Amundsen Sea low (ASL) is one of the key components of the Antarctic surface climate. Here, we assess the subseasonal to seasonal (S2S) predictive skill of the ASL in two state‐of‐the‐art forecasting systems based on the anomaly correlation coefficient (ACC). It is found that the ASL predictability during austral spring is higher than in the other seasons with lead times ranging from 1 to 4 weeks. The spring ASL predictability has an ACC of about 0.6 with lead times of 1–2 weeks and about 0.44 with lead times of 3–4 weeks. The enhanced ASL predictability during austral spring is mainly due to the strengthening of stratosphere‐troposphere coupling, coincident with a weakened stratospheric polar night jet and increased wave‐mean flow interactions in the stratosphere. This study demonstrates that the stratosphere‐troposphere coupling provides an important source of predictability for the Antarctic surface weather and climate on S2S timescale.
Plasma and Field Observations in the Magnetospheric Source Region of a Stable Auroral Red (SAR) Arc by the Arase Satellite on 28 March 2017
Authors: Inaba Yudai , Shiokawa Kazuo , Oyama Shin‐ichiro , Otsuka Yuichi , Oksanen Arto , Shinbori Atsuki , Gololobov Artem Yu , Miyoshi Yoshizumi , Kazama Yoichi , Wang Shiang‐Yu , Tam Sunny W. Y. , Chang Tzu‐Fang , Wang Bo‐Jhou , Yokota Shoichiro , Kasahara Satoshi , Keika Kunihiro , Hori Tomoaki , Matsuoka Ayako , Kasahara Yoshiya , Kumamoto Atsushi , Kasaba Yasumasa , Tsuchiya Fuminori , Shoji Masafumi , Shinohara Iku , Stolle Claudia
Published: September 2020

A stable auroral red (SAR) arc is an aurora with a dominant 630 nm emission at subauroral latitudes. SAR arcs have been considered to occur due to the spatial overlap between the plasmasphere and the ring‐current ions. In the overlap region, plasmaspheric electrons are heated by ring‐current ions or plasma waves, and their energy is then transferred down to the ionosphere where it causes oxygen red emission. However, there have been no study conducted so far that quantitatively examined plasma and electromagnetic fields in the magnetosphere associated with SAR arc. In this paper, we report the first quantitative evaluation of conjugate measurements of a SAR arc observed at 2204 UT on 28 March 2017 and investigate its source region using an all‐sky imager at Nyrölä (magnetic latitude: 59.4°N), Finland, and the Arase satellite. The Arase observation shows that the SAR arc appeared in the overlap region between a plasmaspheric plume and the ring‐current ions and that electromagnetic ion cyclotron waves and kinetic Alfven waves were not observed above the SAR arc. The SAR arc was located at the ionospheric trough minimum identified from a total electron content map obtained by the GNSS receiver network. The Swarm satellite flying in the ionosphere also passed the SAR arc at ~2320 UT and observed a decrease in electron density and an increase in electron temperature during the SAR‐arc crossing. These observations suggest that the heating of plasmaspheric electrons via Coulomb collision with ring‐current ions is the most plausible mechanism for the SAR‐arc generation.
Change in Total Electron Content During the 26 December 2019 Solar Eclipse: Constraints From GNSS Observations and Comparison With SAMI3 Model Results
Authors: Senapati Batakrushna , Huba J. D. , Kundu Bhaskar , Gahalaut Vineet K. , Panda Dibyashakti , Mondal Saroj Kumar , Catherine Joshi K.
Published: September 2020

We report spatiotemporal variation in the total electron content (TEC) in ionosphere caused by the 26 December 2019 annular solar eclipse, seen over most of the Southeast Asia. Sparsely distributed network of the Global Navigation Satellite System (GNSS) sites located on the continental parts and on islands documented the transhemispheric coellipse changes in the ionospheric electron density. A significant depletion in TEC of ~6–8 TECU (1 TECU = 1 × 1016 electrons m−2) is observed along the path of the eclipse shadow. Simulations using the SAMI3 model are consistent with the observations of TEC depletion. The model also predicted a magnetically conjugate region of marginal increased TEC of ~0.2–0.3 TECU around northern Japan and adjacent Pacific Ocean, which is also consistent with the ground‐based GNSS observations in that region.
Permeability Variations in Illite‐Bearing Sandstone: Effects of Temperature and NaCl Fluid Salinity
Authors: Cheng Chaojie , Milsch Harald
Published: September 2020

Temperature changes and variations in pore fluid salinity may negatively affect the permeability of clay‐bearing sandstones with implications for natural fluid flow and geotechnical applications alike. In this study these factors are investigated for a sandstone dominated by illite as the clay phase. Systematic long‐term flow‐through experiments were conducted and complemented with comprehensive microstructural investigations and the application of Derjaguin‐Landau‐Verwey‐Overbeek (DLVO) theory to explain mechanistically the observed permeability changes. Initially, sample permeability was not affected by low pore fluid salinity indicating strong attraction of the illite particles to the pore walls as supported by electron microprobe analysis (EMPA). Increasing temperature up to 145°C resulted in an irreversible permeability decrease by 1.5 orders of magnitude regardless of the pore fluid composition (i.e., deionized water and 2 M NaCl solution). Subsequently diluting the high salinity pore fluid to below 0.5 M yielded an additional permeability decline by 1.5 orders of magnitude, both at 145°C and after cooling to room temperature. By applying scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) thermo‐mechanical pore throat closure and illite particle migration were identified as independently operating mechanisms responsible for observed permeability changes during heating and dilution, respectively. These observations indicate that permeability of illite‐bearing sandstones will be impaired by heating and exposure to low salinity pore fluids. In addition, chemically induced permeability variations proved to be path dependent with respect to the applied succession of fluid salinity changes.
Circulation and Hydrography in the Western South Atlantic Shelf and Export to the Deep Adjacent Ocean: 30°S to 40°S
Authors: Berden Giuliana , Charo Marcela , Möller Osmar O. , Piola Alberto R.
Published: September 2020

High sea surface chlorophyll concentration on the Argentine Continental Shelf frequently extends to the deep ocean in the vicinity of the Brazil/Malvinas Confluence (BMC). The offshore transport of shelf waters likely plays a key role in the biogeochemical balance of the western South Atlantic and promotes the offshore transport of planktonic species. We analyze data from an oceanographic survey carried out in the western South Atlantic shelf between 31°S and 38°S in October 2013. We describe the distribution and circulation of the water masses and focus on the exchanges with the open ocean. On‐shelf subsurface intrusions of oceanic waters and river discharge supply nutrients to the shelf. A low‐salinity tongue of Río de la Plata (RDP) waters extends northward to 32°S. Below these waters Subantarctic and Subtropical Shelf Waters (SASW and STSW) meet to form the Subtropical Shelf Front. The main SASW branch, oversaturated in oxygen and with high‐fluorescence mixes with a detachment of Brazil Current waters at 38°S and is exported offshore along the BMC. A second branch of SASW reaches 33°S mixing along its way with RDP and STSW and returns southward after splitting into an onshore and an offshore branch. The offshore branch is exported to the open ocean through the BMC. These export routes are in overall qualitative agreement with those indicated by a high‐resolution reanalysis. We estimate a net off‐shelf transport (geostrophic [96.2%] plus Ekman [3.8%]) of 3.44 Sv to the open ocean between 32.1°S and 37.7°S. The majority of the offshore flow occurs between 34.7°S and 37.7°S.
Cooling and Moistening of the Planetary Boundary Layer in Interior Alaska Due to a Postfire Change in Surface Energy Exchange
Authors: Ueyama Masahito , Yamamori Takahiro , Iwata Hiroki , Harazono Yoshinobu
Published: September 2020

Key Points

Regional climate via PBL dynamics was estimated using measurements of surface energy exchange and mixed‐layer model in interior Alaska

Regional cooling and moistening were estimated due to fire‐induced land cover change from a mature forest to postfire young forest

Albedo and increased evapotranspiration caused the regional cooling and moistening effects
Entrainment and Dynamics of Ocean‐Derived Impurities Within Europa's Ice Shell
Authors: Buffo J. J. , Schmidt B. E. , Huber C. , Walker C. C.
Published: September 2020

Compositional heterogeneities within Europa's ice shell likely impact the dynamics and habitability of the ice and subsurface ocean, but the total inventory and distribution of impurities within the shell are unknown. In sea ice on Earth, the thermochemical environment at the ice‐ocean interface governs impurity entrainment into the ice. Here, we simulate Europa's ice‐ocean interface and bound the impurity load (1.053–14.72 g/kg [parts per thousand weight percent, or ppt] bulk ice shell salinity) and bulk salinity profile of the ice shell. We derive constitutive equations that predict ice composition as a function of the ice shell thermal gradient and ocean composition. We show that evolving solidification rates of the ocean and hydrologic features within the shell produce compositional variations (ice bulk salinities of 5–50% of the ocean salinity) that can affect the material properties of the ice. As the shell thickens, less salt is entrained at the ice‐ocean interface, which implies Europa's ice shell is compositionally homogeneous below ~1 km. Conversely, the solidification of water filled fractures or lenses introduces substantial compositional variations within the ice shell, creating gradients in mechanical and thermal properties within the ice shell that could help initiate and sustain geological activity. Our results suggest that ocean materials entrained within Europa's ice shell affect the formation of geologic terrain and that these structures could be confirmed by planned spacecraft observations.
Vertical Propagation of Wave Perturbations in the Middle Atmosphere on Mars by MAVEN/IUVS
Authors: Nakagawa Hiromu , Terada Naoki , Jain Sonal K. , Schneider Nicholas M. , Montmessin Franck , Yelle Roger V. , Jiang Fayu , Verdier Loic , England Scott L. , Seki Kanako , Fujiwara Hitoshi , Imamura Takeshi , Yoshida Nao , Kuroda Takeshi , Terada Kaori , Gröller Hannes , Deighan Justin , Jakosky Bruce M.
Published: September 2020

This work offers the first in‐depth study of the global characteristics of wave perturbations in temperature profiles at 20–140 km altitudes derived from the Imaging Ultraviolet Spectrograph (IUVS) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. The peak amplitudes of waves seen in temperature profiles exceed 20% of the mean background, especially on the nightside, which is larger than those in Earth's mesosphere and thermosphere. The wave perturbations generate an instability layer around 70–100 km on the nightside, which potentially causes wave‐breaking and turbulences. Our results highlighted a seasonal variation in the latitudinal distribution of nightside perturbations. Amplitudes of wave perturbations were found to be large in the northern low‐latitude region and the southern polar region during the first half of the year (Ls = 0–180°). An increase of waves in the spectral density was found in southern low‐latitude regions in the latter half of the year (Ls = 180–360°). Vertical wavenumber spectral density in the Martian middle atmosphere shows a power‐law dependence with a logarithmic spectral slope of −3, similar to the features seen in the Earth's atmosphere. The derived spectral power density suggests the longer waves growing with height while the effective dissipation of shorter waves occurs. The strong CO2 15‐micron band cooling can effectively dissipate shorter waves. In contrast, the spectral power density at longer waves suggests an amplitude growth with height of unsaturated waves up to the lower thermosphere.
Telomere dysfunction activates YAP1 to drive tissue inflammation
Authors: Chakravarti Deepavali , Hu Baoli , Mao Xizeng , Rashid Asif , Li Jiexi , Li Jun , Liao Wen-ting , Whitley Elizabeth M. , Dey Prasenjit , Hou Pingping , LaBella Kyle A. , Chang Andrew , Wang Guocan , Spring Denise J. , Deng Pingna , Zhao Di , Liang Xin , Lan Zhengdao , Lin Yiyun , Sarkar Sharmistha , Terranova Christopher , Deribe Yonathan Lissanu , Blutt Sarah E. , Okhuysen Pablo , Zhang Jianhua , Vilar Eduardo , Nielsen Ole Haagen , Dupont Andrew , Younes Mamoun , Patel Kalyani R. , Shroyer Noah F. , Rai Kunal , Estes Mary K. , Wang Y. Alan , Bertuch Alison A. , DePinho Ronald A.
Published: September 2020

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.
Single-cell sequencing reveals clonal expansions of pro-inflammatory synovial CD8 T cells expressing tissue-homing receptors in psoriatic arthritis
Authors: Penkava Frank , Velasco-Herrera Martin Del Castillo , Young Matthew D. , Yager Nicole , Nwosu Lilian N. , Pratt Arthur G. , Lara Alicia Lledo , Guzzo Charlotte , Maroof Ash , Mamanova Lira , Cole Suzanne , Efremova Mirjana , Simone Davide , Filer Andrew , Brown Chrysothemis C. , Croxford Andrew L. , Isaacs John D. , Teichmann Sarah , Bowness Paul , Behjati Sam , Hussein Al-Mossawi M.
Published: September 2020

Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. Here we use complementary single-cell approaches to study leukocytes from PsA joints. Mass cytometry demonstrates a 3-fold expansion of memory CD8 T cells in the joints of PsA patients compared to peripheral blood. Meanwhile, droplet-based and plate-based single-cell RNA sequencing of paired T cell receptor alpha and beta chain sequences show pronounced CD8 T cell clonal expansions within the joints. Transcriptome analyses find these expanded synovial CD8 T cells to express cycling, activation, tissue-homing and tissue residency markers. T cell receptor sequence comparison between patients identifies clonal convergence. Finally, chemokine receptor CXCR3 is upregulated in the expanded synovial CD8 T cells, while two CXCR3 ligands, CXCL9 and CXCL10, are elevated in PsA synovial fluid. Our data thus provide a quantitative molecular insight into the cellular immune landscape of psoriatic arthritis.
Near-atomic resolution structures of interdigitated nucleosome fibres
Authors: Adhireksan Zenita , Sharma Deepti , Lee Phoi Leng , Davey Curt A.
Published: September 2020

Chromosome structure at the multi-nucleosomal level has remained ambiguous in spite of its central role in epigenetic regulation and genome dynamics. Recent investigations of chromatin architecture portray diverse modes of interaction within and between nucleosome chains, but how this is realized at the atomic level is unclear. Here we present near-atomic resolution crystal structures of nucleosome fibres that assemble from cohesive-ended dinucleosomes with and without linker histone. As opposed to adopting folded helical ‘30 nm’ structures, the fibres instead assume open zigzag conformations that are interdigitated with one another. Zigzag conformations obviate extreme bending of the linker DNA, while linker DNA size (nucleosome repeat length) dictates fibre configuration and thus fibre–fibre packing, which is supported by variable linker histone binding. This suggests that nucleosome chains have a predisposition to interdigitate with specific characteristics under condensing conditions, which rationalizes observations of local chromosome architecture and the general heterogeneity of chromatin structure.
Low-noise GaAs quantum dots for quantum photonics
Authors: Zhai Liang , Löbl Matthias C. , Nguyen Giang N. , Ritzmann Julian , Javadi Alisa , Spinnler Clemens , Wieck Andreas D. , Ludwig Arne , Warburton Richard J.
Published: September 2020

Quantum dots are both excellent single-photon sources and hosts for single spins. This combination enables the deterministic generation of Raman-photons—bandwidth-matched to an atomic quantum-memory—and the generation of photon cluster states, a resource in quantum communication and measurement-based quantum computing. GaAs quantum dots in AlGaAs can be matched in frequency to a rubidium-based photon memory, and have potentially improved electron spin coherence compared to the widely used InGaAs quantum dots. However, their charge stability and optical linewidths are typically much worse than for their InGaAs counterparts. Here, we embed GaAs quantum dots into an n-i-p-diode specially designed for low-temperature operation. We demonstrate ultra-low noise behaviour: charge control via Coulomb blockade, close-to lifetime-limited linewidths, and no blinking. We observe high-fidelity optical electron-spin initialisation and long electron-spin lifetimes for these quantum dots. Our work establishes a materials platform for low-noise quantum photonics close to the red part of the spectrum.
COVID-19 image classification using deep features and fractional-order marine predators algorithm
Authors: Sahlol Ahmed T. , Yousri Dalia , Ewees Ahmed A. , Al-qaness Mohammed A. A. , Damasevicius Robertas , Elaziz Mohamed Abd
Published: September 2020

Currently, we witness the severe spread of the pandemic of the new Corona virus, COVID-19, which causes dangerous symptoms to humans and animals, its complications may lead to death. Although convolutional neural networks (CNNs) is considered the current state-of-the-art image classification technique, it needs massive computational cost for deployment and training. In this paper, we propose an improved hybrid classification approach for COVID-19 images by combining the strengths of CNNs (using a powerful architecture called Inception) to extract features and a swarm-based feature selection algorithm (Marine Predators Algorithm) to select the most relevant features. A combination of fractional-order and marine predators algorithm (FO-MPA) is considered an integration among a robust tool in mathematics named fractional-order calculus (FO). The proposed approach was evaluated on two public COVID-19 X-ray datasets which achieves both high performance and reduction of computational complexity. The two datasets consist of X-ray COVID-19 images by international Cardiothoracic radiologist, researchers and others published on Kaggle. The proposed approach selected successfully 130 and 86 out of 51 K features extracted by inception from dataset 1 and dataset 2, while improving classification accuracy at the same time. The results are the best achieved on these datasets when compared to a set of recent feature selection algorithms. By achieving 98.7%, 98.2% and 99.6%, 99% of classification accuracy and F-Score for dataset 1 and dataset 2, respectively, the proposed approach outperforms several CNNs and all recent works on COVID-19 images.
Enhancement of photovoltage by electronic structure evolution in multiferroic Mn-doped BiFeO3 thin films
Authors: Nakashima Seiji , Higuchi Tohru , Yasui Akira , Kinoshita Toyohiko , Shimizu Masaru , Fujisawa Hironori
Published: September 2020

The bulk photovoltaic effect (BPVE) is a mechanism of recent focus for novel solar cells that exceed the power conversion efficiency of p–n junction solar cells because of the quantum mechanical effect to generate photocurrent known as shift current. Ferroelectrics are receiving attention again because of their high voltage generation by the BPVE and converse piezoelectric effect to realize high performance optical actuators. We have investigated the BPVE in ferroelectric BiFeO3(BFO) single crystal thin films, whereby the photovoltage was enhanced by Mn doping, and 852 V generation was demonstrated at 80 K. The enhancement mechanism was also investigated using soft and hard X-ray photoelectron spectroscopy (SXPES, HAXPES), and soft X-ray absorption spectroscopy with synchrotron radiation. This report reveals a way to new voltage source applications employing the BPVE for high impedance devices with ferroelectrics. Important aspects for designing ferroelectric materials by impurity doping are also discussed.
Design and experimental analysis of dual-band polarization converting metasurface for microwave applications
Authors: Khan Bilawal , Kamal Babar , Ullah Sadiq , Khan Imran , Shah Jawad Ali , Chen Jingdong
Published: September 2020

The manipulation of polarization state of electromagnetic waves is of great importance in many practical applications. In this paper, the reflection characteristics of a thin and dual-band metasurface are examined in the microwave frequency regime. The metasurface consists of a 22 × 22 element array of periodic unit cells. The geometry of the unit cell consists of three layers, including a 45° inclined dipole shape metal patch on top, which is backed by a 1.6 mm thick FR-4 substrate in the middle, and a fully reflective metallic mirror at the bottom. The proposed surface is exposed to horizontally (x) or vertically (y) polarized plane waves and the co and cross polarization reflection coefficients of the reflected waves are investigated experimentally in the 6–26 GHz frequency range. The metasurface is designed to convert incident waves of known polarization state (horizontal or vertical) to orthogonal polarization state (vertical and horizontal) in two distinct frequency bands, i.e. 7.1–8 GHz and 13.3–25.8 GHz. In these two frequency bands the simulated and experimental results are in good agreement. The polarization conversion ratio (PCR) of the surface is greater than 95% in the targeted frequency bands. A detailed parametric analysis of the metasurface is also discussed in this work and it has been estimated that the surface has the additional ability to convert linearly polarized waves to circularly polarized waves at several distinct frequencies. The proposed metasurface can be utilized in sensor applications, stealth technology, electromagnetic measurements, and antennas design.
The combined effect of obesity and aging on human sperm DNA methylation signatures: inclusion of BMI in the paternal germ line age prediction model
Authors: Salas-Huetos Albert , James Emma R. , Broberg Dallin S. , Aston Kenneth I. , Carrell Douglas T. , Jenkins Timothy G.
Published: September 2020

Male aging and obesity have both been shown to contribute to declines in fertility in men. Recent work in aging has shown consistent epigenetic changes to sperm as a man ages. In fact, our lab has built a tool that utilizes DNA methylation signatures from sperm to effectively predict an individual’s age. Herein, we performed this preliminary cohort study to determine if increased BMI accelerates the epigenetic aging in sperm. A total of 96 participants were divided into four age groups (22–24, 30, 40–41, and > 48 years of age) and additionally parsed into two BMI sub-categories (normal and high/obese). We found no statistically significant epigenetic age acceleration. However, it is important to note that within each age category, high BMI individuals were predicted to be older on average than their actual age (~ 1.4 years), which was not observed in the normal BMI group. To further investigate this, we re-trained a model using only the present data with and without BMI as a feature. We found a modest but non-significant improvement in prediction with BMI [r2 = 0.8814, mean absolute error (MAE) = 3.2913] compared to prediction without BMI (r2 = 0.8739, MAE = 3.3567). Future studies with higher numbers of age-matched individuals are needed to definitively understand the impact of BMI on epigenetic aging in sperm.
Initiation of reticular and spider veins, incompetent perforantes and varicose veins in the saphenous vein network of the rat
Authors: Patai Bernadett Bettina , Dornyei Gabriella , Tokes Anna-Maria , Hetthessy Judit Reka , Fees Alexander , Nadasy Gyorgy L.
Published: September 2020

In an attempt to induce experimental varicosity, reverse perforant vein development was initiated in the rat leg by applying a chronic (14 and 32 weeks) partial stricture on the main branch of the deep femoral vein. At surfacing of the incompetent perforantes, typical reticular vein plaques and spider veins were identified by video-microscopy and quantitative histology. Deep vein blood was channeled by them into the saphenous vein system, the extra flow deforming these vessels, causing local dilations and broken course, even undulations of larger branches.
Active meta polarizer for terahertz frequencies
Authors: Wong Hang , Wang Kai Xu , Huitema Laure , Crunteanu Aurelian
Published: September 2020

Active meta polarizers based on phase-change materials have recently led to emerging developments in terahertz devices and systems for imaging, security, and high-speed communications. Existing technologies of adaptive control of meta polarizers are limited to the complexity of external stimuli. Here, we introduce an active terahertz polarizer consisting of a single layer of large array patterns of vanadium dioxide material integrated with metallic patch matrix to dynamically reconfigure the polarization of the terahertz waves. The proposed active polarizer is simple in structure and can independently manipulate the polarization of the incident THz waves in two orthogonal directions. In addition, the device can also be performing as a highly efficient reflector at the same frequencies. We demonstrate that efficient and fast polarization changes of THz waves can be achieved over a wide operating bandwidth. Compared with other active polarizers using mechanical, optical and thermal controls, it can be conveniently manipulated with DC bias without any external actuators, intense laser source or heater. Therefore, with the advantages of high efficiency, compact size, low loss, low cost and fast response, the proposed polarizer can be highly integrative and practical to operate within adaptive terahertz circuits and systems.
The use of light spectrum blocking films to reduce populations of Drosophila suzukii Matsumura in fruit crops
Authors: Fountain Michelle T. , Badiee Amir , Hemer Sebastian , Delgado Alvaro , Mangan Michael , Dowding Colin , Davis Frederick , Pearson Simon
Published: September 2020

Spotted wing drosophila, Drosophila suzukii, is a serious invasive pest impacting the production of multiple fruit crops, including soft and stone fruits such as strawberries, raspberries and cherries. Effective control is challenging and reliant on integrated pest management which includes the use of an ever decreasing number of approved insecticides. New means to reduce the impact of this pest that can be integrated into control strategies are urgently required. In many production regions, including the UK, soft fruit are typically grown inside tunnels clad with polyethylene based materials. These can be modified to filter specific wavebands of light. We investigated whether targeted spectral modifications to cladding materials that disrupt insect vision could reduce the incidence of D. suzukii. We present a novel approach that starts from a neuroscientific investigation of insect sensory systems and ends with infield testing of new cladding materials inspired by the biological data. We show D. suzukii are predominantly sensitive to wavelengths below 405 nm (ultraviolet) and above 565 nm (orange & red) and that targeted blocking of lower wavebands (up to 430 nm) using light restricting materials reduces pest populations up to 73% in field trials.
Theoretical insights of codoping to modulate electronic structure of $$\hbox {TiO}_2$$ and $$\hbox {SrTiO}_3$$ for enhanced photocatalytic efficiency
Authors: Kumar Manish , Basera Pooja , Saini Shikha , Bhattacharya Saswata
Published: September 2020

$$\hbox {TiO}_2$$

TiO
2

and $$\hbox {SrTiO}_3$$

SrTiO
3

are well known materials in the field of photocatalysis due to their exceptional electronic structure, high chemical stability, non-toxicity and low cost. However, owing to the wide band gap, these can be utilized only in the UV region. Thus, it’s necessary to expand their optical response in visible region by reducing their band gap through doping with metals, nonmetals or the combination of different elements, while retaining intact the photocatalytic efficiency. We report here, the codoping of a metal and a nonmetal in anatase $$\hbox {TiO}_2$$

TiO
2

and $$\hbox {SrTiO}_3$$

SrTiO
3

for efficient photocatalytic water splitting using hybrid density functional theory and ab initio atomistic thermodynamics. The latter ensures to capture the environmental effect to understand thermodynamic stability of the charged defects at a realistic condition. We have observed that the charged defects are stable in addition to neutral defects in anatase $$\hbox {TiO}_2$$

TiO
2

and the codopants act as donor as well as acceptor depending on the nature of doping (p-type or n-type). However, the most stable codopants in $$\hbox {SrTiO}_3$$

SrTiO
3

mostly act as donor. Our results reveal that despite the response in visible light region, the codoping in $$\hbox {TiO}_2$$

TiO
2

and $$\hbox {SrTiO}_3$$

SrTiO
3

cannot always enhance the photocatalytic activity due to either the formation of recombination centers or the large shift in the conduction band minimum or valence band maximum. Amongst various metal-nonmetal combinations, $$\hbox {Mn}_\text {Ti}\hbox {S}_\text {O}$$

Mn
Ti

S
O

(i.e. Mn is substituted at Ti site and S is substituted at O site), $$\hbox {S}_\text {O}$$

S
O

in anatase $$\hbox {TiO}_2$$

TiO
2

and $$\hbox {Mn}_\text {Ti}\hbox {S}_\text {O}$$

Mn
Ti

S
O

, $$\hbox {Mn}_\text {Sr}\hbox {N}_\text {O}$$

Mn
Sr

N
O

in $$\hbox {SrTiO}_3$$

SrTiO
3

are the most potent candidates to enhance the photocatalytic efficiency of anatase $$\hbox {TiO}_2$$

TiO
2

and $$\hbox {SrTiO}_3$$

SrTiO
3

under visible light irradiation.
Electrophysiological assessment of temporal envelope processing in cochlear implant users
Authors: Gransier Robin , Carlyon Robert P. , Wouters Jan
Published: September 2020

Cochlear-implant (CI) users rely on temporal envelope modulations (TEMs) to understand speech, and clinical outcomes depend on the accuracy with which these TEMs are encoded by the electrically-stimulated neural ensembles. Non-invasive EEG measures of this encoding could help clinicians identify and disable electrodes that evoke poor neural responses so as to improve CI outcomes. However, recording EEG during CI stimulation reveals huge stimulation artifacts that are up to orders of magnitude larger than the neural response. Here we used a custom-built EEG system having an exceptionally high sample rate to accurately measure the artefact, which we then removed using linear interpolation so as to reveal the neural response during continuous electrical stimulation. In ten adult CI users, we measured the 40-Hz electrically evoked auditory steady-state response (eASSR) and electrically evoked auditory change complex (eACC) to amplitude-modulated 900-pulses-per-second pulse trains, stimulated in monopolar mode (i.e. the clinical default), and at different modulation depths. We successfully measured artifact-free 40-Hz eASSRs and eACCs. Moreover, we found that the 40-Hz eASSR, in contrast to the eACC, showed substantial responses even at shallow modulation depths. We argue that the 40-Hz eASSR is a clinically feasible objective measure to assess TEM encoding in CI users.
Thyroxine binding to type III iodothyronine deiodinase
Authors: Bayse Craig A. , Marsan Eric S. , Garcia Jenna R. , Tran-Thompson Alexis T.
Published: September 2020

Iodothyronine deiodinases (Dios) are important selenoproteins that control the concentration of the active thyroid hormone (TH) triiodothyronine through regioselective deiodination. The X-ray structure of a truncated monomer of Type III Dio (Dio3), which deiodinates TH inner rings through a selenocysteine (Sec) residue, revealed a thioredoxin-fold catalytic domain supplemented with an unstructured Ω-loop. Loop dynamics are driven by interactions of the conserved Trp207 with solvent in multi-microsecond molecular dynamics simulations of the Dio3 thioredoxin(Trx)-fold domain. Hydrogen bonding interactions of Glu200 with residues conserved across the Dio family anchor the loop’s N-terminus to the active site Ser-Cys-Thr-Sec sequence. A key long-lived loop conformation coincides with the opening of a cryptic pocket that accommodates thyroxine (T4) through an I⋯Se halogen bond to Sec170 and the amino acid group with a polar cleft. The Dio3-T4complex is stabilized by an I⋯O halogen bond between an outer ring iodine and Asp211, consistent with Dio3 selectivity for inner ring deiodination. Non-conservation of residues, such as Asp211, in other Dio types in the flexible portion of the loop sequence suggests a mechanism for regioselectivity through Dio type-specific loop conformations. Cys168 is proposed to attack the selenenyl iodide intermediate to regenerate Dio3 based upon structural comparison with related Trx-fold proteins.
Luteolin modulates SERCA2a via Sp1 upregulation to attenuate myocardial ischemia/reperfusion injury in mice
Authors: Hu Ya , Zhang Chengmeng , Zhu Hong , Wang Shuai , Zhou Yao , Zhao Jiaqi , Xia Yong , Li Dongye
Published: September 2020

The sarco/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) is responsible for calcium transport during excitation–contraction coupling and is essential for maintaining myocardial systolic/diastolic function and intracellular Ca2+ levels. Therefore, it is important to investigate mechanisms whereby luteolin modulates SERCA2a expression to attenuate myocardial ischemia/reperfusion injury. C57BL/6j mice were randomly divided into eight groups. The expression and activity of SERCA2a was measured to assess interactions between the SERCA2a promoter and the Sp1 transcription factor, and the regulatory effects of luteolin. We used serum LDH release, serum cardiac troponin I level, hemodynamic data, myocardial infarction size and apoptosis-related indices to measure SERCA2a cardio-protective effects of luteolin pretreatment. Sp1 binding to SERCA2a promoter under ischemia/reperfusion conditions in the presence or absence of luteolin was analyzed by chromatin immunoprecipitation. Our experimental results indicated that during myocardial ischemia/reperfusion injury, luteolin pretreatment upregulated the expression levels of SERCA2a and Sp1. Sp1 overexpression enhanced the expression of SERCA2a at the transcriptional level. Luteolin pretreatment reversed the expression of SERCA2a through the increased expression of Sp1. Moreover, we demonstrated that luteolin pretreatment appeared to exert myocardial protective effects by upregulating the transcriptional activity of SERCA2a, via Sp1. In conclusion, during myocardial ischemia/reperfusion, Sp1 appeared to downregulate the expression of SERCA2a. Luteolin pretreatment was shown to improve SERCA2a expression via the upregulation of Sp1 to attenuate myocardial ischemia/reperfusion injury.
Changes in endothelial function during educational hospitalization and the contributor to improvement of endothelial function in type 2 diabetes mellitus
Authors: Goshima Yukiko , Okada Yosuke , Torimoto Keiichi , Fujino Yoshihisa , Tanaka Yoshiya
Published: September 2020

Only a few reports have examined vascular endothelial function before and after educational hospitalization and the factors that affect it in patients with type 2 diabetes mellitus (T2DM). The aim of this study was to assess vascular endothelial function before and after educational hospitalization and identify factors that affect it. In 65 patients with T2DM who underwent peripheral arterial tonometry (EndoPAT) before and after hospitalization, vascular endothelial function (reactive hyperemia index [RHI]), glucose metabolism, lipid metabolism, and blood pressure were assessed before and after hospitalization. The primary endpoint was hospitalization-induced changes in vascular endothelial function. Educational hospitalization significantly improved the natural logarithmically scaled RHI (L_RHI) from 0.555 ± 0.212 to 0.625 ± 0.245 (p = 0.012). Multivariable logistic regression analysis identified hypoglycemia during hospitalization as the single factor that significantly altered vascular endothelial function (p = 0.019). The odds of achieving normal vascular endothelial function were 0.08 times lower (95% confidence interval, 0.01–0.67) for each episode of hypoglycemia. Furthermore, multivariable analysis identified hypoglycemia during hospitalization as the single factor that worsened L_RHI. Our study showed that educational hospitalization of patients with T2DM improved vascular endothelial function, and that the development of hypoglycemic episodes had a significant negative impact on normalization of vascular endothelial function.
Distribution and relative expression of vasoactive receptors on arteries
Authors: Liu Xinhao , Luo Dan , Zhang Jie , Du Lei
Published: September 2020

Arterial tone is regulated by multiple ligand-receptor interactions, and its dysregulation is involved in ischemic conditions such as acute coronary spasm or syndrome. Understanding the distribution of vasoactive receptors on different arteries may help guide the development of tissue-specific vasoactive treatments against arterial dysfunction. Tissues were harvested from coronary, mesenteric, pulmonary, renal and peripheral human artery (n = 6 samples of each) and examined using a human antibody array to determine the expression of 29 vasoactive receptors and 3 endothelin ligands. Across all types of arteries, outer diameter ranged from 2.24 ± 0.63 to 3.65 ± 0.40 mm, and AVPR1A was the most abundant receptor. The expression level of AVPR1A in pulmonary artery was similar to that in renal artery, 2.2 times that in mesenteric artery, 1.9 times that in peripheral artery, and 2.2 times that in coronary artery. Endothelin-1 was expressed at significantly higher levels in pulmonary artery than peripheral artery (8.8 times), mesenteric artery (5.3 times), renal artery (7.9 times), and coronary artery (2.4 times). Expression of ADRA2B was significantly higher in coronary artery than peripheral artery. Immunohistochemistry revealed abundant ADRA2B in coronary artery, especially vessels with diameters below 50 μm, but not in myocardium. ADRA2C, in contrast, was expressed in both myocardium and blood vessels. The high expression of ADRA2B in coronary artery but not myocardium highlights the need to further characterize its function. Our results help establish the distribution and relative levels of tone-related receptors in different types of arteries, which may guide artery-specific treatments.