bluuebunny/crossref_metadata_2025 huggingface dataset:
Supporting Physiological Trait for Indirect Selection for Grain Yield in Drought-Stressed Popcorn
Authors: Kamphorst Samuel Henrique , Gonçalves Gabriel Moreno Bernardo , Amaral Júnior Antônio Teixeira do , Lima Valter Jário de , Schmitt Kátia Fabiane Medeiros , Leite Jhean Torres , Azeredo Valdinei Cruz , Gomes Letícia Peixoto , Silva José Gabriel de Souza , Carvalho Carolina Macedo , Mafra Gabrielle Sousa , Daher Rogério Figueiredo , Campostrini Eliemar
Published: July 2021

The identification of traits associated with drought tolerance in popcorn is a contribution to support selection of superior plants under soil water deficit. The objective of this study was to choose morphological traits and the leaf greenness index, measured on different dates, to estimate grain yield (GY) and popping expansion (PE), evaluated in a set of 20 popcorn lines with different genealogies, estimated by multiple regression models. The variables were divided into three groups: morpho-agronomic traits—100-grain weight (GW), prolificacy (PR), tassel length (TL), number of tassel branches, anthesis-silking interval, leaf angle (FA) and leaf rolling (FB); variables related to the intensity of leaf greenness during the grain-filling period, at the leaf level, measured by a portable chlorophyll meter (SPAD) and at the canopy level, calculated as the normalized difference vegetation index (NDVI). The inbred lines were cultivated under two water conditions: well-watered (WW), maintained at field capacity, and water stress (WS), for which irrigation was stopped before male flowering. The traits GY (55%) and PE (28%) were most affected by water restriction. Among the morpho-agronomic traits, GW and PR were markedly reduced (>10%). Under dry conditions, the FA in relation to the plant stalk tended to be wider, the FB curvature greater and leaf senescence accelerated (>15% at 22 days after male flowering). The use of multiple regression for the selection of predictive traits proved to be a useful tool for the identification of groups of adequate traits to efficiently predict the economically most important features of popcorn (GY and PE). The SPAD index measured 17 days after male flowering proved useful to select indirectly for GY, while, among the morphological traits, TL stood out for the same purpose. Of all traits, PR was most strongly related with PE under WS, indicating its use in breeding programs. The exploitation of these traits by indirect selection is expected to induce increments in GY and PE.
Immune Priming Triggers Cell Wall Remodeling and Increased Resistance to Halo Blight Disease in Common Bean
Authors: De la Rubia Alfonso Gonzalo , Mélida Hugo , Centeno María Luz , Encina Antonio , García-Angulo Penélope
Published: July 2021

The cell wall (CW) is a dynamic structure extensively remodeled during plant growth and under stress conditions, however little is known about its roles during the immune system priming, especially in crops. In order to shed light on such a process, we used the Phaseolus vulgaris-Pseudomonas syringae (Pph) pathosystem and the immune priming capacity of 2,6-dichloroisonicotinic acid (INA). In the first instance we confirmed that INA-pretreated plants were more resistant to Pph, which was in line with the enhanced production of H2O2 of the primed plants after elicitation with the peptide flg22. Thereafter, CWs from plants subjected to the different treatments (non- or Pph-inoculated on non- or INA-pretreated plants) were isolated to study their composition and properties. As a result, the Pph inoculation modified the bean CW to some extent, mostly the pectic component, but the CW was as vulnerable to enzymatic hydrolysis as in the case of non-inoculated plants. By contrast, the INA priming triggered a pronounced CW remodeling, both on the cellulosic and non-cellulosic polysaccharides, and CW proteins, which resulted in a CW that was more resistant to enzymatic hydrolysis. In conclusion, the increased bean resistance against Pph produced by INA priming can be explained, at least partially, by a drastic CW remodeling.
Recent Progress of Rice Husk Reinforced Polymer Composites: A Review
Authors: Suhot Mohamed Azlan , Hassan Mohamad Zaki , Aziz Sa’ardin Abdul , Md Daud Mohd Yusof
Published: July 2021

Recently, because of the rising population, carbon overloading, and environmental distress, human beings have needed to increase awareness and responsibility for the reduction of agricultural waste. The utilization of agricultural waste as a filler material in reinforced polymers is a fascinating discovery. This review paper attempts to study the physical, mechanical, and thermal behavior of rice husk (RH) as a fiber for reinforcing various synthetic polymers, based on recent studies, conducted between 2017 and 2021. It also highlights that advanced modification techniques could further improve the performance of composites by tailoring the physical and chemical substances of the fiber or matrix. The thermal properties, including flame-retardance and thermal behavior, are also discussed. The characteristics of the fiber–matrix interaction between RH and the polymer matrix provide essential insights into the future-ready applications of this agricultural waste fiber. The way forward in researching RH polymer composites is finally reviewed.
Precise Controlled Target Molecule Release through Light-Triggered Charge Reversal Bridged Polysilsesquioxane Nanoparticles
Authors: Zhang Xin , Zhang Mengmeng , Wu Mingyue , Yang Linchuan , Liu Rui , Zhang Rui , Zhao Tongtong , Song Ci , Liu Gang , Zhu Qingzeng
Published: July 2021

Precise control of target molecule release time, site, and dosage remains a challenge in controlled release systems. We employed a photoresponsive molecule release system via light-triggered charge reversal nanoparticles to achieve a triggered, stepwise, and precise controlled release platform. This release system was based on photocleavage-bridged polysilsesquioxane nanoparticles which acted as nanocarriers of doxorubicin loaded on the surface via electrostatic interaction. The nanoparticles could reverse into positive charges triggered by 254 nm light irradiation due to the photocleavage of the o-nitrobenzyl bridged segment. The charge reversal property of the nanoparticles could release loaded molecules. Doxorubicin was selected as a positively charged model molecule. The as-prepared nanoparticles with an average size of 124 nm had an acceptable doxorubicin loading content up to 12.8%. The surface charge of the nanoparticles could rapidly reverse from negative (−28.20 mV) to positive (+18.9 mV) upon light irradiation for only 10 min. In vitro release experiments showed a cumulative release up to 96% with continuously enhancing irradiation intensity. By regulating irradiation parameters, precisely controlled drug release was carried out. The typical “stepped” profile could be accurately controlled in an on/off irradiation mode. This approach provides an ideal light-triggered molecule release system for location, timing, and dosage. This updated controlled release system, triggered by near-infrared or infrared light, will have greater potential applications in biomedical technology.
Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique
Authors: Tanigaki Nobutaka , Takechi Chikayo , Nagamatsu Shuichi , Mizokuro Toshiko , Yoshida Yuji
Published: July 2021

A thin film of unsubstituted polythiophene (PT), an insoluble conjugated polymer, with molecular chains uniaxially oriented in plane was prepared by the friction transfer method. The structure of highly oriented thin films of PT was investigated using grazing-incidence X-ray diffraction (GIXD), ultraviolet–visible (UV–vis) spectroscopy, and infrared (IR) spectroscopy. The polarized UV–vis and IR spectra and GIXD measurements showed the PT molecular chains were well aligned in parallel to the friction direction. The GIXD studies clarified that the polymer backbones were aligned with very narrow distribution, such that the half-width was about 4 degrees. The degree of orientation of the PT friction-transferred film was higher compared with those of regioregular poly(3-alkylthiophene)s. Moreover, the GIXD results show a preferred orientation where the a-axis is perpendicular to the substrate plane.
Formulation of DNA Nanocomposites: Towards Functional Materials for Protein Expression
Authors: Schipperges Alessa , Hu Yong , Moench Svenja , Weigel Simone , Reith Johannes , Ordoñez-Rueda Diana , Rabe Kersten S. , Niemeyer Christof M.
Published: July 2021

DNA hydrogels are an emerging class of materials that hold great promise for numerous biotechnological applications, ranging from tissue engineering to targeted drug delivery and cell-free protein synthesis (CFPS). In addition to the molecular programmability of DNA that can be used to instruct biological systems, the formulation of DNA materials, e.g., as bulk hydrogels or microgels, is also relevant for specific applications. To advance the state of knowledge in this research area, the present work explores the scope of a recently developed class of complex DNA nanocomposites, synthesized by RCA polymerization of DNA-functionalized silica nanoparticles (SiNPs) and carbon nanotubes (CNTs). SiNP/CNT–DNA composites were produced as bulk materials and microgels which contained a plasmid with transcribable genetic information for a fluorescent marker protein. Using confocal microscopy and flow cytometry, we found that the materials are very efficiently taken up by various eukaryotic cell lines, which were able to continue dividing while the ingested material was evenly distributed to the daughter cells. However, no expression of the encoded protein occurred within the cells. While the microgels did not induce production of the marker protein even in a CFPS procedure with eukaryotic cell lysate, the bulk composites proved to be efficient templates for CFPS. This work contributes to the understanding of the molecular interactions between DNA composites and the functional cellular machinery. Implications for the use of such materials for CFPS procedures are discussed.
Composite Anion Exchange Membranes Fabricated by Coating and UV Crosslinking of Low-Cost Precursors Tested in a Redox Flow Battery
Authors: Charyton Martyna , Deboli Francesco , Fischer Peter , Henrion Gerard , Etienne Mathieu , Donten Mateusz L.
Published: July 2021

This paper presents a novel, cost-effective approach to the fabrication of composite anion exchange membranes (AEMs). Hierarchical AEMs have been fabricated by coating a porous substrate with an interpenetrating polymer network (IPN) layer where poly(vinylpyrrolidone) (PVP) is immobilized in a crosslinked matrix. The IPN matrix was formed by UV initiated radical crosslinking of a mixture of acrylamide-based monomers and acrylic resins. The fabricated membranes have been compared with a commercial material (Fumatech FAP 450) in terms of ionic transport properties and performance in a vanadium redox flow battery (VRFB). Measures of area-specific resistance (ASR) and vanadium permeability for the proposed membranes demonstrated properties approaching the commercial benchmark. These properties could be tuned by changing the content of PVP in the IPN coating. Higher PVP/matrix ratios facilitate a higher water uptake of the coating layer and thus lower ASR (as low as 0.58 Ω.cm2). On the contrary, lower PVP/matrix ratios allow to reduce the water uptake of the coating and hence decrease the vanadium permeability at the cost of a higher ASR (as high as 1.99 Ω.cm2). In VRFB testing the hierarchical membranes enabled to reach energy efficiency comparable with the commercial AEM (PVP_14—74.7%, FAP 450—72.7% at 80 mA.cm−2).
Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite
Authors: Santos Leandra P. , da Silva Douglas S. , Morari Thais H. , Galembeck Fernando
Published: July 2021

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.
Optimization of Thick-Walled Viscoelastic Hollow Polymer Cylinders by Artificial Heterogeneity Creation: Theoretical Aspects
Authors: Chepurnenko Anton , Litvinov Stepan , Meskhi Besarion , Beskopylny Alexey
Published: July 2021

A theoretical solution of the problem of thick-walled shell optimization by varying the mechanical characteristics of the material over the thickness of the structure is proposed, taking into account its rheological properties. The optimization technique is considered by the example of a cylindrical shell made of high-density polyethylene with hydroxyapatite subjected to internal pressure. Radial heterogeneity can be created by centrifugation during the curing of the polymer mixed with the additive. The nonlinear Maxwell–Gurevich equation is used as the law describing polymer creep. The relationship of the change in the additive content along with the radius r, at which the structure is equally stressed following the four classical criteria of fracture, is determined in an elastic formulation. Moreover, it is shown that a cylinder with equal stress at the beginning of the creep process ceases to be equally stressed during creep. Finally, an algorithm for defining the relationship of the additive mass content on coordinate r, at which the structure is equally stressed at the end of the creep process, is proposed. The developed algorithm, implemented in the MATLAB software, allows modeling both equally stressed and equally strength structures.
Manufacturing PLA/PCL Blends by Ultrasonic Molding Technology
Authors: Ferrer Inés , Manresa Ariadna , Méndez José Alberto , Delgado-Aguilar Marc , Garcia-Romeu Maria Luisa
Published: July 2021

Ultrasonic molding (USM) is a good candidate for studying the plasticization of polymer mixtures or other composite materials due to either the little amount of material needed for processing, low waste or the needed low pressure and residence time of the mold. Thus, the novelty of this research is the capability of USM technology to process PLA/PCL blends and their corresponding neat materials, encompassing all the production stages, from raw material to the final specimen. The major findings of the work revealed that the thermal properties of the blends were not affected by the USM process, although the crystallinity degree experienced variations, decreasing for PLA and increasing for PCL, which was attributed to the crystallization rate of each polymer, the high process speed, the short cooling time and the small particle size. The employed ultrasonic energy increased the molecular weight with low variations through the specimen. However, the degradation results aligned with the expected trend of these material blends. Moreover, this study also showed the effect pellet shape and dimensions have over the process parameters, as well as the effect of the blend composition. It can be concluded that USM is a technology suitable to successfully process PLA/PCL blends with the correct determination of process parameter windows.
Counter-Acting Candida albicans-Staphylococcus aureus Mixed Biofilm on Titanium Implants Using Microbial Biosurfactants
Authors: Tambone Erica , Marchetti Alice , Ceresa Chiara , Piccoli Federico , Anesi Adriano , Nollo Giandomenico , Caola Iole , Bosetti Michela , Fracchia Letizia , Ghensi Paolo , Tessarolo Francesco
Published: July 2021

This study aimed to grow a fungal-bacterial mixed biofilm on medical-grade titanium and assess the ability of the biosurfactant R89 (R89BS) coating to inhibit biofilm formation. Coated titanium discs (TDs) were obtained by physical absorption of R89BS. Candida albicans-Staphylococcus aureus biofilm on TDs was grown in Yeast Nitrogen Base, supplemented with dextrose and fetal bovine serum, renewing growth medium every 24 h and incubating at 37 °C under agitation. The anti-biofilm activity was evaluated by quantifying total biomass, microbial metabolic activity and microbial viability at 24, 48, and 72 h on coated and uncoated TDs. Scanning electron microscopy was used to evaluate biofilm architecture. R89BS cytotoxicity on human primary osteoblasts was assayed on solutions at concentrations from 0 to 200 μg/mL and using eluates from coated TDs. Mixed biofilm was significantly inhibited by R89BS coating, with similar effects on biofilm biomass, cell metabolic activity and cell viability. A biofilm inhibition >90% was observed at 24 h. A lower but significant inhibition was still present at 48 h of incubation. Viability tests on primary osteoblasts showed no cytotoxicity of coated TDs. R89BS coating was effective in reducing C. albicans-S. aureus mixed biofilm on titanium surfaces and is a promising strategy to prevent dental implants microbial colonization.
Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR
Authors: Witek Magdalena , Krzystyniak Maciej , Romanelli Giovanni , Witczak Teresa
Published: July 2021

Experimental protocols aiming at the characterisation of glass transition often suffer from ambiguity. The ambition of the present study is to describe the glass transition in a complex, micro heterogeneous system, the dry rice pasta, in a most unambiguous manner, minimising the influence of technique-specific bias. To this end, we apply an unprecedented combination of experimental techniques. Apart from the usually used NMR and DSC, we employ, in a concurrent manner, neutron transmission, diffraction, and Compton scattering. This enables us to investigate the glass transition over a range of spatio-temporal scales that stretches over seven orders of magnitude. The results obtained by neutron diffraction and DSC reveal that dry rice pasta is almost entirely amorphous. Moreover, the glass transition is evidenced by neutron transmission and diffraction data and manifested as a significant decrease of the average sample number density in the temperature range between 40 and 60 °C. At the microscopic level, our NMR, neutron transmission and Compton scattering results provide evidence of changes in the secondary structure of the starch within the dry rice pasta accompanying the glass transition, whereby the long-range order provided by the polymer structure within the starch present in the dry rice pasta is partially lost.
Development Process of Energy Mix towards Neutral Carbon Future of the Slovak Republic: A Review
Authors: Beer Martin , Rybár Radim
Published: July 2021

Global climate change is putting humanity under pressure, which in many areas poses an unprecedented threat to society as we know it. In an effort to mitigate its effects, it is necessary to reduce the overall production of greenhouse gases and thus, dependence on fossil fuels in all areas of human activities. The presented paper deals with an evaluation of energy mix of the Slovak Republic and four selected neighboring countries in the context of achieving their carbon neutral or carbon negative future. The development of the evaluated energy mixes as well as greenhouse gas emissions is presented from a long-term perspective, which makes it possible to evaluate and compare mutual trends and approaches to emission-free energy sectors.
How Does Environmental Regulation Affect the Relationship between FDI and Technological Innovation: From the Perspective of Technology Transactions
Authors: Zeng Meng , Liu Lihang , Zhou Fangyi , Xiao Yigui
Published: July 2021

Many studies have found that FDI can reduce the pollutant emissions of host countries. At the same time, the intensity of environmental regulation would affect the emission reduction effect of FDI in the host country. This study aims to reveal the internal mechanisms of this effect. Specifically, this paper studies the impact of FDI on technological innovation in China’s industrial sectors from the perspective of technology transactions from 2001 to 2019, and then analyzes whether the intensity of environmental regulation can promote the relationship. Results indicate that FDI promotes technological innovation through technology transactions. In addition, it finds that the intensity of environmental regulation significantly positively moderates the relationship between FDI and technological innovation, which is achieved by positively moderating the FDI–technology transaction relationship. Regional heterogeneity analysis is further conducted, and results show that in the eastern and western regions of China, FDI can stimulate technological innovation within regional industrial sectors through technology trading. Moreover, environmental regulation has a significant positive regulatory effect on the above relationship, but these effects are not supported by evidence in the central region of China.
The Ancient Artificial Leg of Capua: First 3D Print after 2300 Years
Authors: Otte Andreas , Hazubski Simon
Published: July 2021

Little detail has been reported about the ancient Capua leg, which was excavated in the winter of 1884/85 a few kilometers from the present-day Campanian town of Santa Maria Capua Vetere and dated to about 300 B.C. [...]
Fischer–Tropsch Synthesis for Light Olefins from Syngas: A Review of Catalyst Development
Authors: Yahyazadeh Arash , Dalai Ajay K. , Ma Wenping , Zhang Lifeng
Published: July 2021

Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA).
Beyond the Phenomenology of the Inconspicuous
Authors: Canullo Carla
Published: July 2021

How does spirit appear? In fact, it does not appear, and for this reason, we could refer to it, following Heidegger, as “inconspicuous” (unscheinbar). The Heideggerian path investigates this inconspicuous starting from the Husserlian method, and yet, this is not the only Phenomenology of the “Inconspicuous” Spirit: Hegel had already thematized it in 1807. It is thus possible to identify at least two Phenomenologies of the “Inconspicuous” spirit. These two phenomenologies, however, do not simply put forth distinct phenomenological methods, nor do they merely propose differing modes of spirit’s manifestation. In each of these phenomenologies, rather, what we call “spirit” manifests different traits: in one instance, it appears as absolute knowing, and, in the other, it manifests “from itself” as “phenomenon”. Yet how, exactly, does spirit manifest “starting from itself as phenomenon”? Certainly not in the mode of entities, but rather in the modality that historical phenomenology, which also includes Edmund Husserl’s work, has grasped. A question remains, however: is the inconspicuous coextensive with “spirit”? Certainly, spirit is inconspicuous, but it is not only spirit that is such. A certain phenomenological practice understood this well, a practice that several French authors have pushed. Jean-Luc Marion, Michel Henry, and Jean-Louis Chrétien have all contributed, in a certain way, to the phenomenology of the inconspicuous. However, do these authors carry out a phenomenology of inconspicuous spirit? Perhaps what French phenomenology gives us today, after an itinerary that has discovered several senses of the inconspicuous, is precisely the return to spirit that is missing in, and was missed by, this tradition.
Solidarity Actions Based on Religious Plurality
Authors: de Botton Lena , Aiello Emilia , Padrós Maria , Melgar Patricia
Published: July 2021

The successive crises experienced recently (financial crisis in 2008, refugees in 2015 and the current crisis resulting from COVID) have led to surges in discrimination, racism and lack of solidarity between groups. However, these same crises have inspired important manifestations of solidarity with a significant social impact (improving people’s lives) for many groups and in very different areas. This article focuses on two solidarity initiatives (interreligious language pairs and a cooperative) that contribute to overcoming inequalities and the social exclusion of the most vulnerable groups, to explore whether religious plurality and the interreligious dialogue present in these initiatives are a favourable element for solidarity.
Conscience: An Investigation in Stenian Philosophy in Relation to Bioethics
Authors: Lamb Christina
Published: July 2021

This article investigates how Edith Stein’s philosophical work on conscience is relevant for appreciating conscience today. In particular, this article shows how Stein’s contributions to conscience explicates what it is and why it is relevant for moral decision making. Moral decision making is necessary in bioethics and healthcare. However, leading bioethicists today lack an understanding of what conscience is, how it applies to healthcare practice and why it should be respected. Recent developments in obligatory referrals for healthcare professionals reveal further challenges related to appreciating conscience in current bioethical contexts. In this article, I consider the importance of Stein’s work on conscience to address the gap in knowledge related to conscience in bioethics today. To do so, I will outline the main aspects of Stein’s phenomenological and metaphysical approaches to the psycho-spiritual-physical aspects of being human. I will then describe her work on conscience. Next, I will discuss how contemplation vis à vis the Catholic imagination could provide a way to perceive how conscience is a response to morality. Finally, I will show how Stein’s work can refute contemporary approaches to conscience and obligatory referral.
Urban Sprawl and Changes in Land-Use Efficiency in the Beijing–Tianjin–Hebei Region, China from 2000 to 2020: A Spatiotemporal Analysis Using Earth Observation Data
Authors: Zhou Meiling , Lu Linlin , Guo Huadong , Weng Qihao , Cao Shisong , Zhang Shuangcheng , Li Qingting
Published: July 2021

Sustainable development in urban areas is at the core of the implementation of the UN 2030 Agenda and the Sustainable Development Goals (SDG). Analysis of SDG indicator 11.3.1—Land-use efficiency based on functional urban boundaries—provides a globally harmonized avenue for tracking changes in urban settlements in different areas. In this study, a methodology was developed to map built-up areas using time-series of Landsat imagery on the Google Earth Engine cloud platform. By fusing the mapping results with four available land-cover products—GlobeLand30, GHS-Built, GAIA and GLC_FCS-2020—a new built-up area product (BTH_BU) was generated for the Beijing–Tianjin–Hebei (BTH) region, China for the time period 2000–2020. Using the BTH_BU product, functional urban boundaries were created, and changes in the size of the urban areas and their form were analyzed for the 13 cities in the BTH region from 2000 to 2020. Finally, the spatiotemporal dynamics of SDG 11.3.1 indicators were analyzed for these cities. The results showed that the urban built-up area could be extracted effectively using the BTH_BU method, giving an overall accuracy and kappa coefficient of 0.93 and 0.85, respectively. The overall ratio of the land consumption rate to population growth rate (LCRPGR) in the BTH region fluctuated from 1.142 in 2000–2005 to 0.946 in 2005–2010, 2.232 in 2010–2015 and 1.538 in 2015–2020. Diverged changing trends of LCRPGR values in cities with different population sizes in the study area. Apart from the megacities of Beijing and Tianjin, after 2010, the LCRPGR values were greater than 2 in all the cities in the region. The cities classed as either small or very small had the highest LCRPGR values; however, some of these cities, such as Chengde and Hengshui, experienced population loss in 2005–2010. To mitigate the negative impacts of low-density sprawl on environment and resources, local decision makers should optimize the utilization of land resources and improve land-use efficiency in cities, especially in the small cities in the BTH region.
Parallel Point Clouds: Hybrid Point Cloud Generation and 3D Model Enhancement via Virtual–Real Integration
Authors: Tian Yonglin , Wang Xiao , Shen Yu , Guo Zhongzheng , Wang Zilei , Wang Fei-Yue
Published: July 2021

Three-dimensional information perception from point clouds is of vital importance for improving the ability of machines to understand the world, especially for autonomous driving and unmanned aerial vehicles. Data annotation for point clouds is one of the most challenging and costly tasks. In this paper, we propose a closed-loop and virtual–real interactive point cloud generation and model-upgrading framework called Parallel Point Clouds (PPCs). To our best knowledge, this is the first time that the training model has been changed from an open-loop to a closed-loop mechanism. The feedback from the evaluation results is used to update the training dataset, benefiting from the flexibility of artificial scenes. Under the framework, a point-based LiDAR simulation model is proposed, which greatly simplifies the scanning operation. Besides, a group-based placing method is put forward to integrate hybrid point clouds, via locating candidate positions for virtual objects in real scenes. Taking advantage of the CAD models and mobile LiDAR devices, two hybrid point cloud datasets, i.e., ShapeKITTI and MobilePointClouds, are built for 3D detection tasks. With almost zero labor cost on data annotation for newly added objects, the models (PointPillars) trained with ShapeKITTI and MobilePointClouds achieved 78.6% and 60.0% of the average precision of the model trained with real data on 3D detection, respectively.
Unoccupied Aircraft Systems (UASs) Reveal the Morphological Changes at Stromboli Volcano (Italy) before, between, and after the 3 July and 28 August 2019 Paroxysmal Eruptions
Authors: Civico Riccardo , Ricci Tullio , Scarlato Piergiorgio , Andronico Daniele , Cantarero Massimo , Carr Brett B. , De Beni Emanuela , Del Bello Elisabetta , Johnson Jeffrey B. , Kueppers Ulrich , Pizzimenti Luca , Schmid Markus , Strehlow Karen , Taddeucci Jacopo
Published: July 2021

In July and August 2019, two paroxysmal eruptions dramatically changed the morphology of the crater terrace that hosts the active vents of Stromboli volcano (Italy). Here, we document these morphological changes, by using 2259 UAS-derived photographs from eight surveys and Structure-from-Motion (SfM) photogrammetric techniques, resulting in 3D point clouds, orthomosaics, and digital surface models (DSMs) with resolution ranging from 8.1 to 12.4 cm/pixel. We focus on the morphological evolution of volcanic features and volume changes in the crater terrace and the upper part of the underlying slope (Sciara del Fuoco). We identify both crater terrace and lava field variations, with vents shifting up to 47 m and the accumulation of tephra deposits. The maximum elevation changes related to the two paroxysmal eruptions (in between May and September 2019) range from +41.4 to −26.4 m at the lava field and N crater area, respectively. Throughout September 2018–June 2020, the total volume change in the surveyed area was +447,335 m3. Despite Stromboli being one of the best-studied volcanoes worldwide, the UAS-based photogrammetry products of this study provide unprecedented high spatiotemporal resolution observations of its entire summit area, in a period when volcanic activity made the classic field inspections and helicopter overflights too risky. Routinely applied UAS operations represent an effective and evolving tool for volcanic hazard assessment and to support decision-makers involved in volcanic surveillance and civil protection operations.
AlgaeMAp: Algae Bloom Monitoring Application for Inland Waters in Latin America
Authors: Lobo Felipe de Lucia , Nagel Gustavo Willy , Maciel Daniel Andrade , Carvalho Lino Augusto Sander de , Martins Vitor Souza , Barbosa Cláudio Clemente Faria , Novo Evlyn Márcia Leão de Moraes
Published: July 2021

Due to increasing algae bloom occurrence and water degradation on a global scale, there is a demand for water quality monitoring systems based on remote sensing imagery. This paper describes the scientific, theoretical, and methodological background for creating a cloud-computing interface on Google Earth Engine (GEE) which allows end-users to access algae bloom related products with high spatial (30 m) and temporal (~5 day) resolution. The proposed methodology uses Sentinel-2 images corrected for atmospheric and sun-glint effects to generate an image collection of the Normalized Difference Chlorophyll-a Index (NDCI) for the entire time-series. NDCI is used to estimate both Chl-a concentration, based on a non-linear fitting model, and Trophic State Index (TSI), based on a tree-decision model classification into five classes. Once the Chl-a and TSI algorithms had been calibrated and validated they were implemented in GEE as an Earth Engine App, entitled Algae Bloom Monitoring Application (AlgaeMAp). AlgaeMAp is the first online platform built within the GEE platform that offers high spatial resolution of water quality parameters. The App benefits from the huge processing capability of GEE that allows any user with internet access to easily extract detailed spatial (30 m) and long temporal Chl-a and TSI information (from August 2015 and with images every 5 days) throughout the most important reservoirs in the State of São Paulo/Brazil. The application will be adapted to extend to other relevant areas in Latin America.
Spatial, Phenological, and Inter-Annual Variations of Gross Primary Productivity in the Arctic from 2001 to 2019
Authors: Ma Dujuan , Wu Xiaodan , Ma Xuanlong , Wang Jingping , Lin Xingwen , Mu Cuicui
Published: July 2021

Quantifying the spatial, seasonal (phenological), and inter-annual variations of gross primary productivity (GPP) in the Arctic is critical for comprehending the terrestrial carbon cycle and its feedback to climate warming in this region. Here, we evaluated the accuracy of the MOD17A2H GPP product using the FLUXNET 2015 dataset in the Arctic, then explored the spatial patterns, seasonal variations, and interannual trends of GPP, and investigated the dependence of the spatiotemporal variations in GPP on land cover types, latitude, and elevation from 2001 to 2019. The results showed that MOD17A2H was consistent with in situ measurements (R = 0.8, RMSE = 1.26 g C m−2 d−1). The functional phenology was also captured by the MOD17A2H product (R = 0.62, RMSE = 9 days) in the Arctic. The spatial variation of the seasonal magnitude of GPP and its interannual trends is partly related to land cover types, peaking in forests and lowest in grasslands. The interannual trend of GPP decreased as the latitude and elevation increased, except for the latitude between 62°~66° N and elevation below 700 m. Our study not only revealed the variation of GPP in the Arctic but also helped to understand the carbon cycle over this region.
Validation of Permafrost Active Layer Estimates from Airborne SAR Observations
Authors: Parsekian Andrew D. , Chen Richard H. , Michaelides Roger J. , Sullivan Taylor D. , Clayton Leah K. , Huang Lingcao , Zhao Yuhuan , Wig Elizabeth , Moghaddam Mahta , Zebker Howard , Schaefer Kevin
Published: July 2021

In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic and elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have emerged as a method for observing seasonal thaw subsidence, soil moisture, and ALT in permafrost regions. This study validates airborne SAR-derived ALT estimates in three regions of Alaska, USA using calibrated ground penetrating radar (GPR) geophysical data. The remotely sensed ALT estimates matched the field observations within uncertainty for 79% of locations. The average uncertainty for the GPR-derived ALT validation dataset was 0.14 m while the average uncertainty for the SAR-derived ALT in pixels coincident with GPR data was 0.19 m. In the region near Utqiaġvik, the remotely sensed ALT appeared slightly larger than field observations while in the Yukon-Kuskokwim Delta region, the remotely sensed ALT appeared slightly smaller than field observations. In the northern foothills of the Brooks Range, near Toolik Lake, there was minimal bias between the field data and remotely sensed estimates. These findings suggest that airborne SAR-derived ALT estimates compare well with in situ probing and GPR, making SAR an effective tool to monitor permafrost measurements.
Using GEDI Waveforms for Improved TanDEM-X Forest Height Mapping: A Combined SINC + Legendre Approach
Authors: Chen Hao , Cloude Shane R. , White Joanne C.
Published: July 2021

In this paper, we consider a new method for forest canopy height estimation using TanDEM-X single-pass radar interferometry. We exploit available information from sample-based, space-borne LiDAR systems, such as the Global Ecosystem Dynamics Investigation (GEDI) sensor, which offers high-resolution vertical profiling of forest canopies. To respond to this, we have developed a new extended Fourier-Legendre series approach for fusing high-resolution (but sparsely spatially sampled) GEDI LiDAR waveforms with TanDEM-X radar interferometric data to improve wide-area and wall-to-wall estimation of forest canopy height. Our key methodological development is a fusion of the standard uniform assumption for the vertical structure function (the SINC function) with LiDAR vertical profiles using a Fourier-Legendre approach, which produces a convergent series of approximations of the LiDAR profiles matched to the interferometric baseline. Our results showed that in our test site, the Petawawa Research Forest, the SINC function is more accurate in areas with shorter canopy heights (<~27 m). In taller forests, the SINC approach underestimates forest canopy height, whereas the Legendre approach avails upon simulated GEDI forest structural vertical profiles to overcome SINC underestimation issues. Overall, the SINC + Legendre approach improved canopy height estimates (RMSE = 1.29 m) compared to the SINC approach (RMSE = 4.1 m).
Near-Coast Tide Model Validation Using GNSS Unmanned Surface Vehicle (USV), a Case Study in the Pertuis Charentais (France)
Authors: Tranchant Yann-Treden , Testut Laurent , Chupin Clémence , Ballu Valérie , Bonnefond Pascal
Published: July 2021

Nowadays, uncertainties related to the determination of ocean tides remain a major issue for the exploitation of altimetry data in coastal areas. Using Sea Surface Height (SSH) observations from a new GNSS-based system mounted on an Unmanned Surface Vehicle (USV), we develop a crossover methodology to assess tide models under altimetry tracks. To this purpose, we address the Pertuis Charentais area, a semi enclosed sea located in the centre of the Bay of Biscay (France), as a field and modelling case study. We have developed a barotropic model configuration, based on SCHISM platform, using tidal elevations of an up-to-date regional atlas as boundary conditions. To test the impact of boundary conditions, we propose a second configuration where we applied uniform empirical biases in phases and amplitudes on M3 and MN4 constituents. In addition, the survey was designed to highlight the contribution of third and fourth-diurnal waves that are strongly amplified on the shelf and is used to assess model performances under the pass 216 of Sentinel-3A. Our results show that the second configuration reduces the Root-Mean-Square Error (RMSE) of the survey crossover residuals by more than 60%, leading to half of the residuals below 2.5 cm. This improved solution also reduces by 20% the RMSE computed with data from tide gauges located in the inner part of the Pertuis Charentais. Therefore, our study reinforces the importance for coastal tide modelling of an accurate tidal forcing, especially for shallow water waves. We finally discuss the impact of the remaining M4 error on crossover residual heights. By introducing an empirical correction term based on M4 observations at tide gauges, we further reduce the RMSE of crossover residuals by 15–25%. With this innovative study, we demonstrate the interest of combining crossover validation methods and USV systems to spatially extend our understanding of coastal areas dynamics. This will be crucial in the scope of the future SWOT mission, for which the tide correction accuracy must be assessed over the large-extent areas covered by swaths observations.
New Forest Aboveground Biomass Maps of China Integrating Multiple Datasets
Authors: Chang Zhongbing , Hobeichi Sanaa , Wang Ying-Ping , Tang Xuli , Abramowitz Gab , Chen Yang , Cao Nannan , Yu Mengxiao , Huang Huabing , Zhou Guoyi , Wang Genxu , Ma Keping , Du Sheng , Li Shenggong , Han Shijie , Ma Youxin , Wigneron Jean-Pierre , Fan Lei , Saatchi Sassan S. , Yan Junhua
Published: July 2021

Mapping the spatial variation of forest aboveground biomass (AGB) at the national or regional scale is important for estimating carbon emissions and removals and contributing to global stocktake and balancing the carbon budget. Recently, several gridded forest AGB products have been produced for China by integrating remote sensing data and field measurements, yet significant discrepancies remain among these products in their estimated AGB carbon, varying from 5.04 to 9.81 Pg C. To reduce this uncertainty, here, we first compiled independent, high-quality field measurements of AGB using a systematic and consistent protocol across China from 2011 to 2015. We applied two different approaches, an optimal weighting technique (WT) and a random forest regression method (RF), to develop two observationally constrained hybrid forest AGB products in China by integrating five existing AGB products. The WT method uses a linear combination of the five existing AGB products with weightings that minimize biases with respect to the field measurements, and the RF method uses decision trees to predict a hybrid AGB map by minimizing the bias and variance with respect to the field measurements. The forest AGB stock in China was 7.73 Pg C for the WT estimates and 8.13 Pg C for the RF estimates. Evaluation with the field measurements showed that the two hybrid AGB products had a lower RMSE (29.6 and 24.3 Mg/ha) and bias (−4.6 and −3.8 Mg/ha) than all five participating AGB datasets. Our study demonstrated both the WT and RF methods can be used to harmonize existing AGB maps with field measurements to improve the spatial variability and reduce the uncertainty of carbon stocks. The new spatial AGB maps of China can be used to improve estimates of carbon emissions and removals at the national and subnational scales.
3D Pedestrian Detection in Farmland by Monocular RGB Image and Far-Infrared Sensing
Authors: Tian Wei , Deng Zhenwen , Yin Dong , Zheng Zehan , Huang Yuyao , Bi Xin
Published: July 2021

The automated driving of agricultural machinery is of great significance for the agricultural production efficiency, yet is still challenging due to the significantly varied environmental conditions through day and night. To address operation safety for pedestrians in farmland, this paper proposes a 3D person sensing approach based on monocular RGB and Far-Infrared (FIR) images. Since public available datasets for agricultural 3D pedestrian detection are scarce, a new dataset is proposed, named as “FieldSafePedestrian”, which includes field images in both day and night. The implemented data augmentations of night images and semi-automatic labeling approach are also elaborated to facilitate the 3D annotation of pedestrians. To fuse heterogeneous images of sensors with non-parallel optical axis, the Dual-Input Depth-Guided Dynamic-Depthwise-Dilated Fusion network (D5F) is proposed, which assists the pixel alignment between FIR and RGB images with estimated depth information and deploys a dynamic filtering to guide the heterogeneous information fusion. Experiments on field images in both daytime and nighttime demonstrate that compared with the state-of-the-arts, the dynamic aligned image fusion achieves an accuracy gain of 3.9% and 4.5% in terms of center distance and BEV-IOU, respectively, without affecting the run-time efficiency.