bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the Key Aroma Compounds of Three Kinds of Chinese Representative Black Tea and Elucidation of the Perceptual Interactions of Methyl Salicylate and Floral Odorants
Authors: Niu Yunwei , Ma Yiwei , Xiao Zuobing , Zhu Jiancai , Xiong Wen , Chen Feng
Published: March 2022

Jinjunmei (JJM), Keemun (KM), and Dianhong (DH) are the representative black teas in China, and they have always been favored by consumers. In this study, we aim to obtain the aroma characteristic information of volatile components in black tea samples through headspace solid-phase microextraction (HS-SPME), solvent-assisted flavor evaporation (SAFE), and gas chromatography-mass spectrometry combined with gas chromatography-olfactometry technology. The results showed that 70 compounds including α-methylbenzyl alcohol (isomer of β-phenylethanol) were identified as odorants. Among them, 39 compounds such as linalool and geraniol showed a high degree of aroma contribution. Furthermore, the Feller’s additive model was used to explore the perceptual interactions among the methyl salicylate and the floral compounds (10 groups): five groups of binary compounds showed masking effect after mixing, one group showed additive effect, and four groups showed synergistic effect. The ratio (R) was compared with the aroma index (n) of Steven’s law, which found a high-fitness exponential relationship. The results of this study help to provide additional and new theoretical guidance for improving the aroma quality of black tea.
Jusanin, a New Flavonoid from Artemisia commutata with an In Silico Inhibitory Potential against the SARS-CoV-2 Main Protease
Authors: Suleimen Yerlan M. , Jose Rani A. , Suleimen Raigul N. , Arenz Christoph , Ishmuratova Margarita Y. , Toppet Suzanne , Dehaen Wim , Alsfouk Bshra A. , Elkaeed Eslam B. , Eissa Ibrahim H. , Metwaly Ahmed M.
Published: March 2022

A new flavonoid, Jusanin, (1) has been isolated from the aerial parts of Artemisia commutata. The chemical structure of Jusanin has been elucidated using 1D, 2D NMR, and HR-Ms spectroscopic methods to be 5,2′,4′-trihydroxy-6,7,5′-trimethoxyflavone. Being new in nature, the inhibition potential of 1 has been estimated against SARS-CoV-2 using different in silico techniques. Firstly, molecular similarity and fingerprint studies have been conducted for Jusanin against co-crystallized ligands of eight different SARS-CoV-2 essential proteins. The studies indicated the similarity between 1 and X77, the co-crystallized ligand SARS-CoV-2 main protease (PDB ID: 6W63). To confirm the obtained results, a DFT study was carried out and indicated the similarity of (total energy, HOMO, LUMO, gap energy, and dipole moment) between 1 and X77. Accordingly, molecular docking studies of 1 against the target enzyme have been achieved and showed that 1 bonded correctly in the protein’s active site with a binding energy of −19.54 Kcal/mol. Additionally, in silico ADMET in addition to the toxicity evaluation of Jusanin against seven models have been preceded and indicated the general safety and the likeness of Jusanin to be a drug. Finally, molecular dynamics simulation studies were applied to investigate the dynamic behavior of the Mpro-Jusanin complex and confirmed the correct binding at 100 ns. In addition to 1, three other metabolites have been isolated and identified to be сapillartemisin A (2), methyl-3-[S-hydroxyprenyl]-cumarate (3), and β-sitosterol (4).
Application of New Energy Thermochromic Composite Thermosensitive Materials of Smart Windows in Recent Years
Authors: Feng Yu-Qin , Lv Mei-Ling , Yang Ming , Ma Wen-Xia , Zhang Gang , Yu Yun-Zi , Wu Ya-Qi , Li Hai-Bo , Liu De-Zheng , Yang Yong-Sheng
Published: March 2022

Thermochromic smart windows technology can intelligently regulate indoor solar radiation by changing indoor light transmittance in response to thermal stimulation, thus reducing energy consumption of the building. In recent years, with the development of new energy-saving materials and the combination with practical technology, energy-saving smart windows technology has received more and more attention from scientific research. Based on the summary of thermochromic smart windows by Yi Long research groups, this review described the applications of thermal responsive organic materials in smart windows, including poly(N-isopropylacrylamide) (PNIPAm) hydrogels, hydroxypropyl cellulose (HPC) hydrogels, ionic liquids and liquid crystals. Besides, the mechanism of various organic materials and the properties of functional materials were also introduced. Finally, opportunities and challenges relating to thermochromic smart windows and prospects for future development are discussed.
Recent Advances in Theoretical Development of Thermal Atomic Layer Deposition: A Review
Authors: Shahmohammadi Mina , Mukherjee Rajib , Sukotjo Cortino , Diwekar Urmila , Takoudis Christos
Published: March 2022

Atomic layer deposition (ALD) is a vapor-phase deposition technique that has attracted increasing attention from both experimentalists and theoreticians in the last few decades. ALD is well-known to produce conformal, uniform, and pinhole-free thin films across the surface of substrates. Due to these advantages, ALD has found many engineering and biomedical applications. However, drawbacks of ALD should be considered. For example, the reaction mechanisms cannot be thoroughly understood through experiments. Moreover, ALD conditions such as materials, pulse and purge durations, and temperature should be optimized for every experiment. It is practically impossible to perform many experiments to find materials and deposition conditions that achieve a thin film with desired applications. Additionally, only existing materials can be tested experimentally, which are often expensive and hazardous, and their use should be minimized. To overcome ALD limitations, theoretical methods are beneficial and essential complements to experimental data. Recently, theoretical approaches have been reported to model, predict, and optimize different ALD aspects, such as materials, mechanisms, and deposition characteristics. Those methods can be validated using a different theoretical approach or a few knowledge-based experiments. This review focuses on recent computational advances in thermal ALD and discusses how theoretical methods can make experiments more efficient.
Strain Engineering: A Pathway for Tunable Functionalities of Perovskite Metal Oxide Films
Authors: Dhole Samyak , Chen Aiping , Nie Wanyi , Park Baeho , Jia Quanxi
Published: March 2022

Perovskite offers a framework that boasts various functionalities and physical properties of interest such as ferroelectricity, magnetic orderings, multiferroicity, superconductivity, semiconductor, and optoelectronic properties owing to their rich compositional diversity. These properties are also uniquely tied to their crystal distortion which is directly affected by lattice strain. Therefore, many important properties of perovskite can be further tuned through strain engineering which can be accomplished by chemical doping or simply element substitution, interface engineering in epitaxial thin films, and special architectures such as nanocomposites. In this review, we focus on and highlight the structure–property relationships of perovskite metal oxide films and elucidate the principles to manipulate the functionalities through different modalities of strain engineering approaches.
Gut Microbiota Modulation of Moderate Undernutrition in Infants through Gummy Lactobacillus plantarum Dad-13 Consumption: A Randomized Double-Blind Controlled Trial
Authors: Kamil Rafli Zulfa , Murdiati Agnes , Juffrie Mohammad , Rahayu Endang Sutriswati
Published: March 2022

Undernutrition is associated with gut microbiota unbalance, and probiotics are believed to restore it and improve gut integrity. A randomized double-blind controlled trial was conducted to evaluate the efficacy of gummy L. plantarum Dad-13 (108−9 CFU/3 g) to prevent the progression of severe undernutrition. Two groups of moderate undernutrition infants were involved in this study, namely the placebo (n = 15) and probiotics (n = 15) groups, and were required to consume the product for 50 days. 16S rRNA sequencing and qPCR were used for gut microbiota analysis, and gas chromatography was used to analyze Short-Chain Fatty Acid (SCFA). The daily food intake of both groups was recorded using food records. Our results revealed that the probiotic group had better improvements regarding the anthropometry and nutritional status. In addition, L. plantarum Dad-13 modulated the butyric acid-producing bacteria to increase and inhibit the growth of Enterobacteriaceae. This gut modulation was associated with the increment in SCFA, especially total SCFA, propionic, and butyric acid. The number of L. plantarum was increased after the probiotic intervention. However, L. plantarum Dad-13 was not able to change the alpha and beta diversity. Therefore, L. plantarum Dad-13 has been proven to promote the growth of beneficial bacteria.
On the Mechanism of the Synthesis of Nitrofunctionalised Δ2-Pyrazolines via [3+2] Cycloaddition Reactions between α-EWG-Activated Nitroethenes and Nitrylimine TAC Systems
Authors: Fryźlewicz Agnieszka , Olszewska Aleksandra , Zawadzińska Karolina , Woliński Przemysław , Kula Karolina , Kącka-Zych Agnieszka , Łapczuk-Krygier Agnieszka , Jasiński Radomir
Published: March 2022

We investigated the reactivity of different substituted nitrylimine-type three atom components (TACs) in [3+2] cycloaddition (32CAs) reactions with electrophilically activated nitroethenes within molecular electron density theory (MEDT). In parallel research, the molecular mechanism of the considered transformation was examined through analysis of all possible reaction channels and full optimization of all critical structures. In particular, the existence of zwitterionic intermediates on reaction paths was verified. On the basis of the bonding evolution theory (BET), the mechanism of the 32CA reaction between C,N-diphenylnitrylimine and (E)-2-phenyl-1-cyano-1-nitroethene should be treated as a one-step two-stage mechanism.
Beyond CC398: Characterisation of Other Tetracycline and Methicillin-Resistant Staphylococcus aureus Genetic Lineages Circulating in Spanish Hospitals
Authors: Ceballos Sara , Lozano Carmen , Aspiroz Carmen , Ruiz-Ripa Laura , Eguizábal Paula , Campaña-Burguet Allelen , Cercenado Emilia , López-Calleja Ana , Castillo Javier , Azcona-Gutiérrez Jose , Torres Luis , Calvo Jorge , Martin Carmen , Navarro María , Zarazaga Myriam , Torres Carmen ,   the Study Group of Clinical LA-MRSA
Published: March 2022

Tetracycline resistance (TetR) has been evidenced as a good phenotypic marker for detection of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) isolates of the clonal complex CC398. The aim of this study was to characterise a collection of 95 TetR-MRSA isolates, not belonging to the lineage CC398, that were obtained in a previous multicentre study, to detect other MRSA clonal complexes that could be associated with this phenotypic TetR marker. The TetR-MRSA isolates were recovered from 20 Spanish hospitals during 2016 and they were characterised to determine their antimicrobial resistance and virulence phenotypes/genotypes as well as the presence of the immune evasion cluster (IEC). A high proportion of isolates belonging to the CC1 lineage (46%) were observed, as well as to the CC5, CC8 and CC45 lineages (11% each one). Thirty-two different spa-types were identified, being predominantly CC1-t127 (40%) and CC45-t1081 (11%). The IEC system (with the gene scn as marker) was present in 73% of isolates and 16% produced the Panton Valentine leucocidin (PVL). A high proportion of MRSA-CC1 isolates were scn-negative (38.6%) and 52.9% of them were blaZ-negative. A multidrug resistance (MDR) phenotype was identified in 86% of MRSA isolates. The knowledge of other TetR-MRSA genetic lineages, in addition to CC398, is highly relevant, since most of them were MDR and some of them presented important virulence factors. Strains potentially associated with livestock (as the subpopulation CC1-t127-scn-negative) or with humans (as the CC45 lineage or the subpopulation CC1-scn-positive) have been found in this study. The use of tetracycline-resistance for detection, not only of CC398 but also of other LA-MRSA lineages should be tracked in the future.
Repurposing of Ciclopirox to Overcome the Limitations of Zidovudine (Azidothymidine) against Multidrug-Resistant Gram-Negative Bacteria
Authors: Cho Hyejin , Kim Kwang-sun
Published: March 2022

Multidrug-resistant (MDR) Gram-negative bacteria are the top-priority pathogens to be eradicated. Drug repurposing (e.g., the use of non-antibiotics to treat bacterial infections) may be helpful to overcome the limitations of current antibiotics. Zidovudine (azidothymidine, AZT), a licensed oral antiviral agent, is a leading repurposed drug against MDR Gram-negative bacterial infections. However, the rapid emergence of bacterial resistance due to long-term exposure, overuse, or misuse limits its application, making it necessary to develop new alternatives. In this study, we investigated the efficacy of ciclopirox (CPX) as an alternative to AZT. The minimum inhibitory concentrations of AZT and CPX against MDR Gram-negative bacteria were determined; CPX appeared more active against β-lactamase-producing Escherichia coli, whereas AZT displayed no selectivity for any antibiotic-resistant strain. Motility assays revealed that β-lactamase-producing Escherichia coli strains were less motile in nature and more strongly affected by CPX than a parental strain. Resistance against CPX was not observed in E. coli even after 25 days of growth, whereas AZT resistance was observed in less than 2 days. Moreover, CPX effectively killed AZT-resistant strains with different resistance mechanisms. Our findings indicate that CPX may be utilized as an alternative or supplement to AZT-based medications to treat opportunistic Gram-negative bacterial infections.
Seasonal Changes in the Plant Growth-Inhibitory Effects of Rosemary Leaves on Lettuce Seedlings
Authors: Appiah Kwame Sarpong , Omari Richard Ansong , Onwona-Agyeman Siaw , Amoatey Christiana Adukwei , Ofosu-Anim John , Smaoui Abderrazak , Arfa Abdelkarim Ben , Suzuki Yoko , Oikawa Yosei , Okazaki Shin , Katsura Keisuke , Isoda Hiroko , Kawada Kiyokazu , Fujii Yoshiharu
Published: March 2022

Plant biodiversity has been studied to explore allelopathic species for the sustainable management of weeds to reduce the reliance on synthetic herbicides. Rosemary (Rosmarinus officinalis L., syn Salvia rosmarinus Spenn.), was found to have plant growth-inhibitory effects, and carnosic acid was reported as an allelochemical in the plant. In this study, the effects of seasonal variation (2011–2012) on the carnosic acid concentration and phytotoxicity of rosemary leaves from two locations in Tunisia (Fahs and Matmata) were investigated. The carnosic acid concentration in rosemary leaves was determined by HPLC, and lettuce (Lactuca sativa L.) was used as the receptor plant in the phytotoxicity bioassay. The highest carnosic acid concentration was found in rosemary samples collected in June 2011, which also had the highest inhibitory activity. Furthermore, a significant inverse correlation (r = −0.529; p < 0.01) was found between the inhibitory activity on lettuce hypocotyl and the carnosic acid concentration in rosemary leaves. Both temperature and elevation had a significant positive correlation with carnosic acid concentration, while rainfall showed a negative correlation. The results showed that the inhibitory effects of rosemary leaf samples collected in summer was highest due to their high carnosic acid concentration. The phytotoxicity of rosemary needs to be studied over time to determine if it varies by season under field conditions.
Automated Instrument for the Deposition of Thin Films Using Successive Ionic Layer Adsorption and Reaction
Authors: Woo-García Rosa M. , Rodríguez-Ibarra Isaac , Osorio-de-la-Rosa Edith , Guarneros-Aguilar Cesia , Caballero-Briones Felipe , Agustín-Serrano Ricardo , Herrera-May Agustín L. , López-Huerta Francisco
Published: March 2022

The development and improvement of thin film deposition techniques is an important research topic to obtain new materials at submicro and nano scale with high homogeneity and thickness control. Here, we designed and built an automated device for the deposition of binary or ternary compound films using Successive Ionic Layer Adsorption and Reaction (SILAR). The instrument is integrated by three different systems. The first system consists of a mobile platform of two degrees of freedom. The second part has an 8-bit microcontroller used to adjust the velocities along the horizontal and vertical axes. The third, the control system, uses a mobile app that can be implemented in smart devices, developed in free code software for programming and monitoring the main deposition parameters of the SILAR device such as the number of cycles, the immersion and emersion velocities, the residence time at each step, and the number of reactors. The performance of our instrument was verified through the deposition of PbS films, varying the number of deposition cycles to study the variations in the film thickness and structure, and assessed by profilometry, Raman spectroscopy, X-ray diffraction and atomic force microscopy. The system demonstrated is useful to obtain crystalline films with controllable thicknesses.
1-D Modeling of Two Phase Flow Process in Concentric Annular Heat Pipe and Experimental Investigation
Authors: Lee Ji-Su , Ahn Jae-Hyun , Chae Heui-Il , Lee Hi-Chan , Rhi Seok-Ho
Published: March 2022

As the heat dissipation of smart devices increases, cutting-edge cooling solutions are becoming increasingly important. The heat pipe is an efficient device that boosts heat transfer and is recommended to reduce thermal management power. In this study, a concentric annular heat pipe (CAHP) with distilled water as a working fluid is proposed to enhance heat transfer, and experiments and one-dimensional analysis were carried out to predict thermal characteristics and evaluate performance. The CAHP was 90 mm in length, 62 mm in inner diameter, 70 mm in outer diameter, and 0.4 mm in thickness. At the outer surface of the internal CAHP, a two-layer screen mesh wick (500 mesh, Stainless Steel 304) that is 0.34 mm in layer thickness was installed. A ceramic heater (20 mm × 20 mm) was attached to the middle of the outer surface, and the hollow region with 48 fins was cooled by an electric fan. The experiment was carried out with variations in the heat load, the filling ratio of the working fluid, the pitch angle, the roll angle, and the airflow speed, and the one-dimensional analysis was modeled by AMESIM. The experimental results showed that the best thermal resistance of the CAHP was 3.74 °C/W with a supplied heat of 20 W, a pitch angle of −15°, and a Vair of 3 m/s. In addition, the CAHP’s 1-D simulation model using AMESIM was verified through the experimental results. However, although the modeling results according to the inclination angle could not be reflected due to the difficulty of implementing multiple orientation structures in the one-dimensional simulation model, the simulation results were found to be almost consistent with the experimental results. Case studies were conducted to understand the various characteristics of the CAHP using the model, and the optimal volume fraction, the porosity, and the number of layers of the wicks were determined to be 10, 0.345, and 2, respectively.
Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications
Authors: Bié Joaquim , Sepodes Bruno , Fernandes Pedro C. B. , Ribeiro Maria H. L.
Published: March 2022

Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability.
From an Understanding to a Securitizing Discourse: The British Left’s Encounter with the Emergence of Political Islam, 1978–2001
Authors: Shabana Ihab
Published: March 2022

The outburst of The Iranian Revolution in 1978 generated fear and hope at the same time for several political forces across the West and the East. The emergence of Islam as a political force came as a surprise across all political spectrums in Europe, even though religion was already at the time becoming a determining variable in the field of international relations. The echoes of The Iranian Revolution precipitated even further the making of several organizations of political Islam in the Middle East, forging transnational identities. Through primary and secondary sources drawn from mainly British leftist organizations, this study aims at examining the responses of the British Left towards Islamic revivalism. Thus, this article gives an historical outline of the intellectual production and the strategies of interpretation adopted by the British Left during the period of 1978–2001, by exploring the main historical events that involved (political) Islam, such as The Iranian Revolution, the Lebanese civil war, the Palestinian Intifada and The Algerian Civil War. The main argument postulated is that interpretation trajectories by the British Left were highly dependent on ideological and geostrategic lineages and respective synchronic political alliances, resulting in putting the centre of gravity sometimes on Islamic activism’s regressive nature and sometimes on its anti-imperialist perspectives.
International Relations by Proxy? The Kremlin and the Russian Orthodox Church
Authors: Soroka George
Published: March 2022

Russian officials and the Moscow Patriarchate have worked together in recent years to promote a socially conservative policy agenda, both domestically and beyond the Russian Federation’s borders. Examining official documents and the statements of key leaders, this article evaluates the development and nature of contemporary church–state relations as they pertain to international relations. The picture that emerges is one of pragmatic partnering, with the state increasingly inclining towards normative positions long espoused by the Church in an effort to shift its foreign policy in a direction that stresses civilizational differentiation and positions Russia as the protector of Christians and “traditional values” around the globe. Underlying this shift in orientation on the part of the Kremlin is a neorealist perspective (though one increasingly expressed through ideational rhetoric) that envisions Russia as not just having a privileged regional sphere of influence but becoming a major player in a polycentric world. As a means of legitimating these objectives, the Church has proven an ideal partner; however, it would be a mistake to simply regard the latter institution as an arm of the state, given that it has its own objectives and motivations relative to the wider world, and these at times conflict with those of the Kremlin.
An Attempt at a Theoretical Explanation of Violent Islamist Radicalization in Spain
Authors: García Magariño Sergio , Jiménez-Ramos María
Published: March 2022

This paper is the first in a series of papers that aim to address Islamist violent radicalization from different angles: the nature of violent radicalization in the context of Spain; a comparison between European, North American, and Indian violent radicalization; the need to refine territorial radicalization indexes within the context of preventing violent radicalization and the relation between Islamist violent radicalization; and other forms of violent radicalization in Europe. This series of articles builds upon the general theoretical framework established by the author in two previous works. These works are framed under the known conception of three layers of micro, meso, and macro factors contributing to violent radicalization processes. The paper starts by defining Islamist violent radicalization. Then, it explores different theoretical explanations, and finally, it proposes an explanatory hypothesis that is tested against, on the one hand, data proceeding from different institutional sources in Spain and, on the other, some initial conversations to Spanish security officials and people who were radicalized in the past and regretted it or lived very close to others that did it. In further articles, these preliminary conversations will become life stories and in-depth interviews.
Monitoring Irrigation Events and Crop Dynamics Using Sentinel-1 and Sentinel-2 Time Series
Authors: Ma Chunfeng , Johansen Kasper , McCabe Matthew F.
Published: March 2022

Capturing and identifying field-based agricultural activities, such as the start, duration and end of irrigation, together with crop sowing/germination, growing period and time of harvest, offer informative metrics that can assist in precision agricultural activities in addition to broader water and food security monitoring efforts. While optically based band-ratios, such as the normalized difference vegetation index (NDVI) and normalized difference water index (NDWI), have been used as descriptors for monitoring crop dynamics, data are not always available due to the influence of clouds and other atmospheric effects on optical sensors. Satellite-based microwave systems, such as the synthetic aperture radar (SAR), offer an all-weather advantage in monitoring soil and crop conditions. In this paper, we leverage the relative strengths of both optical- and microwave-based approaches by combining high resolution Sentinel-1 SAR and Sentinel-2 optical imagery to monitor irrigation events and crop dynamics in a dryland agricultural landscape. A microwave backscatter model was used to analyze the responses of simulated backscatters to soil moisture, NDVI and NDWI (both are correlated with vegetation water content and can be regarded as vegetation descriptors), allowing an empirical relationship between these two platforms. A correlation analysis was also performed using Sentinel-1 SAR and Sentinel-2 optical data over crops of maize, alfalfa, carrot and Rhodes grass in Al Kharj farm of Saudi Arabia to identify an appropriate SAR-based vegetation descriptor. The results illustrate the relationship between SAR and both NDVI and NDWI and demonstrated the relationship between the cross-polarization ratio (VH/VV) and the two optical indices. We explore the capacity of this multi-platform and multi-sensor approach to inform on the spatio-temporal dynamics of a range of agricultural activities, which can be used to facilitate field-based management decisions.
Voids Filling of DEM with Multiattention Generative Adversarial Network Model
Authors: Zhou Guoqing , Song Bo , Liang Peng , Xu Jiasheng , Yue Tao
Published: March 2022

The digital elevation model (DEM) acquired through photogrammetry or LiDAR usually exposes voids due to phenomena such as instrumentation artifact, ground occlusion, etc. For this reason, this paper proposes a multiattention generative adversarial network model to fill the voids. In this model, a multiscale feature fusion generation network is proposed to initially fill the voids, and then a multiattention filling network is proposed to recover the detailed features of the terrain surrounding the void area, and the channel-spatial cropping attention mechanism module is proposed as an enhancement of the network. Spectral normalization is added to each convolution layer in the discriminator network. Finally, the training of the model by a combined loss function, including reconstruction loss and adversarial loss, is optimized. Three groups of experiments with four different types of terrains, hillsides, valleys, ridges and hills, are conducted for validation of the proposed model. The experimental results show that (1) the structural similarity surrounding terrestrial voids in the three types of terrains (i.e., hillside, valley, and ridge) can reach 80–90%, which implies that the DEM accuracy can be improved by at least 10% relative to the traditional interpolation methods (i.e., Kriging, IDW, and Spline), and can reach 57.4%, while other deep learning models (i.e., CE, GL and CR) only reach 43.2%, 17.1% and 11.4% in the hilly areas, respectively. Therefore, it can be concluded that the structural similarity surrounding the terrestrial voids filled using the model proposed in this paper can reach 60–90% upon the types of terrain, such as hillside, valley, ridge, and hill.
Rheology of the Northern Tibetan Plateau Lithosphere Inferred from the Post-Seismic Deformation Resulting from the 2001 Mw 7.8 Kokoxili Earthquake
Authors: Lv Xiaoran , Shao Yun
Published: March 2022

Time-series observations from Sentinel-1 A/B InSAR spanning November 2014 to July 2021 were used to study the late post-seismic deformation velocity field arising from the Kokoxili earthquake. The deformation velocity caused by the interseismic slip along the major active faults in Tibet was first simulated. Comparing the simulated deformation velocity with the observed one, the maximum ratio of the simulated deformation velocity to the observed one was found to be 42%, indicating continuity in the viscoelastic relaxation caused by the 2001 Kokoxili earthquake. Subsequently, the rheological structure of the Kokoxili region was explored using a mixed model comprising the viscoelastic relaxation mechanism and the buried elastic dislocation model. The best estimated viscosities for the lower crust and upper mantle were ηlc=1−0.44+0.78×1019 Pas and ηum=1+0+0.78×1020 Pas, respectively. The results obtained in this study were compared with those of previous studies that used the early post-seismic displacement ranging from 0 to 6.5 years following the earthquake. The obtained value was largely the same as the previously estimated steady-state viscosity, which means that the viscosities of the viscoelastic layer beneath the Kokoxili regions have almost reached their stable state. Furthermore, the effective lower crustal viscosity of the Kokoxili region exhibited a logarithmic trend with time.
An Interannual Transfer Learning Approach for Crop Classification in the Hetao Irrigation District, China
Authors: Hu Yueran , Zeng Hongwei , Tian Fuyou , Zhang Miao , Wu Bingfang , Gilliams Sven , Li Sen , Li Yuanchao , Lu Yuming , Yang Honghai
Published: March 2022

Crop type classification is critical for crop production estimation and optimal water allocation. Crop type data are challenging to generate if crop reference data are lacking, especially for target years with reference data missed in collection. Is it possible to transfer a trained crop type classification model to retrace the historical spatial distribution of crop types? Taking the Hetao Irrigation District (HID) in China as the study area, this study first designed a 10 m crop type classification framework based on the Google Earth Engine (GEE) for crop type mapping in the current season. Then, its interannual transferability to accurately retrace historical crop distributions was tested. The framework used Sentinel-1/2 data as the satellite data source, combined percentile, and monthly composite approaches to generate classification metrics and employed a random forest classifier with 300 trees for crop classification. Based on the proposed framework, this study first developed a 10 m crop type map of the HID for 2020 with an overall accuracy (OA) of 0.89 and then obtained a 10 m crop type map of the HID for 2019 with an OA of 0.92 by transferring the trained model for 2020 without crop reference samples. The results indicated that the designed framework could effectively identify HID crop types and have good transferability to obtain historical crop type data with acceptable accuracy. Our results found that SWIR1, Green, and Red Edge2 were the top three reflectance bands for crop classification. The land surface water index (LSWI), normalized difference water index (NDWI), and enhanced vegetation index (EVI) were the top three vegetation indices for crop classification. April to August was the most suitable time window for crop type classification in the HID. Sentinel-1 information played a positive role in the interannual transfer of the trained model, increasing the OA from 90.73% with Sentinel 2 alone to 91.58% with Sentinel-1 and Sentinel-2 together.
In-Flight Relative Radiometric Calibration of a Wide Field of View Directional Polarimetric Camera Based on the Rayleigh Scattering over Ocean
Authors: Zhu Sifeng , Li Zhengqiang , Qie Lili , Xu Hua , Ge Bangyu , Xie Yisong , Qiao Rui , Xie Yanqing , Hong Jin , Meng Binghuan , Tu Bihai , Chen Feinan
Published: March 2022

The directional polarimetric camera (DPC) is a Chinese satellite sensor with a large field of view (FOV) (±50° both along-track and cross-track) and a high spatial resolution (about 3.3 km at nadir) that operates in a sun-synchronous orbit. It is a difficult task to calibrate the in-flight relative radiometric variation of the sensors with such a wide FOV. In this study, a new method based on Rayleigh scattering over the ocean is developed to estimate the radiometric sensitivity variation over the whole FOV of DPC. Firstly, the theoretical uncertainty of the method is analyzed to calibrate the relative radiometric response. The calibration uncertainties are about 2–6.9% (depending on the wavelength) when the view zenith angle (VZA) is 0° and decrease to about 1–3.8% when VZA increases to 70°. Then, the method is applied to evaluate the long-term radiometric drift of the DPC. It is found that the radiometric response of DPC/GaoFen-5 over the whole FOV is progressively drifting over time. The sensitivity at shorter bands decreases more strongly than longer bands, and at the central part of the optics decreases more strongly than the marginal part. During the 14 months (from March 2019 to April 2020) of operational running in-orbit, the DPC radiometric responses of 443 nm, 490 nm, 565 nm, and 670 nm bands drifted by about 4.44–23.08%, 4.75–16.22%, 3.86–9.81%, and 4.7–16.86%, respectively, from the marginal to the central part of the FOV. The radiometric sensitivity has become more stable since January 2020. The monthly radiometric drift is separated into the relative radiometric part and the absolute radiometric part. The relative radiometric drift of DPC is found to be smoothly varying with VZA, which can be parameterized as a polynomial function via VZA. At last, the temporal radiometric drift of DPC/GaoFen-5 is corrected by combining the relative and absolute radiometric coefficients. The correction is convincing by cross calibration with MODIS/Aqua observation over the desert sites and improving the aerosol retrievals. The Rayleigh method in this study is efficient for the radiometric sensitivity calibration of wide FOV satellite sensors.
Time Series Surface Deformation of Changbaishan Volcano Based on Sentinel-1B SAR Data and Its Geological Significance
Authors: Meng Zhiguo , Shu Chuanzeng , Yang Ying , Wu Chengzhi , Dong Xuegang , Wang Dongzhen , Zhang Yuanzhi
Published: March 2022

Monitoring the surface deformation is of great significance, in order to explore the activity and geophysical features of the underground deep pressure source in the volcanic regions. In this study, the time series surface deformation of the Changbaishan volcano is retrieved via Sentinel-1B SAR data, using the SBAS-InSAR method. The main results are as follows. (1) The mean surface deformation velocity in the Changbaishan volcano is uplifted as a whole, while the uplift is locally distributed, which shows a strong correlation with faults. (2) The time series surface deformation of the Changbaishan volcano indicates an apparently seasonal change. (3) The cumulative surface deformation shows a strong correlation with the maximal magnitude and number of annual earthquakes, and it is likely dominated by the maximal magnitude of the annual earthquakes. (4) The single Mogi source model is appropriate to evaluate the deep pressure source in the Changbaishan volcano, constrained by the calculated surface deformation. The optimal estimated depth of the magma chamber is about 6.2 km, and the volume is increased by about 3.2 × 106 m3. According to the time series surface deformation, it is concluded that the tectonic activity and faults, related to the deep pressure source, are pretty active in the Changbaishan volcano.
A Two-Source Normalized Soil Thermal Inertia Model for Estimating Field-Scale Soil Moisture from MODIS and ASTER Data
Authors: Hao Guibin , Su Hongbo , Zhang Renhua , Tian Jing , Chen Shaohui
Published: March 2022

Soil moisture (SM) is a crucial component for understanding, modeling, and forecasting terrestrial water cycles and energy budgets. However, estimating field-scale SM based on thermal infrared remote-sensing data is still a challenging task. In this study, an improved Flexible Spatiotemporal DAta Fusion (FSDAF) method based on land-surface Diurnal Temperature Cycle (DTC) model (DFSDAF) was proposed to fuse Moderate Resolution Imaging Spectroradiometer (MODIS) and Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) land-surface temperature (LST) data to generate ASTER-like LST during the night. The reconstructed diurnal LST data at a high spatial resolution (90 m) was then utilized to drive a two-source normalized soil thermal inertia model (TNSTI) for the vegetated surfaces to estimate field-scale SM. The results of the proposed methods were validated at different observation depths (2, 4, 10, 20, 40, 60, and 100 cm) over the Zhangye oasis in the middle region of the Heihe River basin in the northwest of China and were compared with the SM estimates from the TNSTI model and other SM products, including AMSR2/AMSR-E, GLDAS-Noah, and ERA5-land. The results showed the following: (1) The DFSDAF method increased the accuracy of LST prediction, with the determination coefficient (R2) increasing from 0.71 to 0.77, and root mean square error (RMSE) decreasing from 2.17 to 1.89 K. (2) the estimated SMs had the best correlation with the observations at the 10 cm depth (with R2 of 0.657; RMSE of 0.069 m3/m3), but the worst correlation with observations at the 40 cm depth (with R2 of 0.262; RMSE of 0.092 m3/m3); meanwhile, the modeled SMs were significantly underestimated above 40 cm (2, 4, 10, and 20 cm) and slightly overestimated below 40 cm (60 and 100 cm); in addition, the field-scale SM series at high spatial resolution (90 m) showed significant spatiotemporal variation. (3) The SM estimates based on the TNSTI for the vegetated surfaces are more capable of characterizing the SM status in the root zone (~80 cm) or even deeper, while the SMs from AMSR2/AMSR-E, GLDAS-Noah, or ERA5-land products are closer to the SM in the surface layer (the depth is less than 5 cm). The TNSTI provided favorable data supports for hydrological model simulations and showed potential advantages for agricultural refinement managements and smart agriculture.
Analysis of the Food Loss and Waste Valorisation of Animal By-Products from the Retail Sector
Authors: Pinto João , Boavida-Dias Rui , Matos Henrique A. , Azevedo João
Published: March 2022

The meat industry generates a large amount of animal by-products not only derived from the slaughter process but also due to the losses and waste of meat products along the supply chain, contributing to the world’s food loss and waste problem. Yearly, 1.7 Mt of meat in the European retail sector and 20% of meat for consumption is wasted in this sector of the supply chain. Therefore, the aim of this paper was to find and evaluate alternatives for the valorisation of agri-food residues, more specifically the meat waste from the food retail sector, through a technological perspective. Thus, we delve into the industrial processes already implemented and the emerging procedures that use muscle, bones and fats by-products from poultry, cattle and pork as the main raw materials in order to identify and characterise them. The results indicate that in addition to the current destinations—landfill, incineration and the rendering process—these animal by-products can be incorporated in the production of biodiesel, food formulations, pharmaceuticals, fertilisers and biogas through an industrial symbiosis approach. Consequently, the several valorisation processes and procedures identified not only suggest an increase in concern about the impacts of the disposal of these materials, but also highlight the potential associated with the use of animal by-products as raw material to obtain added-value products.
Urban Densification Effect on Micrometeorology in Santiago, Chile: A Comparative Study Based on Chaos Theory
Authors: Pacheco Patricio , Mera Eduardo , Salini Giovanni
Published: March 2022

The concentration distribution of anthropocentric pollutants is favored by urban densification, affecting the micrometeorology in big cities. To examine this condition, chaos theory was applied to time series of measurements of urban meteorology and pollutants of six communes of the Metropolitan Region of Santiago de Chile, in two periods: 2010–2013 and 2017–2020. Each commune contributes, per period, six different time series: three for the meteorological variables (temperature, relative humidity, and magnitude wind speed) and three for the atmospheric pollutant concentrations (PM10, PM2.5, and CO). This qualitative study corroborates that each of the time series is chaotic through the calculation of chaotic parameters: Lyapunov exponent, correlation dimension, Hurst coefficient, correlation entropy, Lempel–Ziv complexity and fractal dimension. The variation in the chaotic parameters between the two periods can be interpreted in relation to the roughness change due to urban densification. More specific parameters, constructed from the Kolmogorov entropies and the fractal dimensions of the time series, show modifications due to the increase in the built surface in the most current period. This variation also extends to micrometeorology, as is clear from the Lempel–Ziv complexity and the Hurst coefficient. The qualitative picture constructed using chaos theory reveals that human interaction with nature affects diversity and sustainability and generates irreversible processes.
Adaptation Strategies to Climate Change and Impacts on Household Income and Food Security: Evidence from Sahelian Region of Niger
Authors: Zakari Seydou , Ibro Germaine , Moussa Bokar , Abdoulaye Tahirou
Published: March 2022

Sahelian countries, particularly Niger, are more vulnerable to climate change due to the high dependence of most of their populations on rain-fed agriculture and limited capacities to respond to climate variability and change. This paper examines the factors influencing climate change adaptation strategies and the impacts on household income and food security in rural Niger. For this purpose, we collected data from 1783 valid rural households in four main agricultural regions of Niger. The results showed that crop diversification (72.74%), income diversification (67.97%) and changing planting times (55%) are the main adaptation strategies adopted by households. The majority of respondents had noticed changes in rain patterns (93.21%), in the amount of rain (91.25%) and in the intensity of rain (81.82%) during the last five years. We categorized these adaptation strategies into six major groups namely climate-resilient crop varieties, improved agronomic practices, irrigation and water conservation practices, crop diversification, income diversification, and agroforestry. We ran logit regression to identify the determinants of each individual group. The results show mixed effects of independent variables on these categories of adaptation strategies. Using matching techniques, we found adaptation strategies have positive and significant impact on both household income and food security. The farmers who adopt climate change adaptation strategies are more likely to increase household income by 7721.526 FCFA compared to those households with zero adaptation strategies. Similarly, the adapters have 7% to 9% more chance to be food secure compared to those who did not adopt strategies. These results suggest that strengthening the awareness of the effects of climate change on farmers and the choice of appropriate adaptation strategies are necessary to enhance household resilience. Strengthening institutional factors such as access to credit and market, extension services, and using drought-resilient crop varieties would surely improve agricultural production.
Impact of Digital Inequality on the COVID-19 Pandemic: Evidence from European Union Countries
Authors: Borda Marta , Grishchenko Natalia , Kowalczyk-Rólczyńska Patrycja
Published: March 2022

One of the consequences of the COVID-19 pandemic is the relationship between social distancing measures and increased use of the Internet, electronic services, and digital devices. How does digital inequality in the context of social distancing affect the COVID-19 pandemic? In this article, we assessed the impact of existing digital inequality as the cause of the changing number of cases of COVID-19 in the EU. We assessed the relationship between the increase in COVID-19 cases between the first and second waves in 2020 and the presence of digital inequality in Internet use and digital skills across sociodemographic factors: gender, age, education, generation, marital status, and place of residence. We applied the ordinary least squares method to data from the 2019 Eurobarometer survey, which reveals the digital maturity of EU citizens, and from the European Center for Disease Prevention and Control in 2020, which tracks COVID-19 cases. We found that the strongest relationship between the number of COVID-19 cases and digital inequality is related to Internet use rather than digital skills. The digital divide by age, between generations, and the geographic digital divide in Internet use show a strong positive relationship with the changing incidence of COVID-19 cases. The gender digital gap shows a negative relationship for both Internet use and digital skills, indicating the social role of women in households in the pandemic, caring for children and the elderly. A negative relation was also found in digital inequality by marital status for digital skills, which reflects preferences regarding living alone during the pandemic. These findings prove the importance of universal access to the Internet for older people and those living in rural areas. The results can contribute to policies aimed at reducing digital inequalities in the face of the ongoing COVID-19 pandemic.