bluuebunny/crossref_metadata_2025 huggingface dataset:
Mit Einzelzell-Genomik die Entscheidungen von Zellen verfolgen
Authors: Hu Bo , Junker Jan Philipp
Published: February 2021

During embryonic development, cells need to take a series of successive fate decisions in order to reach their final differentiated stage. Understanding the processes that give rise to the multitude of different cell types in an organism is a major question in developmental biology. New methods in single cell genomics enable researchers to decipher the transcriptional programs and gene regulatory mechanisms that underlie cell fate decisions during embryonic development.
Den molekularen Wirtszellveränderungen durch SARS-CoV-2 auf der Spur
Authors: Klann Kevin , Münch Christian
Published: February 2021

Upon infection with SARS-CoV-2, a variety of changes happen inside the host cell. The virus hijacks host cell pathways for driving its own replication, while the host counteracts with response mechanisms. To gain a comprehensive understanding of COVID-19, caused by SARS-CoV-2 infection, and develop therapeutic strategies, it is crucial to observe these systematic changes in their entirety. In our recent studies, we followed the effects of SARS-CoV-2 infection on the human proteome, which led to the identification of several drugs that abolished viral proliferation in cells.
Clay Analysis of Upper Assam Basin for Chemical Enhanced Oil Recovery
Authors: Hazarika Kalpajit , Gogoi Subrata Borgohain
Published: February 2021

The success and failure of different chemical enhanced oil recovery (CEOR) techniques can control to a large extent by the presence of different types of clay, its surface area and the reactivity of the clay with the injected chemicals during CEOR techniques. Therefore, reservoir clay analysis is important to study the CEOR process in general and to formulate the CEOR slug in particular. This study pertains to the underground porous media of upper Assam basin. In this paper effective porosity, absolute permeability, minerals and clays present in porous media is studied. Effective porosities were determined to estimate the total pore volume and more importantly the connecting pores and the throat volumes. The absolute permeability are exclusively the properties of the porous media, which determines the ease of flow of fluid through the porous media. Rock petrography study was done by examining the thin sections under optical microscope, Scanning Electron Microscope (SEM) and X-ray Diffractometer (XRD). From these studies the mineral and clay content of the reservoir was characterized, which helps to study the feasibility of a CEOR in upper Assam basin. This petrography study provides two and three dimensional accurate description of minerals of reservoir rock and clay particles. The porous media is a sandstone with high porosity and low absolute permeability. The clays present are smectite, kaolinite and illite with a dominance of smectite and kaolinite, conforming to the swelling and disintegration.
Morphometric Analysis of Parvati Basin, NW Himalaya: A Remote Sensing and GIS Based Approach
Authors: Khan Imran , Bali Rameshwar , Agarwal K.K. , Kumar Dhirendra , Singh Saurabh K.
Published: February 2021

Morphometry is a quantitative approach of analysing linear, areal and relief parameters to understand the role of neotectonic activity in geomorphologic evolution of a river basin. In the present study multi-disciplinary integrated approach using morphometric parameters along with remote sensing and GIS technique have been applied for determining the quantitative parameters indicative of neotectonic activity in the Parvati basin, Higher Himalaya. The lineament pattern observed in the basin shows major trend in NE-SW followed by NW-SE and NNE-SSW directions. The basin is a 6th order drainage basin with dominating dendratic – trellis drainage pattern having very strong structural/tectonic control and is in its late youth stage of geomorphic development. Parvati basin shows coarse drainage density with fine texture suggesting more surface runoff and less infiltration in the area. The basin is highly elongated in shape tapering towards the south-west with high susceptibility to erosion with lower peak flow for longer duration. The above observations clearly indicate a tectonic and lithological control over the evolution of drainage pattern of Parvati basin.
Hydrogeochemical Processes Regulating the Groundwater Quality and its Suitability for Drinking and Irrigation Purpose in Parts of Coastal Sindhudurg District, Maharashtra
Authors: Naidu Suneetha , Gupta Gautam , Singh Rambabu , Tahama Khan , Erram Vinit C.
Published: February 2021

The hydrochemistry of groundwater samples from the northern part of coastal Sindhudurg district, Maharashtra, India, was studied with an aim to comprehend its suitability for domestic and irrigation use. Groundwater samples were collected from 66 dug wells distributed over the study area, during the month of November 2017. The results of the chemical analysis indicate that the groundwater is alkaline in nature and are mainly characterized by Ca+-Mg+2-HCO3–, Ca+-Mg+2-Cl– and Na+-Cl– facies. The molar ratios of Na+/Cl–>1, both Mg2+/Na+ and Ca2+/Na+ ratios <1, (Ca2+ + Mg2+)/ (SO42– + HCO3–) = 1 suggest that the rock-water interaction of silicates / schistose rocks (quartz, chlorite, amphibolites, schist etc.) and ion exchange reaction are the major controlling factors of groundwater chemistry. Lower molar ratios of Cl–/ HCO3–< 0.5, NO3-/Cl-<0.3 observed reflect freshwater regime. Three samples which are in proximity to the Arabian Sea, deduce the effect of secondary contributions (saline water and anthropogenic sources). In order to determine the probable sources of groundwater contamination, principal component analysis was also carried out. The first three principal components with eigen value 1 or more are responsible for 71.31 %, 12.38% and 8.32% of the total variance in the data set, indicating major role of groundwater-rock interaction and marginal saltwater intrusion effect in the study area. Groundwater quality index computed for drinking purpose indicate that about 96% of the water samples lie within the permissible limits stipulated by the World Health Organization and Bureau of Indian Standards, and fall under the good to excellent category, suggesting its suitability for drinking purpose in the area. Water quality index indicates that most of the water is of excellent to good quality for irrigation, except for a few coastal samples.
Fluoride Hazard and Risk Enumeration of Hard Rock Unconfined Aquifers in the Extended Part of Chhota Nagpur Gneissic Complex
Authors: Bera Biswajit , Bhattacharjee Sumana , Chamling Meelan , Ghosh Arijit , Sengupta Nairita
Published: February 2021

Fluoride (F−) is the most electronegative and reactive micro nutrient and has no colour, taste and smell. WHO (1984) has set a range of 0.6 – 1.2 mg/l in drinking water. It is very essential element for strong teeth and bones in human being but beyond permissible limit, it is very harmful for human health. A field based scientific study was conducted in the year 2017 and 2018 in the district of Purulia, an extended part of Chhota Nagpur gneissic complex of North Singbhum craton. A total of 619 water samples were collected from various affected and non-affected villages and the important parameters like pH and Fe were tested within 24 hours in the laboratory. Around 1513 households with 4348 male and 3456 female from 320 villages spread over 20 blocks have been extensively surveyed, applying stratified random and quota sampling techniques. Furthermore, Likert method is applied to understand the scenario of vulnerability along with application of remote sensing and GIS techniques to prepare the digital maps. Besides, empirical equations are also computed to determine the magnitude of fluoride hazard, vulnerability and risk. The fluoride risk study (R=H+V) reveals that Puncha and Purulia II are the very high and high fluoride risk prone zone out of 20 blocks of Purulia district. Although the Singbhum craton is moderately fluoride hazard region but due to large degree of vulnerability in the recent years it has drastically changed into a high or very high fluoride risk category.
Synthesis and characterization of ZnO nanoparticles using aqueous extract of Becium grandiflorum for antimicrobial activity and adsorption of methylene blue
Authors: Kahsay Mebrahtu Hagos
Published: February 2021

Nanotechnology is a recent field of modern research dealing with synthesis, strategy and manipulation of particle’s structure in size range of 1–100 nm. This study introduces one of the methods of synthesis of nanoparticles, i.e., green synthesis of ZnO NPs using aqueous leaf extract of Becium grandiflorum (AM: ‘Yedegamentisie’). The biomolecules of the plant extract (such as phenols, flavonoids, saponins, glycosides, steroids, tannins and alkaloids) were used as capping and reducing agent during synthesis of ZnO NPs. Response surface methodology coupled with Box-Behnken design (RSM-BBD) was used to optimize the synthesis of ZnO NPs and adsorption studies of the as-synthesized ZnO NPs. Then, ZnO NPs was characterized using different spectroscopic and microscopic instruments such as UV–Vis spectroscopy, FTIR, XRD and SEM–EDS to consider its purity, shape and crystallinity. UV–Vis analysis showed peaks in the range 305–312 nm due to synthesis of ZnO NPs. FTIR analysis showed the availability of different phytochemicals in the plant extract and synthesis of ZnO NPs at 490 cm−1. Powder XRD patterns confirmed formation of phase pure wurtzite structures of ZnO NPs. The synthesized ZnO NPs were used to remove MB dye from aqueous solution by acting as a photocatalyst and adsorbent as well as, it also showed antimicrobial activity against two gram positive (Staphylococcus epidermidis, Staphylococcus aureus) and three gram negative (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa) bacteria.
Australian Social Policy and the Human Services
Authors: Carson Ed , Kerr Lorraine
Published: February 2021

Social policy encompasses the study of social needs, policy development and administrative arrangements aimed at improving citizen wellbeing and redressing disadvantage. Australian Social Policy and the Human Services introduces readers to the mechanisms of policy development, implementation and evaluation. This third edition emphasises the complexity of practice, examining the links and gaps between policy development and implementation and encouraging readers to develop a critical approach to practice. The text now includes an overview of Australia's political system and has been expanded significantly to cover contemporary issues across several policy domains, including changes in labour market structure, homelessness, mental health and disability, child protection and family violence, education policy, Indigenous initiatives, conceptualisations of citizenship, and the rights of diverse groups and populations. Written in an engaging and accessible style, Australian Social Policy and the Human Services is an indispensable resource for students and practitioners alike.
Diagnosing Cross‐Scale Kinetic Energy Exchanges From Two Submesoscale Permitting Ocean Models
Authors: Ajayi Adekunle , Le Sommer Julien , Chassignet Eric P. , Molines Jean‐Marc , Xu Xiaobiao , Albert Aurelie , Dewar William
Published: February 2021

Fine‐scale motions (<100 km) contribute significantly to the exchanges and dissipation of kinetic energy in the upper ocean. However, knowledge of ocean kinetic energy at fine‐scales (in terms of density and transfers) is currently limited due to the lack of sufficient observational data sets at these scales. The sea‐surface height measurements of the upcoming Surface Water and Ocean Topography (SWOT) altimeter mission should provide information on kinetic energy exchanges in the upper ocean down to 10–15 km. Numerical ocean models, able to describe ocean dynamics down to ∼10 km, have been developed in anticipation of the SWOT mission. In this study, we use two state‐of‐the‐art, realistic, North Atlantic simulations, with horizontal resolutions ∼1.5 km, to investigate the distribution and exchanges of kinetic energy at fine‐scales in the open ocean. Our results show that the distribution of kinetic energy at fine‐scales approximately follows the predictions of quasigeostrophic dynamics in summertime but is somewhat consistent with submesoscale fronts‐dominated regimes in wintertime. The kinetic energy spectral fluxes are found to exhibit both inverse and forward cascade over the top 1,000 m, with a maximum inverse cascade close to the average energy‐containing scale. The forward cascade is confined to the ocean surface and shows a strong seasonality, both in magnitude and range of scales affected. Our analysis further indicates that high‐frequency motions (<1 day) play a key role in the forward cascade and that the estimates of the spectral fluxes based on geostrophic velocities fail to capture some quantitative aspects of kinetic energy exchanges across scales.
Comments on “Poststorm Thermospheric NO Overcooling?” by Mikhailov and Perrone (2020)
Authors: Lei Jiuhou , Wang Wenbin , Burns Alan G. , Zhang Shun‐Rong , Dang Tong
Published: February 2021

Recently Mikhailov and Perrone (2020, https://doi.org/10.1029/2019ja027122) proposed the mechanism of neutral atomic oxygen reduction, which is associated with the upper atmospheric circulation, to explain the reduction of total thermospheric mass density during the storm recovery phase. The authors further concluded arbitrarily that there is no need to introduce the storm‐time overcooling concept. However, their methodology is fundamentally flawed and their results and conclusions are incorrect. Instead, the overcooling scenario remains a viable concept in understanding thermospheric variations in the storm recovery phase.
Nitric Oxide Ion Density Profiles in Earth's Nightside High‐Latitude E and F Region Ionosphere
Authors: Ferdi Mohammed A. , Djebli Mourad
Published: February 2021

Transport effects on nitric oxide (NO) ion density, NO+, in the presence of suprathermal electrons in the nighttime high‐latitude E and F regions of Earth's ionosphere are investigated numerically. Our model includes ion drift induced by neutral winds for the NO+. Ionization rates are obtained using a numerical Boltzmann equation solver for electron transport. Ions densities are obtained from the IRI2016 model while horizontal winds are based on observations. It is found that the altitudes where our modeled peak NO+ densities occur are in good agreement with observations. By including the radiative transfer model, local minima in NO+ density (troughs) are found to be sensitive to electron impact considered previously in chemical models.
The Contribution of Currents, Sea‐Swell Waves, and Infragravity Waves to Suspended‐Sediment Transport Across a Coral Reef‐Lagoon System
Authors: Pomeroy Andrew W. M. , Storlazzi Curt D. , Rosenberger Kurt J. , Lowe Ryan J. , Hansen Jeff E. , Buckley Mark L.
Published: February 2021

Coral reefs generate substantial volumes of carbonate sediment, which is redistributed throughout the reef‐lagoon system. However, there is little understanding of the specific processes that transport this sediment produced on the outer portions of coral reefs throughout a reef‐lagoon system. Furthermore, the separate contributions of currents, sea‐swell waves, and infragravity waves to transport, which are all strongly influenced by the presence of a reef, is not fully understood. Here, we show that in reef‐lagoon systems most suspended sediment is transported close to the seabed and can, at times, be suspended higher in the water column during oscillatory flow transitions (i.e., near slack flow) at sea‐swell wave frequencies, and during the peak onshore oscillatory velocity phase at infragravity wave frequencies. While these wave frequencies contribute to the transport of suspended sediment offshore and onshore, respectively, the net flux is small. Mean currents are the primary transport mechanism and responsible for almost 2 orders of magnitude more suspended‐sediment flux than sea‐swell and infragravity waves. Whilst waves may not be the primary mechanism for the transport of sediment, our results suggest they are an important driver of sediment suspension from the seabed, as well as contributing to the partitioning of sediment grain sizes from the reef to the shoreline. As the ocean wave climate changes, sea level rises, and the composition of reef benthic communities change, the relative importance of mean currents, sea‐swell waves, and infragravity waves is likely to change, and this will affect how sediment is redistributed throughout reef‐lagoon systems.
Role of Extratropical Wintertime Cyclones in Regulating the Variations of Baffin Bay Sea Ice Export
Authors: Liang Yu , Bi Haibo , Wang Yunhe , Huang Haijun , Zhang Zehua , Huang Jue , Liu Yanxia
Published: February 2021

A cyclone is an intensive synoptic activity that occurs frequently over Baffin Bay. By modifying the large‐scale distribution pattern of sea level pressure, a passing cyclone can serve as an important regulator of sea ice outflow via the Davis Strait. We obtain a nearly 40‐year‐long record (1979/1980–2017/2018) of the sea ice area flux (SIAF) through the Davis Strait and Arctic cyclone activities in winter. A case study and statistical results indicate that the sea ice concentration and motion fields can be greatly altered by the occurrence of cyclones, thereby contributing to changes in sea ice export. Moreover, the effects of cyclones on sea ice export in Baffin Bay are dependent on the spatial distribution pattern of the storms. In terms of the cyclone center count and intensity, the key regions with significant impacts on sea ice export out of Baffin Bay are identified, one around Baffin Island (80°W–60°W, 60°N–70°N) and the other over the southern Labrador Peninsula (70°W–50°W, 40°N–60°N). A robust correlation exists between the winter‐accumulated SIAF via the Davis Strait and the average winter cyclone intensity (center count) in the critical regions with R = −0.57 (+0.49), affirming the vital role of cyclone activity in modulating the interannual variability of sea ice export in Baffin Bay.
Nutrient Balance and Use Efficiency in Agricultural Lands in the Vermelho River Watershed, Upper Pantanal, Brazil
Authors: Pacheco F. S. , Ometto J. P. H. B. , Gomes L. , Tôsto K. , Miranda M. , Loverde‐Oliveira S. , Pessi D. D. , Cox C.
Published: February 2021

Agricultural systems play a key role in achieving many of the Sustainable Development Goals, established by the United Nations, given the current challenge of producing enough food to feed a global population that is expected to reach 10 billion people by 2050. More efficient and sustainable use of nutrients in agriculture is an important step to increasing production while minimizing threats to natural ecosystems and resource depletion. In this study, we developed a system nutrient balance for nitrogen (N) and phosphorus (P) to evaluate nutrient use practices in cropping and grazing systems in the Vermelho River watershed (VRW), Upper Pantanal, Brazil, and investigated options to improve N and P use efficiency (NUE and PUE). Our results show P balance in cropping systems are positive while those in grazing systems tend to be negative. The positive values in cropping systems are due to both high P inputs from mineral fertilizers and high soil P‐sorbing capacities. The negative values in grazing systems are a result of the removal of animal products without replacing the nutrients. Most of the N inputs in the crops grown in this region come from biological nitrogen fixation. The NUE in cropping systems is about 0.95, which is higher than the upper critical value of the desirable range (0.6–0.9). Given the high NUE value and the risk of soil mining, improving cropping systems NUE by adjusting the inputs to replenish N outputs and avoid soil erosion in the VRW are of considerable interest.
Moon’s Largest Crater Holds Clues About Early Lunar Mantle
Authors: Thompson Elizabeth
Published: February 2021

An ancient impact splashed evidence of the Moon’s early mantle makeup onto its surface. Now researchers are piecing together models, maps, and samples to bring these mysteries to light.
Subduction May Recycle Less Water Than Thought
Authors: Stanley Sarah
Published: February 2021

A new analysis of seismic data from the Middle America Trench suggests that previous calculations have vastly overestimated the total amount of water transported to the mantle worldwide.
Superior reducing carbon dots from proanthocyanidin for free-radical scavenging and for cell imaging
Authors: Yang Dian , Li Li , Cao Lei , Zhang Yan , Ge Mingfeng , Yan Ruhong , Dong Wen-Fei
Published: February 2021

The presence of excessive ROS can cause much harm to the human body and can even cause diseases.
Ultrasound molecular imaging-guided tumor gene therapy through dual-targeted cationic microbubbles
Authors: Liu Yingying , Zhou Yuli , Xu Jinfeng , Luo Hui , Zhu Yao , Zeng Xinxin , Dong Fajin , Wei Zhanghong , Yan Fei , Zheng Hairong
Published: February 2021

A novel dual-targeted cationic microbubbles help to improve gene transfection efficiency.
A temperature-reduced method for the rapid growth of hybrid perovskite single crystals with primary alcohols
Authors: Höcker Julian , Brust Felix , Armer Melina , Dyakonov Vladimir
Published: February 2021

In this work, we present the simple and temperature-reduced reactive inverse temperature crystallisation (RITC) method to rapidly grow high-quality organic lead trihalide perovskite single crystals.
Continuous-flow formic acid production from the hydrogenation of CO2 without any base
Authors: Zhang Zhaofu , Liu Shuaishuai , Hou Minqiang , Yang Guangying , Han Buxing
Published: February 2021

Continuous-flow formic acid production from the hydrogenation of CO2 without any base, and the concentration of formic acid by electrodialysis was tested both offline and online.
Influence of hollow sphere surface heterogeneity and geometry of N-doped carbon on sensitive monitoring of acetaminophen in human fluids and pharmaceutical products
Authors: Emran Mohammed Y. , Talat Eslam , El-Safty Sherif A. , Shenashen Mohamed A. , Saad Eman M.
Published: February 2021

A sensitive and selective acetaminophen sensor assay was designed based on N-HCCS. The surface morphology, and composition of open hollow conjugated spheres of N-HCCS resulted in facile AC diffusion/loading and electrocatalytic oxidation.
MXene-encapsulated hollow Fe3O4 nanochains embedded in N-doped carbon nanofibers with dual electronic pathways as flexible anodes for high-performance Li-ion batteries
Authors: Guo Ying , Zhang Deyang , Yang Ya , Wang Yangbo , Bai Zuxue , Chu Paul K. , Luo Yongsong
Published: February 2021

The flexible Fe3O4@MXene/CNFs electrode can efficiently enhance the adsorption of Li+, and improve the electronic conductance and ion transfer rate. The nanochains-like Fe3O4@MXene/CNFs electrodes constitute distinctive dual electronic pathways.
Self-sintering liquid metal ink with LAPONITE® for flexible electronics
Authors: Wu Pengcheng , Zhou Luyu , Lv Shang , Fu Jianzhong , He Yong
Published: February 2021

A special liquid metal-LAPONITE® (LML) ink and the corresponding patterning strategy are proposed here for fabricating LM-based flexible and stretchable electronic devices.
Reaction of carbon oxides with an ethylene-bridged PH/B Lewis pair
Authors: Sun Qiu , Daniliuc Constantin G. , Kehr Gerald , Erker Gerhard
Published: February 2021

The ethylene-bridged frustrated Lewis pair, formed by hydroboration of the Mes*P(H)-vinyl phosphane with Piers' borane [HB(C6F5)2], reacted with the CO/ HB(C6F5)2pair and also with carbon dioxide.
Development of a novel colorimetric thermometer based on poly(N-vinylcaprolactam) with push–π–pull tricyanofuran hydrazone anion dye
Authors: Abdelrahman Meram S. , Khattab Tawfik A. , Kamel Samir
Published: February 2021

Thermochromic poly(N-vinylcaprolactam-co-tricyanofuran hydrazone) [poly(VC-co-TCFH)] gel labeled with a halochromic chromophore was developed using traditional free radical polymerization.
Constraining the population of isolated massive stars within the Central Molecular Zone
Authors: Clark J. S. , Patrick L. R. , Najarro F. , Evans C. J. , Lohr M.
Published: February 2021

Context. Many galaxies host pronounced circumnuclear starbursts, fuelled by infalling gas. Such activity is expected to drive the secular evolution of the nucleus and generate super winds which enrich the interstellar and intergalactic medium. Moreover, given the intense radiation fields and extreme gas and cosmic ray densities present within such regions, one might question whether star formation proceeds in a different manner to that occurring in more quiescent regions of the galactic disc, potentially leading to a dependence of the stellar initial mass function on the local environment.

Aims. To address the physics of circumnuclear starbursts, we are driven to observe the centre of our own Galaxy, which is the only example where individual stars may be resolved. Previous studies have revealed a rich population of very massive stars, found in three young massive clusters as well as being distributed, in apparent isolation, throughout the inner ∼500 pc of the Galaxy. In this paper we investigate the size and composition of the latter cohort in order to constrain its origin and role in the lifecycle of the Galactic Centre.

Methods. To accomplish this, we utilised the Very Large Telescope + K-band Multi-Object Spectrograph to obtain homogeneous, high signal-to-noise ratio observations of known and candidate massive stars suitable for spectral classification and quantitative analysis.

Results. We identified 17 new isolated massive stars and reclassified a further 19 known examples, leading to a total of at least 83 within the Galactic Centre. Due to the selection criteria employed, these were strongly biased towards stars with powerful stellar winds and/or extensive circumstellar envelopes; as such, we suspect the resultant census to be incomplete. No further stellar clusters, or their tidally stripped remnants, were identified, although an apparent overdensity of very young and massive stars is found to be coincident with the Sgr B1 star forming region.

Conclusions. Despite the limitations of the current dataset, the size of the cohort of outlying massive stars within the Galactic Centre is directly comparable to that of the known clusters and, assuming a comparable mass function, is expected to exceed this number. Combining both cluster and isolated populations yields ≳320 spectroscopically classified stars within the Galactic Centre that are sufficiently massive that they might be anticipated to undergo core collapse within the next ∼20 Myr. Given this is almost certainly a substantial underestimate of the true number, the population of massive stars associated with the Galactic Centre appears unprecedented within the Milky Way, and it appears unavoidable that they play a substantial role in the energetics and evolution of this region.
A study of the H I gas fractions of galaxies at z ∼ 1
Authors: Zhang Wei , Kauffmann Guinevere , Wang Jing , Chen Yanmei , Fu Jian , Wu Hong
Published: February 2021

Aims. Due to the fact that H I mass measurements are not available for large galaxy samples at high redshifts, we apply a photometric estimator of the H I-to-stellar mass ratio (MHI/M*), calibrated using a local Universe sample of galaxies, to a sample of galaxies at z ∼ 1 in the DEEP2 survey. We use these H I mass estimates to calculate H I mass functions (HIMFs) and cosmic H I mass densities (ΩHI) as well as to examine the correlation between star formation rates and H I gas content for galaxies at z ∼ 1.

Methods. We have estimated H I gas masses for ∼7000 galaxies in the DEEP2 survey with redshifts in the range 0.75 < z < 1.4 and stellar masses M* ≳ 1010 M⊙ using a combination of the rest-frame ultraviolet-optical colour (NUV − r) and stellar mass density (μ*) to estimate MHI/M*.

Results. It is found that the high-mass end of the high-z HIMF is quite similar to that of the local HIMF. The lower limit of ΩHI,limit = 2.1 × 10−4 h70−1, obtained by directly integrating the H I mass of galaxies with M* ≳ 1010 M⊙, confirms that massive star-forming galaxies do not dominate the neutral gas at z ∼ 1. We study the evolution of the H I-to-stellar mass ratio from z ∼ 1 to today and find a steeper relation between the H I gas mass fraction and stellar mass at higher redshifts. Specifically, galaxies with M* = 1011 M⊙ at z ∼ 1 are found to have 3−4 times higher neutral gas fractions than local galaxies, while the increase is as high as 4−12 times at M* = 1010 M⊙. The quantity MHI/SFR exhibits very large scatter, and the scatter increases from factors of 5−7 at z = 0 to factors close to 100 at z = 1. This implies that there is no relation between H I gas and star formation in high-redshift galaxies. The H I gas must be linked to cosmological gas accretion processes at high redshifts.
Probing core overshooting using subgiant asteroseismology: The case of KIC10273246
Authors: Noll A. , Deheuvels S. , Ballot J.
Published: February 2021

Context.The size of convective cores remains uncertain, despite their substantial influence on stellar evolution, and thus on stellar ages. The seismic modeling of young subgiants can be used to obtain indirect constraints on the core structure during main sequence, thanks to the high probing potential of mixed modes.

Aims.We selected the young subgiant KIC10273246, observed byKepler, based on its mixed-mode properties. We thoroughly modeled this star, with the aim of placing constraints on the size of its main-sequence convective core. A corollary goal of this study is to elaborate a modeling technique that is suitable for subgiants and can later be applied to a larger number of targets.

Methods.We first extracted the parameters of the oscillation modes of the star using the fullKeplerdata set. To overcome the challenges posed by the seismic modeling of subgiants, we propose a method that is specifically tailored to subgiants with mixed modes and uses nested optimization. We then applied this method to perform a detailed seismic modeling of KIC10273246.

Results.We obtain models that show good statistical agreements with the observations, both seismic and non-seismic. We show that including core overshooting in the models significantly improves the quality of the seismic fit, optimal models being found forαov = 0.15. Higher amounts of core overshooting strongly worsen the agreement with the observations and are thus firmly ruled out. We also find that having access to twog-dominated mixed modes in young subgiants allows us to place stronger constraints on the gradient of molecular weight in the core and on the central density.

Conclusions.This study confirms the high potential of young subgiants with mixed modes to investigate the size of main-sequence convective cores. It paves the way for a more general study including the subgiants observed withKepler, TESS, and eventually PLATO.
Effects of residual stress and fluid loading on vibrations of a micro-diaphragm on a free fluid surface
Authors: Ma Shujun
Published: February 2021

In this paper, we propose a straightforward theoretical model to examine free vibrations of circular diaphragms subjected to residual stress vibrating on a free fluid surface, which is infinite in the radial direction. An incompressible and inviscid fluid is assumed, and its movement is considered to be insignificant. The mode shapes and resonant frequencies of the diaphragm are determined by the Rayleigh–Ritz approach, taking fluid–diaphragm coupling and residual stress into consideration. We also establish a finite element model to demonstrate the accuracy of the numerical calculation. The analysis shows the residual stress and fluid loading influences on the mode shapes, the natural frequencies, the non-dimensional added virtual mass incremental factors, and the mass sensitivities of the diaphragms. The proposed framework will shed new light on the fundamental understanding of numerous applications involving resonating sensors in contact with the surrounding fluid in a broad sense.
Solution of two-electron Schrödinger equations using a residual minimization method and one-dimensional basis functions
Authors: Ur Rahman Faiz , Sarwono Yanoar Pribadi , Zhang Rui-Qin
Published: February 2021

Distinctive from conventional electronic structure methods, we solve the Schrödinger wave equations of the helium atom and its isoelectronic ions by employing one-dimensional basis functions to separate components. We use full two-electron six-dimensional operators and wavefunctions represented with real-space grids where the refinement of the latter is carried out using a residual minimization method. In contrast to the standard single-electron approach, the current approach results in exact treatment of repulsion energy and, hence, more accurate electron correlation within five centihartrees or better included, with moderate computational cost. A simple numerical convergence between the error to accurate results and the grid-spacing size is found. The obtained two-electron Schrödinger wavefunction that contains vast and elaborating information for the radial correlation function and common one-dimensional functions shows the electron correlation effect on one-electron distributions.
New charge-transfer states in blends of ZnPC with F8ZnPC
Authors: Graf Lukas , Ortstein Katrin , Doctor Louis P. , Naumann Marco , Beyer Jan , Heitmann Johannes , Leo Karl , Knupfer Martin
Published: February 2021

With the aim of pushing the knowledge and understanding on mixed films of organic semiconductors forward, blends of ZnPC and F8ZnPC in different ratios are manufactured. The films have a polycrystalline structure, as indicated by electron diffraction profiles and infrared-spectroscopy. Photoluminescence data show completely different spectra for the blends, compared to the pure materials, which can be ascribed to the suppressing of excimer formation and the appearance of a new charge-transfer excitation between the two different molecules in the blends. This new excitation can also be seen in optical absorption. Momentum dependent measurements of the electronic excitations by electron energy-loss spectroscopy confirm the localized character of the new charge-transfer excitation in the blends. Our experimental data help understand the important issue of donor/acceptor coupling in organic semiconductors.
Preparation of superhydrophobic paper with double-size silica particles modified by amino and epoxy groups
Authors: Jiang Shangjie , Zhou Shisheng , Du Bin , Luo Rubai
Published: February 2021

In this study, we composite coated silica nanoparticles with functional groups on paper to form a double-size surface roughness, then hexafluorobutyl methacrylate was polymerized with 3-trimethoxymethylsilyl propyl methacrylate (TSPM), a one-step method is used to prepare a hydrophobic polymer with low surface energy (PHFMA-co-TSPM), and the superhydrophobic surface was prepared by hydrophobic treatment of the paper with a low surface energy polymer. Further tests show that the superhydrophobic paper prepared by this method not only exhibits extremely strong hydrophobicity, but also has strong stability, transparency, and self-cleaning properties.
Anomalous vortex liquid in charge-ordered cuprate superconductors
Authors: Hsu Yu-Te , Berben Maarten , Čulo Matija , Adachi Seiji , Kondo Takeshi , Takeuchi Tsuneshiro , Wang Yue , Wiedmann Steffen , Hayden Stephen M. , Hussey Nigel E.
Published: February 2021

Significance

The magnetic-field scale at which superconducting vortices persist in underdoped cuprate superconductors has remained a controversial subject. Here we present an electrical transport study on three distinctly different cuprate families, at temperatures down to 0.32 K and magnetic fields up to 45 T. We reveal the presence of an anomalous vortex liquid state with a highly nonohmic resistivity in all three materials, irrespective of the level of disorder or structural details. The doping and field regime over which this anomalous vortex state persists suggests its occurrence is tied to the presence of long-range charge order under high magnetic field. Our results demonstrate that the intricate interplay between charge order and superconductivity can lead to an exotic vortex state.
Gene duplication at the
Fascicled ear1
locus controls the fate of inflorescence meristem cells in maize
Authors: Du Yanfang , Lunde China , Li Yunfu , Jackson David , Hake Sarah , Zhang Zuxin
Published: February 2021

Significance

The maize ear is unbranched and terminates in a single point. The ear and tassel inflorescences of
Fascicled ear
mutants fail to grow as a single point and instead are branched. This phenotype results from the misexpression of duplicated transcription factors, ZMM8 and DRL2. We hypothesize that these gene rearrangements create regulatory sequences that cause misexpression in early inflorescence meristems, thus activating a laminar program, ablating the meristem, and producing branches. This work demonstrates that
zmm8
and
drl2
must be restricted from the inflorescence meristem to maintain its terminal point, and conversely, a mechanism by which branching may be imposed. Manipulation of these genes can be used to alter plant architecture, potentially to improve agronomic traits.
Fighting monetary colonialism in francophone Africa: Samir Amin’s contribution
Authors: Sylla Ndongo Samba
Published: February 2021

This article discusses Samir Amin’s intellectual and activist contribution to the political economy of decolonisation in sub-Saharan Africa. It focuses on his fight from 1969 to 1975 for the monetary sovereignty of West African countries using the CFA franc, a colonial currency that survived independence. Amin was an advisor to Niger’s President Hamani Diori alongside whom he fought to end monetary colonialism. As an alternative to the CFA franc, Amin recommended an ambitious economic integration for the West Africa region based on mutually supportive national currencies. Although his proposal would meet opposition from France, Senegal and Côte d’Ivoire, his economic case against the CFA franc is still relevant. With regard to the ongoing protests against the CFA franc, it is important to recall a major teaching from Amin: although monetary autonomy is necessary for economic development in peripheral countries, without a delinking strategy its effects will be limited.
Improved anchor design for flat MEMS structure by suppressing deformation due to buried-oxide stress on silicon-on-insulator wafer
Authors: Fujiyoshi Motohiro , Ozaki Takashi , Omura Yoshiteru , Funabashi Hirofumi , Akashi Teruhisa , Nonomura Yutaka
Published: February 2021

Silicon-on-insulator (SOI) wafers are used in many micro-electromechanical system (MEMS) devices because of their stable mechanical properties. However, one of the disadvantages of using the SOI configuration is residual stress deformation; strong residual stresses in the buried-oxide layer deform the device and deteriorate its performance. This could prevent the development of high-precision sensors and actuators. In recent years, a new deformation mode caused by this residual stress has been reported, involving tilting of the suspended MEMS structure owing to local deformation of the anchor. However, methods to solve this problem have not yet been proposed. In this study, we propose a simple T-shaped support as a solution to the tilt deformation. We verified its effects by finite element analysis and experiments; the proposed structure was observed to successfully reduce the tip displacement of a SOI-based cantilever by one-fourth. In addition, we applied the proposed method to a parallel-plate accelerometer as a demonstration to confirm that the sensitivity variations of the device reduced from 10.8% to 6.8% using the proposed support structure. Thus, we believe that the proposed design can contribute to the development of extremely accurate MEMS sensors and optical devices.
Implementation of smartphone-based experimental exercises for physics courses at universities
Authors: Kaps A , Splith T , Stallmach F
Published: February 2021

A concept for undergraduate mechanics courses at universities is introduced where traditional pencil-paper based exercises are partially replaced by experimental exercises, in which smartphones are used as measurement devices. A detailed guidance for practical realization and implementation of these tasks formats into the course is presented. Three smartphone-based experimental exercises ‘The tilting smartphone’, ‘The oscillation balance’ and ‘Using the Smartphone in a Torsion Pendulum’ are presented. First empirical results with respect to the learning achievement indicate a mid size effect on the understanding of the physical concepts. Compared to the traditional pencil-paper based exercises, the students performance in the experimental exercises is slightly lower, although the motivation to solve these tasks is higher.
An Approach to Analyze Duality of Current-type DC-DC Circuit and Voltage-type DC-DC circuit based on Gyrator
Authors: Zheng Zhenhong , Ran Li
Published: February 2021

This paper proposes a method that can derive the current-type (C-T) DC-DC circuit topology from the voltage-type (V-T) DC-DC circuit topology by the duality of two-ports gyrator. In addition, the mathematical relationships between C-T DC-DC circuit and V-T DC-DC circuit parameters are established using the gyration resistance and the duty cycle of power switching device. Hence, C-T DC-DC parameters of the passive components, and the expressions of the mathematical relationships between the input and output, including the ripples of inductance current and capacitance voltage are obtained by analysing and calculating the V-T DC-DC circuit. Finally, the analysis results are verified by simulation in SIMULINK.
CAE-based classification method of electric power business
Authors: Ma Ruiheng , Xiang Min , Lei Rujie , Huang Chunmei
Published: February 2021

Aiming at the problem that abnormal data in the business classification of power data communication networks will reduce the business classification accuracy, a classification method based on convolutional autoencoder combined with lightGBM was proposed. First, the flow features of the electric power business were extracted through the convolutional autoencoder. Then, anomaly detection was realized according to the relationship between the reconstruction loss of the convolutional autoencoder and the set threshold. Finally, the electric power business was classified through the LightGBM classifier. The Moore data set used for simulation verification. The results show that the proposed method can effectively detect abnormalities, thereby improving the accuracy of the electric power business classification.
Research on DC Charger Interoperability Test for Electric Vehicles
Authors: Li Yulan , Wang Guangyan
Published: February 2021

DC charger is an important facility for electric vehicles to quickly replenish electric energy. Its operation safety, reliability and interoperability are of great significance for improving the popularity of charging facilities and the development of electric vehicles. Starting from the charging process of DC charger, this paper develops a set of DC charger interoperability testing device in combination with relevant testing specifications of DC charger, and carries out relevant tests on DC charger to verify the effectiveness of this set of equipment.
Power Grid Safety Assessment Based on an Improved Generative Adversarial Network
Authors: Aidong XU , Yunan ZHANG , Yixin JIANG
Published: February 2021

Critical clearing time (CCT) is one of the important indices for transient stability evaluation. From the data-driven perspective, the research on CCT prediction is troubled by changing models and insufficient samples, that is, the small sample characteristics of the target system may be submerged by the large sample characteristics of the source system. In this paper, a prediction method of CCT based on improved generative adversarial network (WGAN) is put forward to solve this problem, and the network structure of WGAN is redesigned. This method is suitable for the transition phase of power grid when the operation mode changes. Through the unsupervised training of WGAN, the neural network will automatically learn the complex relationship between the small sample data of the target system, so that the generator can produce small sample data with high precision. Then the CCT prediction model was built on the expanded balanced dataset. Results validate that the method can effectively learn the distribution law of samples, improve the CCT prediction ability, and has the advantage of precision in the transition phase of power grid with insufficient samples.
Vehicle Ethernet Flow Estimation Using Intelligent Methods
Authors: Hu ZhengWei , Li Hui , Li Yang , Li XueZhen , Li Peng
Published: February 2021

For modern vehicle communications systems, it is vital to utilize advanced networks such as Ethernet to enhance the network speed, improve the service, and avoid the congestion. To this end, it is necessary to develop a hardware platform as well as a flow estimation scheme for system optimization. In this paper, we formulate the vehicle Ethernet platform using Duagon cards under the standard of IEC 61375. Then, we propose three intelligent methods for vehicle flow estimation, i.e., the support vector machine (SVM), the back propagation (BP) neural network, and recurrent neural network (RNN) using improved back-propagation through time (BPTT). Comparative studies are performed to validate the proposed scheme. The results provide technical support for statistical characters analysis and high speed monitoring of modern vehicles.
PMSM double loop predictive control based on Luenberger observer
Authors: Chen Dongdong , Li Zongwei , Chen Ying , Lei Hongdan , Zhu Hongguan , Zeng Qiyi
Published: February 2021

Predictive control strategy is applied to permanent magnet synchronous motor (PMSM) control system, it can achieve fast dynamic response and high-precision tracking control, but depending on the mathematical model of the (PMSM), the load disturbance will affect the control performance of system. Therefore, a control method based on the combination of Luenberger observer and predictive control is proposed to construct a double closed-loop predictive control system. Through the load disturbance estimated by the Luenberger observer, the torque current compensation produced is used as the feedforward compensation of the speed loop to achieve disturbance suppression. The simulation results under Simulink environment show that this method can improve the dynamic response performance and steady-state accuracy of the control system, and greatly improve the robustness.
Research on Control Strategy of Three-Phase Inverter Based on Fractional Calculus
Authors: kai YAN , chaojun WU , zhang LIU , qi ZHANG
Published: February 2021

Three-level inverters has widely used in Medium pressure due to its advantages of low total harmonics, low voltage resistance of power switch tubes and low switching losses. In order to further improve the output voltage waveform quality and optimal control effect of the Three-level inverter, this paper introduces fractional calculus in the control method of the three-level inverter circuit. First, designed a control strategy for the fractional voltage outer loop. Secondly, the use of vector representation simplifies the parameter tuning of fractional-order controller, the optimization process of the parameters of the fractional order PIλ and integer-order PI is completed by utilizing the ITAE rules. At the same time, the Oustaloup approximation method realizes the fractional integral operator in the controller, thereby achieving the purpose of improving the output voltage of the system. For three-level inverter circuit model, comparative analysis of the control effects of the fractional-order PIλ and integer-order PI. Finally, simulation results show that fractional-order PIλ controllers have excellent flexibility, robustness.