bluuebunny/crossref_metadata_2025 huggingface dataset:
Root and Shoot Response to Nickel in Hyperaccumulator and Non-Hyperaccumulator Species
Authors: Rosatto Stefano , Mariotti Mauro , Romeo Sara , Roccotiello Enrica
Published: March 2021

The soil–root interface is the micro-ecosystem where roots uptake metals. However, less than 10% of hyperaccumulators’ rhizosphere has been examined. The present study evaluated the root and shoot response to nickel in hyperaccumulator and non-hyperaccumulator species, through the analysis of root surface and biomass and the ecophysiological response of the related aboveground biomass. Ni-hyperaccumulators Alyssoides utriculata (L.) Medik. and Noccaea caerulescens (J. Presl and C. Presl) F.K. Mey. and non-hyperaccumulators Alyssum montanum L. and Thlaspi arvense L. were grown in pot on Ni-spiked soil (0–1000 mg Ni kg−1, total). Development of root surfaces was analysed with ImageJ; fresh and dry root biomass was determined. Photosynthetic efficiency was performed by analysing the fluorescence of chlorophyll a to estimate the plants’ physiological conditions at the end of the treatment. Hyperaccumulators did not show a Ni-dependent decrease in root surfaces and biomass (except Ni 1000 mg kg−1 for N. caerulescens). The non-hyperaccumulator A. montanum suffers metal stress which threatens plant development, while the excluder T. arvense exhibits a positive ecophysiological response to Ni. The analysis of the root system, as a component of the rhizosphere, help to clarify the response to soil nickel and plant development under metal stress for bioremediation purposes.
BcHTT4 Inhibits Branching of Non-Heading Chinese Cabbage at the Vegetative Stage
Authors: Guo Mingliang , Xu Lanlan , Long Yan , Huang Feiyi , Liu Tongkun , Li Ying , Hou Xilin
Published: March 2021

Branching is speculated to contribute to the plant architecture and crop yield. As a quantitative trait, branching is regulated by multiple genes in non-heading Chinese cabbage (NHCC). Several related candidate genes have been discovered in previous studies on the branching of NHCC, but their specific functions and regulatory mechanisms still need to be verified and explored. In this study, we found that the expression of BcHTT4, the ortholog to HEAT-INDUCED TAS1 TARGET4 (HTT4) in Arabidopsis, was significantly different between ‘Suzhouqing’ (common type) and ‘Maertou’ (multiple shoot branching type) in NHCC, which was consistent with the previous transcriptome sequencing results. The silencing of BcHTT4 expression in non-heading Chinese cabbage promotes axillary bud growth at the vegetative stage. When BcHTT4 is overexpressed in Arabidopsis, branching will decrease. In further study, we found that BcHTT4 interacts with immunophilin BcFKBP13 in vivo and in vitro through yeast two-hybrid analysis and bimolecular fluorescence complementation (BiFC) assays. Moreover, quantitative real-time PCR analysis showed that when the expression of BcHTT4 was silenced in ‘Suzhouqing’, the expression of BcFKBP13 also decreased significantly. Our findings reveal that BcHTT4 is involved in the branching mechanism and interacts with immunophilin BcFKBP13 in NHCC.
Essential Oil Composition and Micromorphological Traits of Satureja montana L., S. subspicata Bartel ex Vis., and S. kitaibelii Wierzb. Ex Heuff. Plant Organs
Authors: Dodoš Tanja , Janković Smiljana , Marin Petar D. , Rajčević Nemanja
Published: March 2021

The essential oil (EO) composition of Satureja plants is highly variable. Recent studies suggest that there is an even difference in the EO composition from different plant organs within the same plant. This study aims to examine the chemical profile of EOs and the micromorphological characteristics of different organs of three Satureja species. The relationship between the number of glandular trichomes and EOs profile and relative yield is also investigated. Individuals from five populations were visualized using a scanning electron microscope, while EOs of leaves, calyces, corollas, and whole aerial parts were isolated using simultaneous distillation and extraction and analyzed using gas chromatography/mass spectrometry. Three types of glandular trichomes were detected. Peltate trichomes were present on all plant organs of studied species, while two types of capitate trichomes show different organ and species preferences. The EOs profiles differed across the plant parts, but showed a species specific composition. Univariate and multivariate statistics were used to show a correlation between the peltate trichomes and EO yield, and chemophenetic significance of EO profiles.
Sustainable Myrcene-Based Elastomers via a Convenient Anionic Polymerization
Authors: Lamparelli David Hermann , Kleybolte Magdalena Maria , Winnacker Malte , Capacchione Carmine
Published: March 2021

Soluble heterocomplexes consisting of sodium hydride in combination with trialkylaluminum derivatives have been used as anionic initiating systems at 100 °C in toluene for convenient homo-, co- and ter-polymerization of myrcene with styrene and isoprene. In this way it has been possible to obtain elastomeric materials in a wide range of compositions with interesting thermal profiles and different polymeric architectures by simply modulating the alimentation feed and the (monomers)/(initiator systems) ratio. Especially, a complete study of the myrcene-styrene copolymers (PMS) was carried out, highlighting their tapered microstructures with high molecular weights (up to 159.8 KDa) and a single glass transition temperature. For PMS copolymer reactivity ratios, rmyr = 0.12 ± 0.003 and rsty = 3.18 ± 0.65 and rmyr = 0.10 ± 0.004 and rsty = 3.32 ± 0.68 were determined according to the Kelen–Tudos (KT) and extended Kelen–Tudos (exKT) methods, respectively. Finally, this study showed an easy accessible approach for the production of various elastomers by anionic copolymerization of renewable terpenes, such as myrcene, with commodities.
Thermal Decomposition and Combustion of Microwave Pre-Treated Biomass Pellets
Authors: Goldšteins Linards , Valdmanis Raimonds , Zaķe Maija , Arshanitsa Alexandr , Andersone Anna
Published: March 2021

The objective of the study was to investigate a more effective use of commercially available biomass pellets (wheat straw, wood, peat) using microwave pretreatment to improve heat production. Pellets were pretreated using the originally designed microwave torrefaction device. The effects of microwave (mw) pretreatment were quantified, providing measurements of the weight loss and elemental composition of pellets and estimating the effect of mw pretreatment on their porosity, surface area and calorific values at pretreatment temperatures of T = 448–553 K. Obtained results show that the highest structural variations and elemental composition during mw pretreatment were obtained for wheat straw pellets, with an increase in reactivity, a decreasing in the duration of the thermal decomposition by about 40% and an increase in the yield of combustible volatiles. Increased reactivity of pretreated pellets enhanced the ignition and burnout of volatiles, decreasing the duration of the burnout of pretreated wheat straw, wood and peat pellets by 40%, 24% and 9%, respectively, and increasing the peak and average values of the flame temperature, heat output, and produced heat energy by 40–50%, with a correlating increase of combustion efficiency and the mass fraction of carbon-neutral CO2 emission. Thus, the applicability of microwave pretreatment for the control and improvement of heat production was confirmed.
Advancing Plastic Recycling by Wet-Mechanical Processing of Mixed Waste Fractions
Authors: Schwabl Daniel , Bauer Markus , Lehner Markus
Published: March 2021

In this paper, an arc was drawn over ten years of research activities from three chairs of the Montanuniversitaet Leoben, as well as industrial partners. The superior objective of this research effort was to develop a wet-mechanical process for the recovery of polyolefin concentrates (90 wt% polyolefins) from mixed waste fraction for use in chemical recycling and to advance this new technology to commercial maturity. As a bridge technology, it would close the gap between state-of-the-art dry processing of mixed plastic waste materials and chemical plastic recycling via thermo-chemical conversion. The methods used were mainly tested in a lab-scale plant with a throughput capacity of 50 to 200 kg/h depending on the bulk density of the used feedstock. Further studies for the treatment and usage of the main products and by-products, as well as chemical analyses of them, were completed during the investigation. Within these series of tests, polyolefin concentrates, which satisfied the requirements for chemical recycling, could be recovered. With these data, a concept for an industrial pilot plant was developed and evaluated from an economic point of view. According to this evaluation, the realization of such an industrial pilot plant can be recommended.
Statistical Optimization of Alkali Pretreatment to Improve Sugars Recovery from Spent Coffee Grounds and Utilization in Lactic Acid Fermentation
Authors: Lee Kang Hyun , Jang Ye Won , Lee Jeongho , Kim Seunghee , Park Chulhwan , Yoo Hah Young
Published: March 2021

Biorefinery, which utilizes carbon-neutral biomass as a resource, is attracting attention as a significant alternative in a modern society confronted with climate change. In this study, spent coffee grounds (SCGs) were used as the feedstock for lactic acid fermentation. In order to improve sugar conversion, alkali pretreatment was optimized by a statistical method, namely response surface methodology (RSM). The optimum conditions for the alkali pretreatment of SCGs were determined as follows: 75 °C, 3% potassium hydroxide (KOH) and a time of 2.8 h. The optimum conditions for enzymatic hydrolysis of pretreated SCGs were determined as follows: enzyme complex loading of 30-unit cellulase, 15-unit cellobiase and 50-unit mannanase per g biomass and a reaction time of 96 h. SCG hydrolysates were used as the carbon source for Lactobacillus cultivation, and the conversions of lactic acid by L. brevis ATCC 8287 and L. parabuchneri ATCC 49374 were 40.1% and 55.8%, respectively. Finally, the maximum lactic acid production by L. parabuchneri ATCC 49374 was estimated to be 101.2 g based on 1000 g of SCGs through the optimization of alkali pretreatment and enzymatic hydrolysis.
Modeling the Influence of Temperature, Light Intensity and Oxygen Concentration on Microalgal Growth Rate
Authors: López Muñoz Ignacio , Bernard Olivier
Published: March 2021

Dissolved oxygen plays a key role in microalgal growth at high density. This effect was so far rarely quantified. Here we propose a new model to represent the combined effect of light, oxygen concentration and temperature (LOT-model) on microalgae growth. The LOT-model introduces oxygen concentration in order to represent the oxidative stress affecting the cultures, adding a toxicity term in the expression of the net growth rate. The model was validated with experimental data for several species such as Chlorella minutissima, Chlorella vulgaris, Dunaliella salina, Isochrysis galbana. It successfully predicted experimental records with an average error lower than 5.5%. The model was also validated using dynamical data where oxygen concentration varies. It highlights a strong impact of oxygen concentration on productivity, depending on temperature. The model quantifies the sensitivity to oxidative stress of different species and shows, for example, that Dunaliella salina is much less affected than Chlorella vulgaris by oxidative stress. The modeling approach can support an optimization strategy to improve productivity, especially for managing high oxygen levels.
Liturgical and Pastoral Activity as a Crime in Soviet Ukraine: The Case of Greek Catholic Priest, Roman Bakhtalovskyy, CSsR (1897–1985)
Authors: Oliynyk Andriy
Published: March 2021

This article examines the liturgical life of the “Underground” Greek Catholic Church through the example of the life of the prominent priest, writer and poet, Roman Bakhtalovskyy, CSsR. After 1946, the Soviet government in Ukraine prohibited the activity of this Church. Therefore, the sacramental activity of Greek Catholic priests was performed in complete secrecy until 1989. The analysis of archival criminal cases is an important source of research during this difficult period for the Church, in which pastoral activity was a pretext for arrest and imprisonment, and sacred objects were seized during searches. This article analyzes in detail the criminal case of Fr. Roman Bakhtalovskyy, which was opened by special services in 1968–1969. The confiscated objects of analysis provide valuable information about the liturgical activity, devotional practices and spirituality of that period of persecution of Catholics in Soviet Ukraine which coincided with the reforms of the Second Vatican Council and their implementation elsewhere.
Traversing a Tightrope between Ecumenism and Exclusivism: The Intertwined History of South Africa’s Dutch Reformed Church and the Church of Central Africa Presbyterian in Nyasaland (Malawi)
Authors: Müller Retief
Published: March 2021

During the first few decades of the 20th century, the Nkhoma mission of the Dutch Reformed Church of South Africa became involved in an ecumenical venture that was initiated by the Church of Scotland’s Blantyre mission, and the Free Church of Scotland’s Livingstonia mission in central Africa. Geographically sandwiched between these two Scots missions in Nyasaland (presently Malawi) was Nkhoma in the central region of the country. During a period of history when the DRC in South Africa had begun to regressively disengage from ecumenical entanglements in order to focus on its developing discourse of Afrikaner Christian nationalism, this venture in ecumenism by one of its foreign missions was a remarkable anomaly. Yet, as this article illustrates, the ecumenical project as finalized at a conference in 1924 was characterized by controversy and nearly became derailed as a result of the intransigence of white DRC missionaries on the subject of eating together with black colleagues at a communal table. Negotiations proceeded and somehow ended in church unity despite the DRC’s missionaries’ objection to communal eating. After the merger of the synods of Blantyre, Nkhoma and Livingstonia into the unified CCAP, distinct regional differences remained, long after the colonial missionaries departed. In terms of its theological predisposition, especially on the hierarchy of social relations, the Nkhoma synod remains much more conservative than both of its neighboring synods in the CCAP to the south and north. Race is no longer a matter of division. More recently, it has been gender, and especially the issue of women’s ordination to ministry, which has been affirmed by both Blantyre and Livingstonia, but resisted by the Nkhoma synod. Back in South Africa, these events similarly had an impact on church history and theological debate, but in a completely different direction. As the theology of Afrikaner Christian nationalism and eventually apartheid came into positions of power in the 1940s, the DRC’s Nkhoma mission in Malawi found itself in a position of vulnerability and suspicion. The very fact of its participation in an ecumenical project involving ‘liberal’ Scots in the formation of an indigenous black church was an intolerable digression from the normative separatism that was the hallmark of the DRC under apartheid. Hence, this article focuses on the variegated entanglements of Reformed Church history, mission history, theology and politics in two different 20th-century African contexts, Malawi and South Africa.
Effectiveness of Nature-Based Solutions on Pluvial Flood Hazard Mitigation: The Case Study of the City of Eindhoven (The Netherlands)
Authors: Costa Sandra , Peters Rik , Martins Ricardo , Postmes Luuk , Keizer Jan Jacob , Roebeling Peter
Published: March 2021

Urbanization leads to changes in the surface cover that alter the hydrological cycle of cities, particularly by increasing the impervious area and, thereby, reducing the interception, storage and infiltration capacity of rainwater. Nature-based solutions (NBS) can contribute to flood risk mitigation in urbanized areas by restoring hydrological functions. However, the effects of NBS on flood risk mitigation are complex and can differ substantially with the type of the NBS. Therefore, the effectiveness of NBS at the urban catchment scale is still subject to much debate, especially at the scale of urban catchments. In this study, the effects of different NBS on urban flood mitigation were evaluated for the city of Eindhoven in The Netherlands, as it has a history of urban flood events. To this end, various NBS scenarios were defined by municipal stakeholders and their impacts modelled with the numerical model Infoworks ICM. This was done for design storms with short, medium and long return periods (5, 10 and 100 years). Overall, the simulated NBS were effective in flood risk mitigation, reducing the flooded area as well as flood depth. The effectiveness of the individual NBS scenarios, however, depended strongly on the location and extension of the NBS, as well as on storm intensity. The effectiveness tended to increase with the increase in NBS surface area, while it tended to decrease with increasing storm intensity and, hence, return period. The NBS solution increasing street water storage was revealed to be more effective than those involving green car parks and green roofs. This study showed that numerical flooding models can be useful tools to assess the effects of NBS to reduce flood extent, water depth and/or velocity, providing insights that can support city planners to design and compare alternative strategies and plans for urban flood risk mitigation.
Cobot User Frame Calibration: Evaluation and Comparison between Positioning Repeatability Performances Achieved by Traditional and Vision-Based Methods
Authors: Pagani Roberto , Nuzzi Cristina , Ghidelli Marco , Borboni Alberto , Lancini Matteo , Legnani Giovanni
Published: March 2021

Since cobots are designed to be flexible, they are frequently repositioned to change the production line according to the needs; hence, their working area (user frame) needs to be often calibrated. Therefore, it is important to adopt a fast and intuitive user frame calibration method that allows even non-expert users to perform the procedure effectively, reducing the possible mistakes that may arise in such contexts. The aim of this work was to quantitatively assess the performance of different user frame calibration procedures in terms of accuracy, complexity, and calibration time, to allow a reliable choice of which calibration method to adopt and the number of calibration points to use, given the requirements of the specific application. This has been done by first analyzing the performances of a Rethink Robotics Sawyer robot built-in user frame calibration method (Robot Positioning System, RPS) based on the analysis of a fiducial marker distortion obtained from the image acquired by the wrist camera. This resulted in a quantitative analysis of the limitations of this approach that only computes local calibration planes, highlighting the reduction of performances observed. Hence, the analysis focused on the comparison between two traditional calibration methods involving rigid markers to determine the best number of calibration points to adopt to achieve good repeatability performances. The analysis shows that, among the three methods, the RPS one resulted in very poor repeatability performances (1.42 mm), while the three and five points calibration methods achieve lower values (0.33 mm and 0.12 mm, respectively) which are closer to the reference repeatability (0.08 mm). Moreover, comparing the overall calibration times achieved by the three methods, it is shown that, incrementing the number of calibration points to more than five, it is not suggested since it could lead to a plateau in the performances, while increasing the overall calibration time.
On the Impact of Gravity Compensation on Reinforcement Learning in Goal-Reaching Tasks for Robotic Manipulators
Authors: Fugal Jonathan , Bae Jihye , Poonawala Hasan A.
Published: March 2021

Advances in machine learning technologies in recent years have facilitated developments in autonomous robotic systems. Designing these autonomous systems typically requires manually specified models of the robotic system and world when using classical control-based strategies, or time consuming and computationally expensive data-driven training when using learning-based strategies. Combination of classical control and learning-based strategies may mitigate both requirements. However, the performance of the combined control system is not obvious given that there are two separate controllers. This paper focuses on one such combination, which uses gravity-compensation together with reinforcement learning (RL). We present a study of the effects of gravity compensation on the performance of two reinforcement learning algorithms when solving reaching tasks using a simulated seven-degree-of-freedom robotic arm. The results of our study demonstrate that gravity compensation coupled with RL can reduce the training required in reaching tasks involving elevated target locations, but not all target locations.
The Temporal Variation of Optical Depth in the Candidate Landing Area of China’s Mars Mission (Tianwen-1)
Authors: Tang Zhencheng , Liu Jianjun , Wang Xing , Ren Xin , Yan Wei , Chen Wangli
Published: March 2021

The atmospheric dust is an important factor in the evolution of the Martian climate and has a major impact on the scientific exploration of the Martian lander or rover and its payload. This paper used remote sensing images to calculate atmospheric optical depth that characterizes the spatial distribution of the atmospheric dust of Mars. The optical depth calculated by the images of the High Resolution Imaging Science Experiment (HiRISE) in the inspection area of the Spirit rover had a similar temporal variation to the optical depth directly measured by the Spirit rover from the sunlight decay. We also used the HiRISE images to acquire the seasonal variation of optical depths in the candidate landing area of China’s Mars Mission (Tianwen-1). The results have shown that the seasonal pattern of the optical depth in the candidate landing area is consistent with the dust storm sequences in this area. After Tianwen-1 enters the orbit around Mars, the images collected by the Moderate Resolution Imaging Camera (MoRIC), and the High Resolution Imaging Camera (HiRIC) can be used to study the atmospheric optical depth in the candidate landing area, providing reference for the safe landing and operation of the lander and rover.
The Decrease in Lake Numbers and Areas in Central Asia Investigated Using a Landsat-Derived Water Dataset
Authors: Che Xianghong , Feng Min , Sun Qing , Sexton Joseph O. , Channan Saurabh , Liu Jiping
Published: March 2021

Although Central Asia has a strong continental climate with a constant moisture deficit and low relative humidity, it is covered by thousands of lakes that are critical to the sustainability of ecosystems and human welfare in the region. Vulnerability to climate change and anthropogenic activities have contributed to dramatic inter-annual and seasonal changes of the lakes. In this study, we explored the high spatio–temporal dynamics of the lakes of Central Asia using the terraPulse™ monthly Landsat-derived surface water extent dataset from 2000 to 2015 and the HydroLAKES dataset. The results identified 9493 lakes and significant linear decreasing trends were identified for both the number (rate: −85 lakes/year, R2: 0.69) and area (rate: −1314.1 km2/year, R2: 0.84) of the lakes in Central Asia between 2000 and 2015. The decrease rate in lake area accounted for 1.41% of the total lake area. About 75% of the investigated lakes (7142 lakes), mainly located in the Kazakh steppe (especially in the north) and the Badghyz and Karabil semi-desert terrestrial ecological zones, experienced a decrease in the water area. Lakes with increasing water area were mainly distributed in the Northern Tibetan Plateau–Kunlun Mountains alpine desert and Qaidam Basin semi-desert zones in the east-south corner of Central Asia. The possible driving factors of lake decreases in Central Asia were explored for the Aral Sea and Tengiz Lake on yearly and monthly time scales. The Aral Sea showed the greatest decrease in the summer months because of increased evaporation and massive irrigation, while the largest decrease for Tengiz Lake was observed in early spring and was linked to decreasing snowmelt.
Remote Soil Moisture Measurement from Drone-Borne Reflectance Spectroscopy: Applications to Hydroperiod Measurement in Desert Playas
Authors: Levy Joseph S. , Johnson Jessica T. E.
Published: March 2021

The extent, timing, and magnitude of soil moisture in wetlands (the hydropattern) is a primary physical control on biogeochemical processes in desert environments. However, determining playa hydropatterns is challenged by the remoteness of desert basin sites and by the difficulty in determining soil moisture from remotely sensed data at fine spatial and temporal scales (hundreds of meters to kilometers, and hours to days). Therefore, we developed a new, reflectance-based soil moisture index (continuum-removed water index, or CRWI) that can be determined via hyperspectral imaging from drone-borne platforms. We compared its efficacy at remotely determining soil moisture content to existing hyperspectral and multispectral soil moisture indices. CRWI varies linearly with in situ soil moisture content (R2 = 0.89, p < 0.001) and is comparatively insensitive to soil clay content (R2 = 0.4, p = 0.01), soil salinity (R2 = 0.82, p < 0.001), and soil grain size distribution (R2 = 0.67, p < 0.001). CRWI is negatively correlated with clay content, indicating it is not sensitive to hydrated mineral absorption features. CRWI has stronger correlation with surface soil moisture than other hyperspectral and multispectral indices (R2 = 0.69, p < 0.001 for WISOIL at this site). Drone-borne reflectance measurements allow monitoring of soil moisture conditions at the Alvord Desert playa test site over hectare-scale soil plots at measurement cadences of minutes to hours. CRWI measurements can be used to determine surface soil moisture at a range of desert sites to inform management decisions and to better reveal ecosystem processes in water-limited environments.
Deriving Water Quality Parameters Using Sentinel-2 Imagery: A Case Study in the Sado Estuary, Portugal
Authors: Sent Giulia , Biguino Beatriz , Favareto Luciane , Cruz Joana , Sá Carolina , Dogliotti Ana Inés , Palma Carla , Brotas Vanda , Brito Ana C.
Published: March 2021

Monitoring water quality parameters and their ecological effects in transitional waters is usually performed through in situ sampling programs. These are expensive and time-consuming, and often do not represent the total area of interest. Remote sensing techniques offer enormous advantages by providing cost-effective systematic observations of a large water system. This study evaluates the potential of water quality monitoring using Sentinel-2 observations for the period 2018–2020 for the Sado estuary (Portugal), through an algorithm intercomparison exercise and time-series analysis of different water quality parameters (i.e., colored dissolved organic matter (CDOM), chlorophyll-a (Chl-a), suspended particulate matter (SPM), and turbidity). Results suggest that Sentinel-2 is useful for monitoring these parameters in a highly dynamic system, however, with challenges in retrieving accurate data for some of the variables, such as Chl-a. Spatio-temporal variability results were consistent with historical data, presenting the highest values of CDOM, Chl-a, SPM and turbidity during Spring and Summer. This work is the first study providing annual and seasonal coverage with high spatial resolution (10 m) for the Sado estuary, being a key contribution for the definition of effective monitoring programs. Moreover, the potential of remote sensing methodologies for continuous water quality monitoring in transitional systems under the scope of the European Water Framework Directive is briefly discussed.
Angle-of-Arrival Estimation Using Difference Beams in Localized Hybrid Arrays
Authors: Li Hang , Cheng Zhiqun
Published: March 2021

Angle-of-arrival (AoA) estimation in localized hybrid arrays suffers from phase ambiguity owing to its localized structure and vulnerability to noise. In this letter, we propose a novel phase shift design, allowing each subarray to exploit difference beam steering in two potential AoA directions. This enables the calibration of cross-correlations and an enhanced phase offset estimation between adjacent subarrays. We propose two unambiguous AoA estimation schemes based on the even and odd ratios of the number of antennas per subarray N to the number of different phase shifts per symbol K (i.e., N/K), respectively. The simulation results show that the proposed approach greatly improves the estimation accuracy as compared to the state of the art when the ratio N/K is even.
Intermuscular Coordination in the Power Clean Exercise: Comparison between Olympic Weightlifters and Untrained Individuals—A Preliminary Study
Authors: Santos Paulo D. G. , Vaz João R. , Correia Paulo F. , Valamatos Maria J. , Veloso António P. , Pezarat-Correia Pedro
Published: March 2021

Muscle coordination in human movement has been assessed through muscle synergy analysis. In sports science, this procedure has been mainly applied to the comparison between highly trained and unexperienced participants. However, the lack of knowledge regarding strength training exercises led us to study the differences in neural strategies to perform the power clean between weightlifters and untrained individuals. Synergies were extracted from electromyograms of 16 muscles of ten unexperienced participants and seven weightlifters. To evaluate differences, we determined the pairwise correlations for the synergy components and electromyographic profiles. While the shape of activation patterns presented strong correlations across participants of each group, the weightings of each muscle were more variable. The three extracted synergies were shifted in time with the unexperienced group anticipating synergy #1 (−2.46 ± 18.7%; p < 0.001) and #2 (−4.60 ± 5.71%; p < 0.001) and delaying synergy #3 (1.86 ± 17.39%; p = 0.01). Moreover, muscle vectors presented more inter-group variability, changing the composition of synergy #1 and #3. These results may indicate an adaptation in intermuscular coordination with training, and athletes in an initial phase of training should attempt to delay the hip extension (synergy #1), as well as the upper-limb flexion (synergy #2).
Lung Nodule Segmentation with a Region-Based Fast Marching Method
Authors: Savic Marko , Ma Yanhe , Ramponi Giovanni , Du Weiwei , Peng Yahui
Published: March 2021

When dealing with computed tomography volume data, the accurate segmentation of lung nodules is of great importance to lung cancer analysis and diagnosis, being a vital part of computer-aided diagnosis systems. However, due to the variety of lung nodules and the similarity of visual characteristics for nodules and their surroundings, robust segmentation of nodules becomes a challenging problem. A segmentation algorithm based on the fast marching method is proposed that separates the image into regions with similar features, which are then merged by combining regions growing with k-means. An evaluation was performed with two distinct methods (objective and subjective) that were applied on two different datasets, containing simulation data generated for this study and real patient data, respectively. The objective experimental results show that the proposed technique can accurately segment nodules, especially in solid cases, given the mean Dice scores of 0.933 and 0.901 for round and irregular nodules. For non-solid and cavitary nodules the performance dropped—0.799 and 0.614 mean Dice scores, respectively. The proposed method was compared to active contour models and to two modern deep learning networks. It reached better overall accuracy than active contour models, having comparable results to DBResNet but lesser accuracy than 3D-UNet. The results show promise for the proposed method in computer-aided diagnosis applications.
Rapid Fabrication of Renewable Carbon Fibres by Plasma Arc Discharge and Their Humidity Sensing Properties
Authors: Chen Yi , Fang Fang , Abbel Robert , Patel Meeta , Parker Kate
Published: March 2021

Submicron-sized carbon fibres have been attracting research interest due to their outstanding mechanical and electrical properties. However, the non-renewable resources and their complex fabrication processes limit the scalability and pose difficulties for the utilisation of these materials. Here, we investigate the use of plasma arc technology to convert renewable electrospun lignin fibres into a new kind of carbon fibre with a globular and porous microstructure. The influence of arc currents (up to 60 A) on the structural and morphological properties of as-prepared carbon fibres is discussed. Owing to the catalyst-free synthesis, high purity micro-structured carbon fibres with nanocrystalline graphitic domains are produced. Furthermore, the humidity sensing characteristics of the treated fibres at room temperature (23 °C) are demonstrated. Sensors produced from these carbon fibres exhibit good humidity response and repeatability in the range of 30% to 80% relative humidity (RH) and an excellent sensitivity (0.81/%RH) in the high RH regime (60–80%). These results demonstrate that the plasma arc technology has great potential for the development of sustainable, lignin-based carbon fibres for a broad range of application in electronics, sensors and energy storage.
Relay Positioning for Load-Balancing and Throughput Enhancement in Dual-Hop Relay Networks
Authors: Kim Byungkwan , Kim Taejoon
Published: March 2021

In a cellular communication system, deploying a relay station (RS) is an effective alternative to installing a new base station (BS). A dual-hop network enhances the throughput of mobile stations (MSs) located in shadow areas or at cell edges by installing RSs between BSs and MSs. Because additional radio resources should be allocated to the wireless link between BS and RS, a frame to be transmitted from BS is divided into an access zone (AZ) and a relay zone (RZ). BS and RS communicate with each other through the RZ, and they communicate with their registered MSs through an AZ. However, if too many MSs are registered with a certain BS or RS, MS overloading may cause performance degradation. To prevent such performance degradation, it is very important to find the proper positions for RSs to be deployed. In this paper, we propose a method for finding the sub-optimal RS deployment location for the purpose of load-balancing and throughput enhancement. The advantage of the proposed method is the efficiency in find the sub-optimal location of RSs and its reliable tradeoff between load-balancing throughput enhancement. Since the proposed scheme finds the proper position by adjusting the distance and angle of RSs, its computational complexity lower than other global optimization approach or learning-based approach. In addition, the proposed scheme is constituted with the two stages of load-balancing and throughput enhancement. These procedures result in the appropriate tradeoff between load-balancing and throughput enhancement. The simulation results support these advancements of the proposed scheme.
Evaluation of Thawing and Stress Restoration Method for Artificial Frozen Sandy Soils Using Sensors
Authors: Kim Jongchan , Lee Jong-Sub , Arnold Cody , Kim Sang Yeob
Published: March 2021

Undisturbed frozen samples can be efficiently obtained using the artificial ground freezing method. Thereafter, the restoration of in situ conditions, such as stress and density after thawing, is critical for laboratory testing. This study aims to experimentally explore the effects of thawing and the in situ stress restoration process on the geomechanical properties of sandy soils. Specimens were prepared at a relative density of 60% and frozen at −20 °C under the vertical stress of 100 kPa. After freezing, the specimens placed in the triaxial cell underwent thawing and consolidation phases with various drainage and confining stress conditions, followed by the shear phase. The elastic wave signals and axial deformation were measured during the entire protocol; the shear strength was evaluated from the triaxial compression test. Monotonic and cyclic simple shear tests were conducted to determine the packing density effect on liquefaction resistance. The results show that axial deformation, stiffness, and strength are minimized for a specimen undergoing drained thawing, restoring the initial stress during the consolidation phase, and that denser specimens are less susceptible to liquefaction. Results highlight that the thawing and stress restoration process should be considered to prevent the overestimation of stiffness, strength, and liquefaction resistance of sandy soils.
Automatic Identification of Tool Wear Based on Thermography and a Convolutional Neural Network during the Turning Process
Authors: Brili Nika , Ficko Mirko , Klančnik Simon
Published: March 2021

This article presents a control system for a cutting tool condition supervision, which recognises tool wear automatically during turning. We used an infrared camera for process control, which—unlike common cameras—captures the thermographic state, in addition to the visual state of the process. Despite challenging environmental conditions (e.g., hot chips) we protected the camera and placed it right up to the cutting knife, so that machining could be observed closely. During the experiment constant cutting conditions were set for the dry machining of workpiece (low alloy carbon steel 1.7225 or 42CrMo4). To build a dataset of over 9000 images, we machined on a lathe with tool inserts of different wear levels. Using a convolutional neural network (CNN), we developed a model for tool wear and tool damage prediction. It determines the state of a cutting tool automatically (none, low, medium, high wear level), based on thermographic process data. The accuracy of classification was 99.55%, which affirms the adequacy of the proposed method. Such a system enables immediate action in the case of cutting tool wear or breakage, regardless of the operator’s knowledge and competence.
Validation of an RP-HPLC Method for the Determination of Asenapine Maleate in Dissolution Media and Application to Study In Vitro Release from Co-Crystals
Authors: Al-Nimry Suhair S. , Khanfar Mai S.
Published: March 2021

Asenapine maleate is an antipsychotic drug that is indicated in the treatment of schizophrenia and bipolar disorders. It has low aqueous solubility and high permeability (Class II drug) and undergoes an extensive first pass effect. These problems result in low oral bioavailability (<2%). To enhance its solubility/dissolution rate and hence bioavailability, co-crystals using different co-formers in different ratios were prepared and evaluated. To study the in vitro dissolution of the drug from these co-crystals into phosphate buffer (pH 6.8), an RP-HPLC method was developed and validated according to the ICH Q2R1 guidelines. The method was linear in the range 0.1–14 µg/mL (R > 0.9998) and accurate and precise. An ANOVA test indicated that calibration curves run on different days did not differ significantly. It was sensitive (lower limit of quantitation (LLOQ) = 25.03 ng/mL), specific (the co-formers did not interfere with the determination of the drug), and robust to small changes in the mobile phase (pH, composition, and flow rate). The in vitro release of asenapine maleate from the co-crystals and the physical mixture was much enhanced when compared to the in vitro dissolution of the unprocessed drug. In conclusion, the developed and validated RP-HPLC method met the acceptance criteria and was applied successfully in evaluating the in vitro release of the drug.
Designing the Participation on Local Development Planning: From Literature Review to Adaptive Framework for Practice
Authors: Hrivnák Michal , Moritz Peter , Melichová Katarína , Roháčiková Oľga , Pospišová Lucia
Published: March 2021

This exploratory review of the literature provides a comprehensive overview of the settings that are available to the planner when managing participatory strategic planning of spatial socio-economic development on the local level. We contextualize individual potential configurations of participation in local development planning practice, documented in a number of case studies from different parts of the world, in order to reflect the multidimensionality of the participatory planning process. These reflections are used to build a participation plan model, which aimed to help local planners, especially local governments, to optimize the participation of local stakeholders, according to the specifics of the local environment. The paper evaluates the options of planners to manage the participation from perspective of the organization of participation, the determination of its scope, selection of stakeholders, methods and techniques of communication, decision-making and visualization, as well as the deployment of resources, or the possibility of promotion and dissemination of information. As a practical implication of this review, we compose a participation matrix, which is intended to be an auxiliary tool for planners to establish own locally-specific participation plans and that can serve as tool for education, or life-long learning of planners.
Youth’s Physical Activity and Fitness from a Rural Environment of an Azores Island
Authors: Gouveia João Pedro , Forte Pedro , Coelho Eduarda
Published: March 2021

This study aimed to characterize and compare physical activity (PA) and fitness levels by sex in 109 students of a rural environment. The participants were between 15 and 20 years old, from the Santa Maria High School in the Azores’ Santa Maria island. PA levels were assessed by International Physical Activity Questionnaire (IPAQ)-short form. The physical fitness was evaluated by the Fitnessgram battery tests. The sample of this study were physically active, 67.9% were classified with high and moderate PA levels. Regarding the sex comparisons, no significant differences between PA levels were founded. However, males presented higher values of vigorous physical activity, whereas females spent more time in moderate activity, such as walking. Moreover, females had more time in sitting positions during the week and weekend. Regarding the physical fitness levels, males presented significantly higher performances in the upper strength (p < 0.001) and aerobic capacity tests (p < 0.001), whereas females showed higher values in the sit and reach test (p < 0.001), in the trunk lift test (p < 0.005), and in the fat mass values (p < 0.001). It seems reasonable to assume that there is a sociodemographic influence on the PA and physical fitness levels in our sample. We may speculate that rural life provides more opportunities for youth for being physically active than urban life. No differences were founded between sexes for physical activity. However, differences were found between sex for strength, flexibility, cardiorespiratory fitness, and body composition. That might be explained by the biological differences and the type of physical activity habits that each sex use to have in rural environmental.
Impact of Incentive Policies and Other Socio-Economic Factors on Electric Vehicle Market Share: A Panel Data Analysis from the 20 Countries
Authors: Xue Chenlei , Zhou Huaguo , Wu Qunqi , Wu Xueying , Xu Xingbo
Published: March 2021

Under the strong support of policies and incentives, the global electric vehicle (EV) market has been developing rapidly. However, in the context of the overall EV market boom, the promotion policies and incentives for consumers to adopt EVs differ from country to country. It is worth exploring the key factors that affect market share and adoption of EVs, such as incentives, policies, and additional socio-economic factors. The data on EV market share and information on policies and incentives in 20 countries were collected from the published reports and online resources from 2015 to 2019. Random effects model analysis was conducted to explore the effect of various factors on EV market share. The innovation of this article is to combine incentive policies with socio-economic factors and use panel data to analyze the actual adoption behavior of the global EV market. Results show that the tax reduction policy, charger density, and income have significantly positive effects on the penetration of EVs. Thus, it suggested that government should still maintain tax incentives and focus on the deployment of charging infrastructure. Household income, as a socio-economic factor, also plays an important role in the adoption of EVs. This will help policymakers adjust and improve policy emphasis to promote the adoption of EVs.
Socio-Spatial Aspects of Shrinking Municipalities: A Case Study of the Post-Communist Region of North-East Poland
Authors: Kocur-Bera Katarzyna , Szuniewicz Karol
Published: March 2021

Urban shrinkage has become a common feature for a growing number of European cities and urban regions. Cities in Europe have lost populations during the previous few decades, many of them in the post-communist countries. A similar phenomenon has been observed in smaller units: municipalities and villages. Shrinking towns/municipalities/villages grapple with insufficiently used housing infrastructure, a decrease in labor force, investment and in the number of jobs. This analysis examines the socio-spatial factors present in municipalities in the north-east of Poland, which are expected to experience the greatest population decrease by 2030. The study focused mainly on determinants with the greatest impact on the good life standards. It also sought to answer why the population growth forecasts for these units are so unpromising. The findings have shown that the majority of determinants adopted in the conceptual model describing the good life standards are below the reference values. The applied taxonomic measure of good life standards (TMGL) method allowed for identifying five municipality clusters representing “different speeds” at which these forecasts are fulfilled. Two clusters have dominant determinants in five criteria and three clusters, in two criteria adopted in the conceptual model. The findings indicate that approx. 35% of the municipalities under analysis have a chance for stabilization of the population size, provided local stakeholders take some targeted actions.
Delineating the Urban Areas of a Cross-Boundary City with Open-Access Data: Guangzhou–Foshan, South China
Authors: Ban Pengfei , Zhan Wei , Yuan Qifeng , Li Xiaojian
Published: March 2021

Cities defined mainly from the administrative aspect can create impact and problems especially in the case of China. However, only a few researchers from China have attempted to identify urban areas from the morphology dimension. In addition, previous studies have been mostly based on the national and regional scales or a single prefecture city and have completely ignored cross-boundary cities. Defining urban areas on the basis of a single data type also has limitations. To address these problems, this study integrates point of interest and nighttime light data, applies the breaking point analysis method to determine the physical geographic scope of the Guangzhou–Foshan cross-border city, and then compares this city with Beijing and Shanghai. Results show that Guangzhou–Foshan comprises one core urban area and six suburban counties, among which the core urban area extends across the administrative boundaries of Guangzhou and Foshan. The urban area and average urban radius of Guangzhou–Foshan are larger than those of Beijing and Shanghai, and this finding contradicts the city size measurements based on the administrative division system of China and those published on traditional official statistical yearbooks. In terms of urban density value, Shanghai has the steepest profile followed by Guangzhou–Foshan and Beijing, and the profile line of Guangzhou–Foshan has a bimodal shape.