bluuebunny/crossref_metadata_2025 huggingface dataset:
Current Challenges and Innovative Developments in Hydroxyapatite-Based Coatings on Metallic Materials for Bone Implantation: A Review
Authors: Beig Bilal , Liaqat Usman , Niazi Muhammad Farooq Khan , Douna Inamullah , Zahoor Muhammad , Niazi Muhammad Bilal Khan
Published: December 2020

Biomaterials are in use for the replacement and reconstruction of several tissues and organs as treatment and enhancement. Metallic, organic, and composites are some of the common materials currently in practice. Metallic materials contribute a big share of their mechanical strength and resistance to corrosion properties, while organic polymeric materials stand high due to their biocompatibility, biodegradability, and natural availability. To enhance the biocompatibility of these metals and alloys, coatings are frequently applied. Organic polymeric materials and ceramics are extensively utilized for this purpose due to their outstanding characteristics of biocompatibility and biodegradability. Hydroxyapatite (HAp) is the material from the ceramic class which is an ultimate candidate for coating on these metals for biomedical applications. HAp possesses similar chemical and structural characteristics to normal human bone. Due to the bioactivity and biocompatibility of HAp, it is used for bone implants for regenerating bone tissues. This review covers an extensive study of the development of HAp coatings specifically for the orthopaedic applications that include different coating techniques and the process parameters of these coating techniques. Additionally, the future direction and challenges have been also discussed briefly in this review, including the coating of HAp in combination with other calcium magnesium phosphates that occur naturally in human bone.
4-(Trifluoromethoxy)phenyl-Containing Polymers as Promising Anodic Materials for Electrochromic Devices
Authors: Wang Wen-Hsin , Chang Jui-Cheng , Lee Pei-Ying , Lin Yuan-Chung , Wu Tzi-Yi
Published: December 2020

Three 4-(trifluoromethoxy)phenyl-based polydithienylpyrroles (PTTPP, P(TTPP-co-DTC), and P(TTPP-co-DTP)) were synthesized electrochemically and their electrochromic behaviors were characterized. The introduction of electron withdrawing trifluoromethoxy unit in the side chain of polydithienylpyrroles (PSNS) decreases the HOMO and LUMO energy levels of PSNS. PTTPP film displays three various colors (grayish-yellow at 0 V, grayish-blue at 1.0 V, and bluish-violet at 1.4 V) from reduced to oxidized states. The optical contrast of PTTPP, P(TTPP-co-DTC), and P(TTPP-co-DTP) electrodes are 24.5% at 1050 nm, 49.0% at 916 nm, and 53.8% at 1302 nm, respectively. The highest η of the PTTPP electrode is 379.64 cm2 C−1 at 1050 nm. Three ECDs based on PTTPP, P(TTPP-co-DTC), or P(TTPP-co-DTP) as anodic film and PProDOT-Et2 as cathodic film were fabricated. PTTPP/PProDOT-Et2 ECD showed high transmittance change (35.7% at 588 nm) and high η (890.96 cm2·C−1 at 588 nm). P(TTPP-co-DTC)/PProDOT-Et2 and P(TTPP-co-DTP)/PProDOT-Et2 ECDs showed high transmittance change, rapid response time, adequate open circuit memory, and good electrochemical redox stability. Based on these findings, this work provides novel insights for appropriate design of high transmittance change and high efficient multi-colored electrochromic polymers.
Effects of the Nitrogen Flow Ratio and Substrate Bias on the Mechanical Properties of W–N and W–Si–N Films
Authors: Chang Li-Chun , Sung Ming-Ching , Chu Li-Heng , Chen Yung-I
Published: December 2020

The reactive gas flow ratio and substrate bias voltage are crucial sputtering parameters for fabricating transition metal nitride films. In this study, W–N films were prepared using sputtering with nitrogen flow ratios (f) of 0.1–0.5. W–N and W–Si–N films were then prepared using an f level of 0.4 and substrate bias varying from 0 to −150 V by using sputtering and co-sputtering, respectively. The variations in phase structures, bonding characteristics, mechanical properties, and wear resistance of the W–N and W–Si–N films were investigated. The W–N films prepared with nitrogen flow ratios of 0.1–0.2, 0.3, and 0.4–0.5 displayed crystalline W, amorphous W–N, and crystalline W2N, respectively. The W–N films prepared using a nitrogen flow ratio of 0.4 and substrate bias voltages of −50 and −100 V exhibited favorable mechanical properties and high wear resistance. The mechanical properties of the amorphous W–Si–N films were not related to the magnitude of the substrate bias.
Particle Velocimetry, CFD, and the Role of Particle Sphericity in Cold Spray
Authors: Özdemir Ozan Çağatay , Conahan Joseph Mitchell , Müftü Sinan
Published: December 2020

Implementation of the cold spray (CS) technology in manufacturing and repair creates a demand for reliable quality control and process monitoring measures. In this regard, particle size and impact velocity are undoubtedly the most important control parameters in CS. Several in-flight measurement systems for particle velocimetry are now available commercially for CS. These systems provide great potential to be used as a diagnostic tool for validating CS system performance in industrial applications. However, post processing the velocimetry data is required in many instances for achieving a complete understanding of the particle flow field. In this study, particle velocimetry is used in conjunction with computational fluid dynamics (CFD) simulations to: (i) identify the physical factors that dictate the particle velocity and its variability; (ii) develop high fidelity CFD models to accurately predict particle flight parameters that cannot be measured by available experimental tools; and (iii) present the capabilities of state-of-the-art velocimeters as a reliable diagnostic tool for measuring the consistency and repeatability of CS systems in manufacturing settings. In-flight particle size, location, and velocity are measured using a commercially available velocimeter for aluminum and copper particles sprayed with supersonic nozzles using helium, nitrogen, and air by two high pressure CS systems. As a result of this work, particle sphericity was clearly identified to have strong effects on particle velocity and to be one of the main factors of the variability of particle velocity. Furthermore, methods for building a high-fidelity 3D-CFD model was presented. CFD models were validated using particle velocimetry and schlieren imaging. Finally, particle velocimetry is shown to be a valid diagnostics tool for CS with systems capable of measuring in-flight particle velocities along with particle sizes. This article also outlines steps necessary for conducting cold spray process diagnostics repeatably and reliably.
Current Understanding of Bias-Temperature Instabilities in GaN MIS Transistors for Power Switching Applications
Authors: Ťapajna Milan
Published: December 2020

GaN-based high-electron mobility transistors (HEMTs) have brought unprecedented performance in terms of power, frequency, and efficiency. Application of metal-insulator-semiconductor (MIS) gate structure has enabled further development of these devices by improving the gate leakage characteristics, gate controllability, and stability, and offered several approaches to achieve E-mode operation desired for switching devices. Yet, bias-temperature instabilities (BTI) in GaN MIS transistors represent one of the major concerns. This paper reviews BTI in D- and E-mode GaN MISHEMTs and fully recess-gate E-mode devices (MISFETs). Special attention is given to discussion of existing models describing the defects distribution in the GaN-based MIS gate structures as well as related trapping mechanisms responsible for threshold voltage instabilities. Selected technological approaches for improving the dielectric/III-N interfaces and techniques for BTI investigation in GaN MISHEMTs and MISFETs are also outlined.
Mueller Matrix Polarimetric Imaging Analysis of Optical Components for the Generation of Cylindrical Vector Beams
Authors: López-Morales Guadalupe , Sánchez-López María , Lizana Ángel , Moreno Ignacio , Campos Juan
Published: December 2020

In this work, we performed a Mueller matrix imaging analysis of two commercial optical components usually employed to generate and manipulate vector beams—a radial polarizer and a liquid-crystal q-plate. These two elements generate vector beams by different polarization mechanisms—polarizance and retardance, respectively. The quality of the vector beams relies on the quality of the device that generates them. Therefore, it is of interest to apply the well-established polarimetric imaging techniques to evaluate these optical components by identifying their spatial homogeneity in diattenuation, polarizance, depolarization, and retardance, as well as the spatial variation of the angles of polarizance and retardance vectors. For this purpose, we applied a customized imaging Mueller matrix polarimeter based on liquid-crystal retarders and a polarization camera. Experimental results were compared to the numerical simulations, considering the theoretical Mueller matrix. This kind of polarimetric characterization could be very helpful to the manufacturers and users of these devices.
Cheilospirura hamulosa in the Rock Partridge (Alectoris graeca saxatilis): Epidemiological Patterns and Prediction of Parasite Distribution in France
Authors: Fanelli Angela , Tizzani Paolo , Ferroglio Ezio , Belleau Eric
Published: December 2020

The rock partridge (Alectoris graeca saxatilis) is an alpine Galliform with high conservation value. Several factors, including parasitic helminths, play a role in population dynamics, and consequently in the conservation management of wild Galliformes. The aim of this study was to assess the epidemiological characteristics of Cheilospirura hamulosa (Nematoda, Acuarioidea) in the Rock partridge population in France. Machine learning modeling algorithms were applied to identify the environmental variables influencing parasite occurrence, and to map parasite presence probability. The present work is based on a long-term sampling (1987–2019) conducted in the French Alps. C. hamulosa was found with a prevalence (P) of 39% (Confidence Interval—CI 95%: 34–43), and mean intensity of 7.7 (7.8 sd). The highest prevalence (P: 67%, CI 95%: 54–80) was detected in the period 2005–2009. Latitude was the most important variable shaping the parasite distribution, followed by altitude, annual mean temperature, temperature seasonality, and the amount of precipitation of the coldest quarter. The area suitable for parasite presence included 73% of the French Alps. This work represents the first epidemiological surveillance on C. hamulosa infection in the rock partridge. It provides evidence of a high level of infection and identifies priority areas at higher infection risk, where a close monitoring of the rock partridge populations should be carried out.
Management Effectiveness Assessment for Ecuador’s National Parks
Authors: Negru Ciprian , Gaibor Isabel Domínguez , Hălălișan Aureliu-Florin , Popa Bogdan
Published: December 2020

Ecuador belongs to the group of 17 megadiverse countries on the planet, and the Ecuadorian national system of protected areas covers around 20% of the country’s territory. Despite some initiatives for protected areas management effectiveness evaluation, the information on this matter is scarce and a general overview is missing. In this context, this study aims at investigating problems faced by National Parks in Ecuador and developing a base level management effectiveness evaluation for possible comparative assessments in the future. Focusing on all 12 legally established National Parks, this study used the Management Effectiveness Tracking Tool (METT), an internationally consecrated methodology based on a scorecard questionnaire that includes six elements of management cycle: context, planning, inputs, processes, outputs and outcomes. The questionnaire was applied to Ecuadorian National Parks management teams through face-to-face interviews. The resulted overall management effectiveness indices are between 40.6% and 99.0%. The general condition of biodiversity value was considered as good in line with the legal status and National Parks design but topics related to budget allocation, tourism arrangements, communities and indigenous people received lower scores. The low enforcement emphasis is not necessarily the best way to improve management effectiveness; the identified issues should be addressed by including communities and indigenous people in the decision making and benefits sharing as well as strategic allocation of budgetary resources, with proper adaptation to Natural Parks’ specific conditions.
Multi-Modal Medical Image Fusion Based on FusionNet in YIQ Color Space
Authors: Guo Kai , Li Xiongfei , Zang Hongrui , Fan Tiehu
Published: December 2020

In order to obtain the physiological information and key features of source images to the maximum extent, improve the visual effect and clarity of the fused image, and reduce the computation, a multi-modal medical image fusion framework based on feature reuse is proposed. The framework consists of intuitive fuzzy processing (IFP), capture image details network (CIDN), fusion, and decoding. First, the membership function of the image is redefined to remove redundant features and obtain the image with complete features. Then, inspired by DenseNet, we proposed a new encoder to capture all the medical information features in the source image. In the fusion layer, we calculate the weight of each feature graph in the required fusion coefficient according to the trajectory of the feature graph. Finally, the filtered medical information is spliced and decoded to reproduce the required fusion image. In the encoding and image reconstruction networks, the mixed loss function of cross entropy and structural similarity is adopted to greatly reduce the information loss in image fusion. To assess performance, we conducted three sets of experiments on medical images of different grayscales and colors. Experimental results show that the proposed algorithm has advantages not only in detail and structure recognition but also in visual features and time complexity compared with other algorithms.
A Continuous-Time Random Walk Extension of the Gillis Model
Authors: Pozzoli Gaia , Radice Mattia , Onofri Manuele , Artuso Roberto
Published: December 2020

We consider a continuous-time random walk which is the generalization, by means of the introduction of waiting periods on sites, of the one-dimensional non-homogeneous random walk with a position-dependent drift known in the mathematical literature as Gillis random walk. This modified stochastic process allows to significantly change local, non-local and transport properties in the presence of heavy-tailed waiting-time distributions lacking the first moment: we provide here exact results concerning hitting times, first-time events, survival probabilities, occupation times, the moments spectrum and the statistics of records. Specifically, normal diffusion gives way to subdiffusion and we are witnessing the breaking of ergodicity. Furthermore we also test our theoretical predictions with numerical simulations.
Optimizing the Number of Fog Nodes for Finite Fog Radio Access Networks under Multi-Slope Path Loss Model
Authors: Bani-Bakr Alaa , Dimyati Kaharudin , Hindia MHD Nour , Wong Wei Ru , Al-Omari Ahmad , Sambo Yusuf Abdulrahman , Imran Muhammad Ali
Published: December 2020

Fog Radio Access Network (F-RAN) is a promising technology to address the bandwidth bottlenecks and network latency problems, by providing cloud-like services to the end nodes (ENs) at the edge of the network. The network latency can further be decreased by minimizing the transmission delay, which can be achieved by optimizing the number of Fog Nodes (FNs). In this context, we propose a stochastic geometry model to optimize the number of FNs in a finite F-RAN by exploiting the multi-slope path loss model (MS-PLM), which can more precisely characterize the path loss dependency on the propagation environment. The proposed approach shows that the optimum probability of being a FN is determined by the real root of a polynomial equation of a degree determined by the far-field path loss exponent (PLE) of the MS-PLM. The results analyze the impact of the path loss parameters and the number of deployed nodes on the optimum number of FNs. The results show that the optimum number of FNs is less than 7% of the total number of deployed nodes for all the considered scenarios. It also shows that optimizing the number of FNs achieves a significant reduction in the average transmission delay over the unoptimized scenarios.
Research on Hex Programmable Interconnect Points Test in Island-Style FPGA
Authors: Zhang Fan , Guo Chenguang , Zhang Shifeng , Chen Lei , Li Xuewu , Sun Huabo , Meng Yufeng , Chen Qiliang
Published: December 2020

With the decreasing size of manufacturing process, the scale of island-style field programmable gate array (FPGA) becomes larger, which leads to the increasing complexity of FPGA routing resources, especially hex programmable interconnect points (PIPs). Hex PIPs which span six tiles of the island-style FPGA have complex interconnect rules. Accordingly, research on complete hex PIPs test is rarely involved in the study of routing resources test. Therefore, this paper analyzes the hex PIPs architecture of the island-style FPGA, summarizes the interconnect rules of the hex PIPs mathematically in a two-dimensional coordinate system, and presents two proper test algorithms at the same time. The hex PIPs are divided into three directions, that is, horizontal, vertical, and oblique. According to the proposed coordinate equations, a cycle test structure in the horizontal and vertical directions and a test structure with partial-cascade patterns in the oblique direction are designed respectively. It is concluded that the proposed methods can achieve 100% fault coverage for the hex PIPs test in all directions, and the configuration number for hex lines test with the same methods is significantly decreased than previous researches.
Meta-Analysis on the Effectiveness of Virtual Reality Cognitive Training (VRCT) and Computer-Based Cognitive Training (CBCT) for Individuals with Mild Cognitive Impairment (MCI)
Authors: Hung Sarah Chui-wai , Ho Annie Yin-ni , Lai Idy Hiu-wai , Lee Carol Sze-wing , Pong Angela Shuk-kwan , Lai Frank Ho-yin
Published: December 2020

This meta-analysis aims to assess the effectiveness of virtual reality cognitive training (VRCT) and conventional computer-based cognitive training (CBCT) in five specific cognitive domains (i.e., global cognitive function (GCF), memory (Mem), executive function (EF), language (Lang) and visuospatial skills (VS)) of individuals with mild cognitive impairment. A total of 320 studies were yielded from five electronic databases. Eighteen randomized controlled trials met the PRISMA criteria, with 10 related to VRCT and 8 related to CBCT. A random-effect model was used in determining the main effect of cognitive training in five specific cognitive domains. VRCT provided the largest effect size on VS and Lang while the smallest on EF. CBCT provided the largest effect size on Mem and Lang while the smallest on EF. VRCT and CBCT generate an opposite effect on VS. VRCT outweighs CBCT in treatment effectiveness of GCF, EF, Lang and VS. More immersive and interactive experiences in VRCT may help individuals with MCI better engage in real-life experiences, which supports skill generalization and reduces external distractions. CBCT tends to improve Mem but no definite conclusions can be made. Further investigation with more stringent research design and specific protocol are required to reach consensus about the optimum intervention regime.
A New Hybrid Ćuk DC-DC Converter with Coupled Inductors
Authors: Pop-Calimanu Ioana-Monica , Balint Maria , Lascu Dan
Published: December 2020

This paper proposes a new hybrid Ćuk-type converter employing two inductors built on the same core which can be successfully used in applications requiring an output voltage considering higher than the input one. With few components added, in the proposed converter the static conversion ratio can be easily extended becoming wider compared to the classical Ćuk topology. At the same duty cycle range the output voltage is higher than in the classical Ćuk converter. The output voltage remains with negative polarity and with a reduced ripple. An advantage of the new converter is given by its two degrees of freedom. A DC and AC analysis is carried out, device stresses are evaluated and a comparative analysis of the proposed hybrid Ćuk topology to other indirect converters has also been performed. All the equations necessary for designing the converter are provided. The simulations performed together with the practical experiments carried out, all results confirm that the theoretical considerations are correct and validate the features that the proposed converter can provide a higher static conversion ratio without operating at high duty cycles.
A Thermal Performance Detection Method for Building Envelope Based on 3D Model Generated by UAV Thermal Imagery
Authors: Zheng Haichao , Zhong Xue , Yan Junru , Zhao Lihua , Wang Xintian
Published: December 2020

The evaluation and renovation of existing building envelope has important practical significance for energy conservation and emission reduction in the field of architecture. With the development of digital cities, 3D models with rich temperature information can realize the comprehensive and accurate detection and evaluation of the existing building envelope. However, the 3D model reconstructed from thermal infrared images has only relative temperature distribution and no temperature value of each location, so it is impossible to quantify the extent of the defect from it. To solve this issue, this paper develops a method to establish a 3D point cloud model with temperature information at selected points. The proposed 3D model is generated based on the thermal infrared images acquired by an unmanned aerial vehicle (UAV) equipped with an infrared camera. In the generated 3D thermal infrared model, we can not only get the relative temperature distribution of the building’s full envelope structure, but also obtain the exact temperature value of any selected point. This method has been verified by field measurements and the result shows that the deviation is within 5 °C. In addition to temperature information, the generated 3D model also has spatial and depth information, which can reflect the appearance information and 3D structure of the monitoring target more realistically. Thus, by using this method, it is possible to achieve a comprehensive, accurate, and efficient on-site assessment of the building envelope in the urban area.
Suitability Pre-Assessment of in-Sewer Heat Recovery Sites Combining Energy and Wastewater Perspectives
Authors: Huber Franz , Neugebauer Georg , Ertl Thomas , Kretschmer Florian
Published: December 2020

In many countries around the world heating (and cooling) has been and will remain the biggest energy sector, but it is still widely dominated by fossil energy sources today. Wastewater as a source of renewable energy contains large amounts of heat and due to its place-bound localization in urban sewer systems it is usually also situated in very close distance to potential heat consumers. However, one has to keep in mind that heat extraction from wastewater might have undesired impacts on temperature-sensitive treatment processes in the related wastewater treatment plant (WWTP). To assess the potential impact of in-sewer heat recovery on inflow temperature, two different approaches are available today: a simple (but less significant) alligation alternate, or very accurate (but less practical) mathematical models. To close the gap between practicability and significance this article introduces a novel approach to pre-assess the suitability of in-sewer heat recovery sites based on little and easily available data considering energy- and wastewater-related perspectives. A case study application demonstrates the informative value and general usability of the approach. Consequently, the proposed procedure can provide guidance and a template for related investigations at any place in a conventional (combined or separated) sewer system.
Potential of Waste Biomass from the Sugar Industry as a Source of Furfural and Its Derivatives for Use as Fuel Additives in Poland
Authors: Modelska Magdalena , Binczarski Michal J. , Dziugan Piotr , Nowak Szymon , Romanowska-Duda Zdzisława , Sadowski Adam , Witońska Izabela A.
Published: December 2020

Poland is one of the leading producers of sugar from sugar beet in Europe. However, the production of sugar generates large amounts of lignocellulosic waste, in the form of beet pulp and leaves. Currently, this waste is not reutilized in the chemical industry, but is only used as food for farm animals. This paper assesses the potential of using bio-waste from the sugar industry as a raw material for the production of furfurals via acid hydrolysis. Further processing of furfural into derivatives such as furfuryl alcohol (FA) or tetrahydrofurfuryl alcohol (THFA) could increase the economic profitability of the initiative. Furfuryl alcohol can be used as a fuel additive in sugar factories. Tetrahydrofurfuryl alcohol can be used as a component in agricultural fertilizers, increasing the yield of sugar beet. This approach reduces the amount of post-production waste and brings the sugar industry closer to the concept of a circular economy.
A-Site Cation Engineering for Efficient Blue-Emissive Perovskite Light-Emitting Diodes
Authors: Park Jong Hyun , Jang Chung Hyeon , Jung Eui Dae , Lee Seungjin , Song Myoung Hoon , Lee Bo Ram
Published: December 2020

Metal halide perovskites have been investigated for the next-generation light-emitting materials because of their advantages such as high photoluminescence quantum yield (PLQY), excellent color purity, and facile color tunability. Recently, red- and green-emissive perovskite light-emitting diodes (PeLEDs) have shown an external quantum efficiency (EQE) of over 20%, whereas there is still room for improvement for blue emissive PeLEDs. By controlling the halide compositions of chloride (Cl−) and bromide (Br−), the bandgap of perovskites can be easily tuned for blue emission. However, halide segregation easily occurrs in the mixed-halide perovskite under light irradiation and LED operation because of poor phase stability. Here, we explore the effect of A-site cation engineering on the phase stability of the mixed-halide perovskites and find that a judicious selection of low dipole moment A cation (formamidinium or cesium) suppresses the halide segregation. This enables efficient bandgap tuning and electroluminescence stability for sky blue emissive PeLEDs over the current density of 15 mA/cm2.
Development and Techno-Economic Analysis of an Advanced Recycling Process for Photovoltaic Panels Enabling Polymer Separation and Recovery of Ag and Si
Authors: Rubino Antonio , Granata Giuseppe , Moscardini Emanuela , Baldassari Ludovica , Altimari Pietro , Toro Luigi , Pagnanelli Francesca
Published: December 2020

Photovoltaic panels were included in EU Directive as WEEE (Wastes of Electric and Electronic Equipment) requiring the implementation of dedicated collection schemes and end-of-life treatment ensuring targets in terms of recycling rate (80%) and recovery rate (85%). Photovoltaic panels are mainly made up of high-quality solar glass (70–90%), but also metals are present in the frames (Al), the cell (Si), and metallic contacts (Cu and Ag). According to the panel composition, about $72 per 100 kg of panels can be recovered by entirely recycling the panel metal content. The PhotoLife process for the treatment of end-of-life photovoltaic panels was demonstrated at pilot scale to recycle high value glass, Al and Cu scraps. A process upgrade is here reported allowing for polymer separation and Ag and Si recycling. By this advanced PhotoLife process, 82% recycling rate, 94% recovery rate, and 75% recoverable value were attained. Simulations demonstrated the economic feasibility of the process at processing capacity of 30,000 metric ton/y of end-of-life photovoltaic panels.
Assessment of the Lower Carboniferous-Devonian Aquifer as a Source of Geothermal Energy in the Silesian–Kraków Region (Poland)
Authors: Barbacki Antoni , Miecznik Maciej , Tomaszewska Barbara , Skrzypczak Robert
Published: December 2020

In view of the disastrous air pollution in the Silesian–Kraków region, reducing emissions from the combustion of conventional fuels is a particularly important issue. Geothermal energy is among the clean and renewable sources of heat that could be used to this end, for instance for recreation or space heating purposes. However, its use in the region is limited, mainly due to insufficient knowledge of the characteristics of the geothermal complexes present. Mesozoic complexes in the region have much smaller energy resources compared to the Polish Lowlands or Podhale, but Paleozoic ones, mainly the Lower Carboniferous and Devonian, offer realistic prospects for energy extraction. The aim of this study was to identify geothermal conditions within the Lower Carboniferous–Devonian complex, primarily in terms of using the waters present there for space heating purposes. The prospective zones identified and indicated during the research are only forecasts, and their actual utility can only be confirmed after new wells have been drilled to verify the actual conditions.
Numerical Study on Anisotropic Influence of Joint Spacing on Mechanical Behavior of Rock Mass Models under Uniaxial Compression
Authors: Chen Xin , Feng Zhongliang , Cheng Cheng
Published: December 2020

Mechanical properties of rock masses are dominated by the nonlinear response of joints and their arrangement. In this paper, combined influences of joint spacing (s) and joint inclination angle (β) on mechanical behavior of rock mass models with large open joints under uniaxial compression were investigated by PFC modeling. With a large amount of local measurement circles placed along the pre-defined measurement lines (ML), stresses and joint response parameters at different scales (the measurement circles, the MLs and the whole specimen) were defined and calculated. It was found that macroscopic behaviors of the jointed specimens, such as four types of deformation behaviors, four failure modes, strength, deformability modulus and ductility index, are dominated by nonlinear response of the joint system, especially the interaction between the joints and rock bridges. The joints may experience three stages, i.e., starting to close, closed and opening again. On the joint plane, the peak stresses of the rock bridges and those of the joints may not be reached at the same time; i.e., joint strength mobilization happens with the loss of the rock bridges’ resistance. The influence of s on specimen behavior is little for β = 90°, obvious for β = 0° or 30° and significant for β = 45° or 60°, and this can be related to their different microscopic damage mechanisms.
Image-Based River Water Level Estimation for Redundancy Information Using Deep Neural Network
Authors: Fleury Gabriela Rocha de Oliveira , do Nascimento Douglas Vieira , Galvão Filho Arlindo Rodrigues , Ribeiro Filipe de Souza Lima , de Carvalho Rafael Viana , Coelho Clarimar José
Published: December 2020

Monitoring and management of water levels has become an essential task in obtaining hydroelectric power. Activities such as water resources planning, supply basin management and flood forecasting are mediated and defined through its monitoring. Measurements, performed by sensors installed on the river facilities, are used for precisely information about water level estimations. Since weather conditions influence the results obtained by these sensors, it is necessary to have redundant approaches in order to maintain the high accuracy of the measured values. Staff gauge monitored by conventional cameras is a common redundancy method to keep track of the measurements. However, this method has low accuracy and is not reliable once it is monitored by human eyes. This work proposes to automate this process by using image processing methods of the staff gauge to measure and deep neural network to estimate the water level. To that end, three models of neural networks were compared: the residual networks (ResNet50), a MobileNetV2 and a proposed model of convolutional neural network (CNN). The results showed that ResNet50 and MobileNetV2 present inferior results compared to the proposed CNN.
Changes in Community Composition of Tropical Evergreen Forests during Succession in Ta Dung National Park, Central Highlands of Vietnam
Authors: Hai Nguyen Hong , Tan Nguyen Thanh , Bao Tran Quang , Petritan Any Mary , Mai Trinh Hien , Hien Cao Thi Thu , Anh Pham The , Hung Vu Tien , Petritan Ion Catalin
Published: December 2020

Degradation of tropical forests is a major driver of the global extinction crisis. A key question is understanding the role of evolution history during forest succession in the context of forest restoration for maintaining ecosystem function and stability. This study was conducted in a fragmented forest landscape in the central highlands of Vietnam. We sampled living trees with diameters at breast height of ≥6.0 cm in nineteen 0.25 ha plots to evaluate forest community structure changes over two early successional stages (<10 years and 10–20 years old) after abandonment and old-growth. We used both statistically metric and nonmetric analyses to examine correlations of community composition during successional stages and along elevational gradients. We found that (i) significant differences existed in the structural compositions between early successional forests and old-growth forests, but did not exist within early successional forests; (ii) the phylogenetic structure shifted from overdispersion to clustering with increasing successional ages; and (iii) above-ground biomass (AGB), representing ecosystem functioning, significantly increased from early-to-late successional stages, but did not correlate with phylogenetic diversity or elevation. Our results revealed that the forest community structure was strongly affected by degradation, particularly AGB and phylogenetic structure. These findings have clear implications for sustaining biodiversity persistence and ecosystem functioning in human-modified landscapes in the study region.
Molecular Cloning and Functional Characterization of the DELLA Gene Family in Liriodendron Hybrids
Authors: Liu Yang , Wang Pengkai , Yan Shan , Liu Xin , Lu Lu , Chen Xinying , Lu Ye , Hao Zhaodong , Shi Jisen , Chen Jinhui
Published: December 2020

DELLA proteins are key components of the gibberellins signal transduction pathway that play negative roles on promoting cell elongation and plant stature. However, the mechanisms underlying DELLA mediated growth inhibition in woody plant species are poorly understood. Here, we identified two LhDELLA genes including LhSLR-like (LhSLRL) and LhRGA from Liriodendron hybrids (Liriodendron chinense (Hemsl.) Sarg. × L. tulipifera L.), which is a horticultural tree with high-quality timber. Sequence analysis showed that LhSLRL and LhRGA possessed all typical conserved domains of DELLA proteins. Phylogenetic analysis showed that LhRGA was classified as the basal branch of DELLAs from species belonging to dicots. Interestingly, LhSLRL was a sister clade of DELLAs from the most ancient plant species such as bryophytes and ferns. Gene expression analysis showed that LhSLRL and LhRGA genes had the highest expression level in the stem. In addition, overexpression of LhSLRL decreased plant height and root length, increased branching and delayed flowering in Arabidopsis thaliana, while LhRGA overexpression enlarged leaves and reduced the number and length of roots. Overexpressing LhSLRL in tobacco caused a decreased plant height and the amount of root. Taken together, these results reveal that LhDELLA genes may play an important role in plant growth and development, especially in vegetative organs. Our results provide new insights into the function of DELLA genes in a woody plant, and contribute to a potential application of manipulating DELLA genetics.
Proposal for a System Model for Offline Seismic Event Detection in Colombia
Authors: Miranda Julián , Flórez Angélica , Ospina Gustavo , Gamboa Ciro , Flórez Carlos , Altuve Miguel
Published: December 2020

This paper presents an integrated model for seismic events detection in Colombia using machine learning techniques. Machine learning is used to identify P-wave windows in historic records and hence detect seismic events. The proposed model has five modules that group the basic detection system procedures: the seeking, gathering, and storage seismic data module, the reading of seismic records module, the analysis of seismological stations module, the sample selection module, and the classification process module. An explanation of each module is given in conjunction with practical recommendations for its implementation. The resulting model allows understanding the integration of the phases required for the design and development of an offline seismic event detection system.
Two Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function
Authors: Karamysheva Tatyana V. , Gayner Tatyana A. , Muzyka Vladimir V. , Orishchenko Konstantin E. , Rubtsov Nikolay B.
Published: December 2020

For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. In the case of a CCR, such as the one described here, the probability of gamete formation with a karyotype, showing a balance of chromosome regions, is extremely low. Recommendation for the family in genetic counseling should take into account the obtained result. In the case of an sSMC, it is critically important to identify the original chromosome from which the sSMC has been derived, even if the euchromatin material is absent. Finally, we present our view on the optimal strategy of identifying and describing sSMCs, namely the production of a microdissectional DNA probe from the sSMC combined with a consequent reverse painting.
Factors Affecting the Formation and Evolution of Permafrost and Stability Zone of Gas Hydrates: Case Study of the Laptev Sea
Authors: Matveeva Tatiana V. , Kaminsky Valery D. , Semenova Anastasiia A. , Shchur Nikolai A.
Published: December 2020

The key factors controlling the formation and dynamics of relicpermafrost and the conditions for the stability of associated gas hydrates have been investigated using numerical modeling in this work. A comparison was made between two scenarios that differed in the length of freezing periods and corresponding temperature shifts to assess the impact on the evolution of the permafrost–hydrate system and to predict its distribution and geometry. The simulation setup included the specific heat of gas hydrate formation and ice melting. Significantly, it was shown that the paleoscenario and heat flows affect the formation of permafrost and the conditions for gas hydrate stability. In the Laptev Sea, the minimum and maximum predicted preservation times for permafrost are 9 and 36.6 kyr, respectively, whereas the presence of conditions consistent with methane hydrate stability at the maximum permafrost thickness is possible for another 25.9 kyr. The main factors influencing the rate of permafrost degradation are the heat flow and porosity of frozen sediments. The rates of permafrost thawing are estimated to be between 1 and 3 cm/yr. It is revealed that the presence of gas hydrates slows the thawing of the permafrost and feeds back to prolong the conditions under which gas hydrates are stable.
Evaluation Instruments for Assessing Back Pain in Athletes: A Systematic Review Protocol
Authors: Azevedo Vinicius Diniz , Silva Regina Márcia Ferreira , Borges Silvia Cristina de Carvalho , Fernandes Michele da Silva Valadão , Miñana-Signes Vicente , Monfort-Pañego Manuel , Noll Priscilla Rayanne E Silva , Noll Matias
Published: December 2020

Back pain is a public health problem that affects adolescents and adults worldwide. However, studies on back pain present inconsistent findings in part due to the use of different instruments, especially for athletes. Therefore, the objective of this systematic review protocol was to map the existing evidence on such tools. The systematic review will be conducted according to PRISMA guidelines. Five electronic databases, Embase, MEDLINE, SPORTDiscus, CINAHL, and Scopus will be searched. This review includes studies that investigated prevalence, incidence, and other variables. Titles and abstracts will be selected. Two independent reviewers will read the articles carefully and discrepancies, if any, will be dealt with by a third reviewer. All steps will be completed with Rayyan for systematic reviews and the methodological quality will be analyzed with a COSMIN checklist. Discussion: This systematic review will gather evidence on tools that assess back pain in athletes. The findings may indicate the most appropriate tools for assessing back pain. They will contribute to better reliability, safe measurements, and help to standardize a comparison tool between different studies. They will also assist in the development of specific tools for athletes. Registration: This review was submitted and registered under CRD42020201299 in PROSPERO.
Effect of Natural Turf, Artificial Turf, and Sand Surfaces on Sprint Performance. A Systematic Review and Meta-Analysis
Authors: Sanchez-Sanchez Javier , Martinez-Rodriguez Alejandro , Felipe Jose Luis , Hernandez-Martin Antonio , Ubago-Guisado Esther , Bangsbo Jens , Gallardo Leonor , Garcia-Unanue Jorge
Published: December 2020

The aim of this study was to analyze the influence of natural turf, artificial turf, and sand on sprint performance in different sports and to determine how the sport surface affects sprint performance. A systematic search was conducted in Pubmed, Web of Sciences, and SPORTDiscus databases. Out of 5644 studies, 11 studies were included in the meta-analysis. The studies were very heterogeneous, as they examined different structural characteristics or quality parameters. The studies on natural turf and sand showed significant improvements on sprint speed during training. On the other hand, the analysis of fatigue did not reveal significant differences in the deterioration of sprint speed on both natural and artificial turf. Significance was set at p < 0.05. In conclusion, although lower performance in sprint was reported on sand, further studies are needed to explain the differences in sprint on natural and artificial turf.
Walking for Transport among Older Adults: A Cross-Sectional Study on the Role of the Built Environment in Less Densely Populated Areas in Northern Germany
Authors: Brüchert Tanja , Hasselder Pia , Quentin Paula , Bolte Gabriele
Published: December 2020

In the last decades, there has been rising interest in public health research in the importance of the built environment for a healthy and active life in old age, but little attention has been paid to less densely populated areas. This study aimed to explore the impact of the built environment on walking for transport in the context of an older population living in communities of <100,000 inhabitants. Within the project AFOOT–Securing urban mobility of an aging population, a cross-sectional postal survey was carried out from May to September 2019 in older adults (≥65 years) in the Metropolitan Region Northwest, Germany. Self-reported data from 2189 study participants were analyzed. Logistic and linear regression models were used to examine the associations between the built environment and walking for transport. Any walking and frequent walking were positively associated with nearly all built environment attributes, even after adjustment for demographic and health covariates. The amount of walking in minutes per week was associated only with residential density. Moderating effects of gender, age, and use of walking aids were identified. Improving the built environment appears to be a promising opportunity to motivate and enable older adults to walk for transport.
Associations between Maternal and Infant Illness and the Risk of Postpartum Depression in Rural China: A Cross-Sectional Observational Study
Authors: Min Wenbin , Nie Wei , Song Shuyi , Wang Nan , Nie Weiqi , Peng Lanxi , Liu Zhuo , Nie Jingchun , Yang Jie , Ma Yonghong , Shi Yaojiang
Published: December 2020

This study explored how maternal and infant illness correlated with the risk of postpartum depression in the Chinese Qinba Mountains region. In total, 131 villages comprising 435 families with infants (≤6 months old) were randomly sampled. We collected data on maternal and infant illnesses and maternal health knowledge level. The Depression, Anxiety, and Stress Scale-21 was used to measure the risk of postpartum depression. We used descriptive statistics and multivariate logistic regression for the analysis. Infant overall health status was a risk factor for postpartum depression (odds ratio (OR) = 1.90, 95% Confidence Interval (95% CI) = 1.10~3.28), whereas maternal overall health status was not correlated with postpartum depression (OR = 1.36, 95% CI = 0.55~3.39). For specific illnesses, infants experiencing over two common illnesses in the past two weeks (OR = 1.98, 95% CI = 1.13~3.45) and mothers experiencing over two common pains within two weeks after delivery (OR = 1.77, 95% CI = 1.02~3.08) were risk factors for postpartum depression, whereas infants with mild and severe stunted growth, maternal C-section, and postpartum body mass index (normal or overweight) were not correlated with it (all p > 0.050). Maternal health knowledge was an important moderator of maternal and infant illnesses on the risk of postpartum depression. In conclusion, maternal and infant illness were essential factors for the risk of postpartum depression in a poor rural region in western China, which may be mainly affected by the feeling of uncertainty of illness. Improved maternal and infant health and enhanced maternal health knowledge might alleviate the risk of postpartum depression.