bluuebunny/crossref_metadata_2025 huggingface dataset:
Johnston Atoll: Reef Fish Hybrid Zone between Hawaii and the Equatorial Pacific
Authors: Lobel Phillip S. , Lobel Lisa K. , Randall John E.
Published: February 2020

Johnston Atoll is isolated in the Central Pacific Ocean (16°45′ N 169°31′ W) about 1287 km (800 miles) southwest of Honolulu, Hawaii and 1440 km (900 miles) north of the equatorial Line Islands, Kiribati. The labrid species, Thalassoma lutescens, has a wide range of distribution in the equatorial Pacific. The related species, Thalassoma duperrey, is endemic to the Hawaiian Islands. The pelagic larvae of both species dispersed to Johnston Atoll, where we found a mix of adult phenotypes representing a range of hybridization events over generations. A hybrid acanthurid was also documented. In addition, the arrival and colonization of two pomacentrid (damselfish) species to the atoll was observed in 1999. These pomacentrid sister-species, Abudefduf abdominalis and A. vaigiensis, have become established populations with subsequent hybridization. The biogeography of the Johnston Atoll coral reef fish population shows some degree of local population retention. It is also evident that this biogeographic isolation is periodically compromised by large ocean current oscillations in the equatorial and central Pacific Ocean that bring larval fishes from either Hawaii or the Line Islands, and may distribute Johnston Atoll originating larvae elsewhere as well. The reef fauna and oceanography of this atoll provides the circumstances for improving scientific insight into marine fish speciation and island biogeography.
Prognostic Value of Circulating IGFBP2 and Related Autoantibodies in Children with Metastatic Rhabdomyosarcomas
Authors: Poli Elena , Zin Angelica , Cattelan Manuela , Tombolan Lucia , Zanetti Ilaria , Scagnellato Angela , Bonvini Paolo , Bisogno Gianni
Published: February 2020

Insulin-like growth factor-binding protein 2 (IGFBP2) is a tumor-associated protein measurable in patients’ biopsies and blood samples. Increased IGFBP2 expression correlates with tumor severity in rhabdomyosarcoma (RMS). Thus, we examined the plasmatic IGFBP2 levels in 114 RMS patients and 15 healthy controls by ELISA assay in order to evaluate its value as a plasma biomarker for RMS. Additionally, we looked for the presence of a humoral response against IGBFP2 protein measurable by the production of anti-IGFBP2 autoantibodies. We demonstrated that both circulating IGFBP2 protein and autoantibodies were significantly higher in RMS patients with respect to controls and their combination showed a better discriminative capacity. IGFBP2 protein identified metastatic patients with worse event-free survival, whereas both IGFBP2 and anti-IGFBP2 antibodies negatively correlated with overall survival. Our study suggests that IGFBP2 and anti-IGFBP2 antibodies are useful for diagnostic and prognostic purposes, mainly as independent negative prognostic markers in metastatic patients. This is the first study that reports a specific humoral response in RMS plasma samples and proves the value of blood-based biomarkers in improving risk assessment and outcome of metastatic RMS patients.
Entropy, Information, and Symmetry; Ordered Is Symmetrical, II: System of Spins in the Magnetic Field
Authors: Bormashenko Edward
Published: February 2020

The second part of this paper develops an approach suggested in Entropy 2020, 22(1), 11; which relates ordering in physical systems to symmetrizing. Entropy is frequently interpreted as a quantitative measure of “chaos” or “disorder”. However, the notions of “chaos” and “disorder” are vague and subjective, to a great extent. This leads to numerous misinterpretations of entropy. We propose that the disorder is viewed as an absence of symmetry and identify “ordering” with symmetrizing of a physical system; in other words, introducing the elements of symmetry into an initially disordered physical system. We explore the initially disordered system of elementary magnets exerted to the external magnetic field H → . Imposing symmetry restrictions diminishes the entropy of the system and decreases its temperature. The general case of the system of elementary magnets demonstrating j-fold symmetry is studied. The T j = T j interrelation takes place, where T and T j are the temperatures of non-symmetrized and j-fold-symmetrized systems of the magnets, correspondingly.
A Novel Five-Dimensional Three-Leaf Chaotic Attractor and Its Application in Image Encryption
Authors: Wang Tao , Song Liwen , Wang Minghui , Chen Shiqiang , Zhuang Zhiben
Published: February 2020

This paper presents a novel five-dimensional three-leaf chaotic attractor and its application in image encryption. First, a new five-dimensional three-leaf chaotic system is proposed. Some basic dynamics of the chaotic system were analyzed theoretically and numerically, such as the equilibrium point, dissipative, bifurcation diagram, plane phase diagram, and three-dimensional phase diagram. Simultaneously, an analog circuit was designed to implement the chaotic attractor. The circuit simulation experiment results were consistent with the numerical simulation experiment results. Second, a convolution kernel was used to process the five chaotic sequences, respectively, and the plaintext image matrix was divided according to the row and column proportions. Lastly, each of the divided plaintext images was scrambled with five chaotic sequences that were convolved to obtain the final encrypted image. The theoretical analysis and simulation results demonstrated that the key space of the algorithm was larger than 10150 that had strong key sensitivity. It effectively resisted the attacks of statistical analysis and gray value analysis, and had a good encryption effect on the encryption of digital images.
Input Pattern Classification Based on the Markov Property of the IMBT with Related Equations and Contingency Tables
Authors: Finta István , Szénási Sándor , Farkas Lóránt
Published: February 2020

In this contribution, we provide a detailed analysis of the search operation for the Interval Merging Binary Tree (IMBT), an efficient data structure proposed earlier to handle typical anomalies in the transmission of data packets. A framework is provided to decide under which conditions IMBT outperforms other data structures typically used in the field, as a function of the statistical characteristics of the commonly occurring anomalies in the arrival of data packets. We use in the modeling Bernstein theorem, Markov property, Fibonacci sequences, bipartite multi-graphs, and contingency tables.
The Self-Simulation Hypothesis Interpretation of Quantum Mechanics
Authors: Irwin Klee , Amaral Marcelo , Chester David
Published: February 2020

We modify the simulation hypothesis to a self-simulation hypothesis, where the physical universe, as a strange loop, is a mental self-simulation that might exist as one of a broad class of possible code theoretic quantum gravity models of reality obeying the principle of efficient language axiom. This leads to ontological interpretations about quantum mechanics. We also discuss some implications of the self-simulation hypothesis such as an informational arrow of time.
Towards a Model of Teacher Well-Being from a Positive Emotions Perspective
Authors: Manasia Loredana , Pârvan Andrei , Macovei Melania
Published: February 2020

Teacher well-being represents a key factor in assuring the quality of learning in terms of both process and outcomes. Despite a growing literature addressing the role of job demands and job resources in teacher well-being, fewer studies have focused on the effect of individual variables. The present paper aims at developing a teacher well-being model using self-efficacy and teaching emotions such as enjoyment of teaching, anger and anxiety to explain the influence of job demands and job resources on teachers’ subjective happiness. A cross-sectional quantitative design was applied to a sample of 1092 Romanian pre-university teachers. The participants completed a self-report questionnaire. Descriptive statistics, factor analysis and structural equations modelling were used to analyse the data. The findings indicate significant paths between the variables included in the model. Thus, job resources have a considerable positive influence on the enjoyment of teaching and the teachers’ subjective happiness, having a more powerful effect than personal resources, namely self-efficacy. In turn, perceived self-efficacy mediates the effect of job demands on teaching emotions and subjective well-being. It is argued that the enjoyment of teaching has a notable effect on teachers’ general well-being.
An Energy Storage System’s Operational Management and Control Method Considering a Battery System
Authors: Lee Jeong , Kim Jun-Mo , Ryu Kyung , Won Chung-Yuen
Published: February 2020

Losses in energy storage systems (ESSs) result from losses in battery systems and power conversion systems (PCSs). Thus, the power difference between the input and output occurs as a loss, which is considered an operational cost. Additionally, since battery systems consist of modules, there is always a temperature difference. Even if voltage balancing is conducted, deviations between the state of health (SoH) and state of charge (SoC) always exist. Therefore, a battery characteristic should be considered in relation to the efficient operation of an ESS. In this paper, charging control is implemented based on the SoC. When errors occur in the beginning, the coulomb counting method (CCM) continues to produce errors; it also calculates the SoC through an improved equation. Thus, it can calculate the SoC by using high-accuracy initial values. Moreover, battery deterioration occurs during charging and discharging, which increases a battery’s internal resistance. This reduces the switching time to the battery cut-off voltage or constant voltage (CV) mode, so it becomes possible to calculate the SoH. Therefore, in this paper, the algorithms and equations are proposed to perform SoH operations according to the charging time that is able to reach CV after charging. A conventional battery is usually charged by using constant current (CC) charging until the voltage of the battery module reaches the cut-off area. A switch to CV then occurs when the cut-off area is reached and maintained. However, SoC-based selective charging control is carried out to prevent heat problems. In addition, the battery is charged safely and efficiently by conducting SoH prediction considering the battery thermal characteristics, which vary depending on the charging time and other characteristics. In this paper, a 3 kW ESS was produced, and the proposed algorithm’s feasibility was verified.
Research on Simplified Model of AC/DC Hybrid Microgrid for Fault Analysis
Authors: Yao Tianliang , Li Zhiwei , Qu Jiping , Li Zhaoxiong , Zhao Qi , Zhao Guopeng
Published: February 2020

The AC/DC hybrid microgrid, which takes into account the access requirements of AC and DC sources and loads, optimizes the structure of traditional distribution networks. The application of power electronic transformers as the core of its energy management, with electrical isolation and accurate control of the voltage, current and power flow by the control system, enables the microgrid to achieve a more flexible and stable transmission mode. Because the power electronic transformer combines the power electronic device and the high-frequency transformer, its frequent switching causes the electromagnetic transient simulation to take too long. Therefore, by simplifying control loops and converters, this paper proposes a simplified model for the microgrid system power flow and the dynamic response under exposure to a fault. The mathematical model equivalent simplification method is used in this paper. This method is concise and efficient and does not rely on the performance of a computer or change the program algorithm of the software. The simplified model was built based on PSCAD (Power System Computer Aided Design) simulation software and was carried out under short circuit fault conditions to verify its validity. The comparison of the simulation’s time consumption and accuracy shows that model simplification can significantly improve the simulation speed, with an acceptable error rate, and its dynamic response maintains good consistency with that of the detailed electromagnetic transient model. Therefore, it can be applied to the transient electromagnetic simulation fault analysis of the AC/DC hybrid microgrid.
Power Quality Assessment of Grid-Connected PV System in Compliance with the Recent Integration Requirements
Authors: Al-Shetwi Ali Q. , Hannan M A , Jern Ker Pin , Alkahtani Ammar A. , PG Abas A. E.
Published: February 2020

The generation and integration of photovoltaic power plants (PVPPs) into the utility grid have increased dramatically over the past two decades. In this sense, and to ensure a high quality of the PVPPs generated power as well as a contribution on the power system security and stability, some of the new power quality requirements imposed by different grid codes and standards in order to regulate the installation of PVPPs and ensure the grid stability. This study aims to investigate the recent integration requirements including voltage sag, voltage flicker, harmonics, voltage unbalance, and frequency variation. Additionally, compliance controls and methods to fulfill these requirements are developed. In line with this, a large-scale three-phase grid-connected PVPP is designed. A modified inverter controller without the use of any extra device is designed to mitigate the sage incidence and achieve the low-voltage ride-through requirement. It can efficiently operate at normal conditions and once sag or faults are detected, it can change the mode of operation and inject a reactive current based on the sag depth. A dynamic voltage regulator and its controller are also designed to control the voltage flicker, fluctuation, and unbalance at the point of common coupling between the PVPP and the grid. The voltage and current harmonics are reduced below the specified limits using proper design and a RLC filter. The obtained results show that the proposed controller fulfilled the recent standard requirements in mitigating power quality (PQ) events. Thus, this study can increase the effort towards the development of smooth PVPP integration by optimizing the design, operation and control strategies towards high PQ and green electricity.
Wide Voltage Resonant Converter Using a Variable Winding Turns Ratio
Authors: Lin Bor-Ren , Dai Chu-Xian
Published: February 2020

This paper presents a inductor–inductor–capacitor (LLC) resonant converter with variable winding turns to achieve wide voltage operation (100–400 V) and realize soft switching operation over the entire load range. Resonant converters have been developed for consumer power units in computers, power servers, medical equipment, and adaptors due to the advantages of less switching loss and better circuit efficiency. The main disadvantages of the LLC resonant converter are narrow voltage range operation owing to wide switching frequency variation and limited voltage gain. For computer power supplies with hold-up time function, electric vehicle battery chargers, and for power conversion in solar panels, wide input voltage or wide output voltage operation capability is normally demanded for powered electronics. To meet these requirements, the variable winding turns are used in the presented circuit to achieve high- or low-voltage gain when Vin is at low- or high-voltage, respectively. Therefore, the wide voltage operation capability can be implemented in the presented resonant circuit. The variable winding turns are controlled by an alternating current (AC) power switch with two back-to-back metal-oxide-semiconductor field-effect transistors (MOSFETs). A 500-W prototype is implemented and test results are presented to confirm the converter performance.
New Dispatching Paradigm in Power Systems Including EV Charging Stations and Dispersed Generation: A Real Test Case
Authors: Cazzato Fabio , Di Clerico Marco , Falvo Maria Carmen , Ferrero Simone , Vivian Marco
Published: February 2020

Electric Vehicles (EVs) are becoming one of the main answers to the decarbonization of the transport sector and Renewable Energy Sources (RES) to the decarbonization of the electricity production sector. Nevertheless, their impact on the electric grids cannot be neglected. New paradigms for the management of the grids where they are connected, which are typically distribution grids in Medium Voltage (MV) and Low Voltage (LV), are necessary. A reform of dispatching rules, including the management of distribution grids and the resources there connected, is in progress in Europe. In this paper, a new paradigm linked to the design of reform is proposed and then tested, in reference to a real distribution grid, operated by the main Italian Distribution System Operator (DSO), e-distribuzione. First, in reference to suitable future scenarios of spread of RES-based power plants and EVs charging stations (EVCS), using Power Flow (PF) models, a check of the operation of the distribution grid, in reference to the usual rules of management, is made. Second, a new dispatching model, involving DSO and the resources connected to its grids, is tested, using an Optimal Power Flow (OPF) algorithm. Results show that the new paradigm of dispatching can effectively be useful for preventing some operation problems of the distribution grids.
One-Step or Two-Step Acid/Alkaline Pretreatments to Improve Enzymatic Hydrolysis and Sugar Recovery from Arundo Donax L.
Authors: Tang Shangyuan , Cao Yushen , Xu Chunming , Wu Yue , Li Lingci , Ye Peng , Luo Ying , Gao Yifan , Liao Yonghong , Yan Qiong , Cheng Xiyu
Published: February 2020

Energy crops are not easily converted by microorganisms because of their recalcitrance. This necessitates a pretreatment to improve their biodigestibility. The effects of different pretreatments, as well as their combination on the enzymatic digestibility of Arundo donax L. were systematically investigated to evaluate its potential for bioconversion. Dilute alkaline pretreatment (ALP) using 1.2% NaOH at 120 °C for 30 min resulted in the highest reducing sugar yield in the enzymatic hydrolysis process because of its strong delignification and morphological modification, while ferric chloride pretreatment (FP) was effective in removing hemicellulose and recovering soluble sugars in the pretreatment stage. Furthermore, an efficient two-step ferric chloride-alkaline pretreatment (FALP) was successfully developed. In the first FP step, easily degradable cellulosic components, especially hemicellulose, were dissolved and then effectively recovered as soluble sugars. Subsequently, the FP sample was further treated in the second ALP step to remove lignin to enhance the enzymatic hydrolysis of the hardly degradable cellulose. As a result, the integrated two-step process obtained the highest total sugar yield of 420.4 mg/g raw stalk in the whole pretreatment and enzymatic hydrolysis process; hence, the process is a valuable candidate for biofuel production.
Hydrodynamic Equilibrium Simulation and Shut-in Time Optimization for Hydraulically Fractured Shale Gas Wells
Authors: Wang Fei , Chen Qiaoyun , Ruan Yingqi
Published: February 2020

Post-fracturing well shut-in is traditionally due to the elastic closure of hydraulic fractures and proppant compaction. However, for shale gas wells, the extension of shut-in time may improve the post-fracturing gas production due to formation energy supplements by fracturing-fluid imbibition. This paper presents a methodology using numerical simulation to simulate the hydrodynamic equilibrium phenomenon of a hydraulically fractured shale gas reservoir, including matrix imbibition and fracture network crossflow, and further optimize the post-fracturing shut-in time. A mathematical model, which can describe the fracturing-fluid hydrodynamic transport during the shut-in process, and consider the distinguishing imbibition characteristics of a hydraulically fractured shale reservoir, i.e., hydraulic pressure, capillarity and chemical osmosis, is developed. The key concept, i.e., hydrodynamic equilibrium time, for optimizing the post-fracturing shut-in schedule, is proposed. The fracturing-fluid crossflow and imbibition profiles are simulated, which indicate the water discharging and sucking equilibrium process in the coupled fracture–matrix system. Based on the simulation, the hydrodynamic equilibrium time is calculated. The influences of hydraulic pressure difference, capillarity and chemical osmosis on imbibition volume, and hydrodynamic equilibrium time are also investigated. Finally, the optimal shut-in time is determined if the gas production rate is pursued and the fracturing-fluid loss is allowable. The proposed simulation method for determining the optimal shut-in time is meaningful to the post-fracturing shut-in schedule.
Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves
Authors: Halder Paresh , Takebe Hideki , Pawitan Krisna , Fujita Jun , Misumi Shuji , Shintake Tsumoru
Published: February 2020

A new type of wave energy converter which harnesses electricity from onshore breaking waves has been studied at Okinawa Institute of Science and Technology Graduate University (OIST) since 2014. This concept has been demonstrated at a coral beach on the Maldives since 2018. Wave energy conversion is possible when waves approaching the shore steepen due to decreased water depth resulting in wave breaks near the surface. A steepened wave reaches the critical velocity of 4~6 m/sec shoreward before it breaks. A rotating blade takes advantage of this breaking phenomenon to convert the wave energy into electricity. The work presented here includes an experimental and numerical investigation of a prototype model of the wave energy converter. The turbine having five blades of variable chord lengths, twist angles, and constant thickness profile from hub to tip was simulated under similar flow as well as testing conditions, to predict the turbine performance. A commercial computational fluid dynamic tool SolidWorks Flow Simulation 2018 was used for the simulations at various rotation speeds with a uniform inlet velocity. The modified k-ε with a two-scale wall function turbulence closure model was selected. The validation performed for different test cases showed that the present computational results match in good agreement with the experimental results. Additionally, details performance of the turbine running, and generator characteristics have been reported in this paper.
Estimation of Short Circuit Duration for the Assessment of Dynamic Effects in Distribution Substations with Flexible Conductors
Authors: Piechocki Piotr , Frackowiak Ryszard , Dombek Grzegorz , Chmielewska Irena
Published: February 2020

The paper focuses on finding short circuit duration for computing the dynamic effects in Extra High Voltage (EHV) distribution substations with flexible conductors with the use of probabilistic method. To find fault duration for selected substation points, a risk criterion was involved, namely the expected annual frequency of exceeding the calculated values of dynamic forces. A dedicated simulation model based on the Monte Carlo method was used to analyze the dynamic effects of short circuit current flow in the substation during faults within it and in its vicinity. The short circuit duration model is the key part of the simulation model. Due to the discussion of how the selected factors affect the estimated short circuit duration, indications helpful to find the values of the latter were formulated and some examples for the 220 kV distribution substation were given.
Numerical Study of Heated Tube Arrays in the Laminar Free Convection Heat Transfer
Authors: Brodnianská Zuzana , Kotšmíd Stanislav
Published: February 2020

Laminar free convection heat transfer from a heated cylinder and tube arrays is studied numerically to obtain the local and average Nusselt numbers. To verify the numerical simulations, the Nusselt numbers for a single cylinder were compared to other authors for the Rayleigh numbers of 103 and 104. Furthermore, the vertically arranged heated tube arrays 4 × 1 and 4 × 2 with the tube ratio spacing SV/D = 2 were considered, and obtained average Nusselt numbers were compared to the existing correlating equations. A good agreement of the average Nusselt numbers for the single cylinder and the bottom tube of the 4 × 1 tube array is proved. On the other hand, the bottom tubes of the 4 × 2 tube array affect each other, and the Nusselt numbers have a different course compared to the single cylinder. The temperature fields for the tube array 4 × 4 in basic, concave, and convex configurations are studied, and new correlating equations were determined. The simulations were done for the Rayleigh numbers in the range of 1.3 × 104 to 3.7 × 104 with a tube ratio spacing S/D of 2, 2.5, and 3. On the basis of the results, the average Nusselt numbers increase with the Rayleigh numbers and tube spacing increasing. The average Nusselt number and total heat flux density for the convex configuration increase compared to the base one; on the other hand, the average Nusselt number decreases for the concave one. The results are applicable to the tube heaters constructional design in order to heat the ambient air effectively.
Flowering Phenology and Characteristics of Pollen Aeroparticles of Quercus Species in Korea
Authors: Kim Iereh , Kwak Myeong Ja , Lee Jong Kyu , Lim Yeaji , Park Sanghee , Kim Handong , Lee Keum-Ah , Woo Su Young
Published: February 2020

In recent decades, airborne allergens for allergic respiratory diseases have been found to increase significantly by a process of converting coniferous forests into broad-leaved forests in Korea. This study was conducted to evaluate factors, including airborne pollen counts, micromorphology, and flowering phenology, that can affect oak pollen-related allergic symptoms. The catkin of Mongolian oak (Quercus mongolica Fisch. ex Ledeb.) showed the most rapidly blooming catkin on Julian day 104 in flower development. Among six species, the last flowering was observed on Julian day 119 in Korean oak (Quercus dentata Thunb.). The pollen dispersal was persisted for about 32 days from Julian day 104 to Julian day 136. Airborne pollen was observed about 2 weeks after flowering phase H, the senescence phase. Pollen size varied by species, with the largest from Q. mongolica (polar axis length, PL = 31.72 µm, equatorial axis length, EL = 39.05 µm) and the smallest from Jolcham oak (Quercus serrata Murray) (PL = 26.47 µm, EL = 32.32 µm). Regarding pollen wall structure, endexine of Q. dentata was coarsely laminated or fragmented. The endexine thicknesses of Sawtooth oak (Quercus acutissima Carruth.) and Q. serrata were thick and stable, whereas Galcham oak (Quercus aliena Blume), Q. mongolica, and Oriental cork oak (Quercus variabilis Blume) had thinner endexines. The area occupied by pollenkitt of Q. variabilis was significantly larger than that of Q. acutissima. Importantly, Q. variabilis had a distinctly thick 17 kDa protein band, a presumed major allergen. Oak species differ in pollen protein composition, and thus there is a possibility that the allergenic activity of pollen proteins vary depending on oak species. This study highlights the fact that native oak species in Korea differ in flowering pattern of male flowers, pollen morphology, and pollen chemical constituents. These discrepancies in flowering and pollen properties imply variable allergic responses to oak pollen from different species.
What We Know and What We Do Not Know about Dragon Trees?
Authors: Maděra Petr , Forrest Alan , Hanáček Pavel , Vahalík Petr , Gebauer Roman , Plichta Roman , Jupa Radek , Van Rensburg Julian Jansen , Morris Miranda , Nadezhdina Nadezhda , Vaníčková Lucie , Jura-Morawiec Joanna , Wiland-Szymańska Justyna , Kalivodová Hana , Lengálová Klára , Rejžek Martin , Habrová Hana
Published: February 2020

This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species.
Low-Cost GNSS Software Receiver Performance Assessment
Authors: Cutugno Matteo , Robustelli Umberto , Pugliano Giovanni
Published: February 2020

The Software-Defined Receiver (SDR) is a rapidly evolving technology which is a useful tool for researchers and allows users an extreme level customization. The main aim of this work is the assessment of the performance of the combination consisting of the Global Navigation Satellite Systems Software-Defined Receiver (GNSS-SDR), developed by CTTC (Centre Tecnològic de Telecomunicacions de la Catalunya), and a low-cost front-end. GNSS signals were acquired by a Nuand bladeRF x-40 front-end fed by the TOPCON PG-A1 antenna. Particular attention was paid to the study of the clock-steering mechanism due to the low-cost characteristics of the bladeRF x-40 clock. Two different tests were carried out: In the first test, the clock-steering algorithm was activated, while in the second, it was deactivated. The tests were conducted in a highly degraded scenario where the receiver was surrounded by tall buildings. Single-Point and Code Differential positioning were computed. The achieved results show that the steering function guarantees the availability of more solutions, but the DRMS is quite the same in the two tests.
Trends in Tobacco Use among Children and Adolescents in Israel, 1998–2015
Authors: Tesler Riki , Kolobov Tanya , Korn Liat , Shuval Kerem , Levin-Zamir Diane , Marques Adilson , Harel Fisch Yossi
Published: February 2020

Objectives: This study aims to measure trends in cigarette smoking among children and adolescents in Israel, focusing on school grade, sex, and ethnicity. We hypothesized that smoking would be higher among boys and Arab-Israelis, rates would grow with age, and there would be a decline over time. Methods: Data were derived from the Health Behavior in School-aged Children study between 1998 and 2015 in Israel. The total sample included 56,513 students in grades 6, 8, and 10, with 29,411 girls and 27,102 boys. Descriptive analysis described trends of smoking behavior according to grade, sex, ethnicity, family affluence, and year of study. multivariate logistic regression analysis examined predicting variables. Results: Smoking was higher among boys in all grades, ethnic groups, and years of study, with the highest frequencies among Arab-Israelis. Trends over the years show a decline from 1998 to 2004, followed by an increase for both sexes. The increase was more prominent among girls. Logistic regression analysis revealed strong associations between smoking and grade, sex, ethnicity, and year of study. Conclusions: The results of this study can significantly enhance the development and implementation of smoking prevention and control programs among students in Israel.
Entrepreneurs and Environmental Sustainability in the Digital Era: Regional and Institutional Perspectives
Authors: Ye Qing , Zhou Rongting , Anwar Muhammad Azfar , Siddiquei Ahmad Nabeel , Asmi Fahad
Published: February 2020

Climate change and environmental degradation have negatively affected the sustainable development of mankind. The “green” concept has been gradually accepted by the public, thereby strongly promoting “green” business forms and social innovation. This study adopts related information and technology knowledge and experience and warm glow (altruistic value) for business initiatives as push factors, market opportunity (MO) and personal innovativeness (PI) in technology as pull factors, and institutional theory (regulatory support and normative support) as mooring factors. These factors are employed to analyze the switching intentions of individuals toward green entrepreneurship, which is a new persuasive psychological model based on Push–Pull–Mooring model (PPM). The survey questionnaires are collected from a total of 1562 respondents through WeChat in mainland China. The study findings present all variables that significantly affect individuals’ switching intentions toward green entrepreneurs. PI exhibits the most significant impact on intention of individuals toward green entrepreneurship, while the interaction between the mooring factor and MO on switching intentions to green entrepreneurship is relatively weak. Finally, the study contributes theoretical and practical implications for increasing intentions toward green entrepreneurship.
Burnout and Self-Perceived Instructional Competence: An Exploratory Study of a Group of Italian Female Elementary School Teachers
Authors: Pellerone Monica , Rapisarda Venerando , Trischitta Maria Chiara Antonietta , Vitale Ermanno , Ramaci Tiziana
Published: February 2020

Since the first half of the 1980s, burnout in teachers has been the object of particular attention by many international authors. Teachers are subject, more than other professions, to numerous and heavy pressures, covering the peculiarity of the profession. The objectives of the present research are to measure the predictive role of emotional exhaustion, depersonalization, and personal accomplishment on the quality of teaching in a group of elementary school teachers. We carried out a cross-sectional study involving 324 Sicilian female teachers, who worked in three school orders: Kindergarten, primary school, and the first year of middle school. Participants completed a socio-demographic questionnaire, the assessment teaching scale for primary school teachers (ECAD-EP), and the Maslach Burnout Inventory (MBI). In reference to the level of burnout, the correlation analysis underlined the presence of a positive correlation between: Emotional exhaustion and depersonalization; and a negative correlation between exhaustion and depersonalization. Furthermore, a predictive role of emotional exhaustion, depersonalization, and personal accomplishment on the quality of teaching in a group of primary school teachers was found.
Forecasting Flu Activity in the United States: Benchmarking an Endemic-Epidemic Beta Model
Authors: Lu Junyi , Meyer Sebastian
Published: February 2020

Accurate prediction of flu activity enables health officials to plan disease prevention and allocate treatment resources. A promising forecasting approach is to adapt the well-established endemic-epidemic modeling framework to time series of infectious disease proportions. Using U.S. influenza-like illness surveillance data over 18 seasons, we assessed probabilistic forecasts of this new beta autoregressive model with proper scoring rules. Other readily available forecasting tools were used for comparison, including Prophet, (S)ARIMA and kernel conditional density estimation (KCDE). Short-term flu activity was equally well predicted up to four weeks ahead by the beta model with four autoregressive lags and by KCDE; however, the beta model runs much faster. Non-dynamic Prophet scored worst. Relative performance differed for seasonal peak prediction. Prophet produced the best peak intensity forecasts in seasons with standard epidemic curves; otherwise, KCDE outperformed all other methods. Peak timing was best predicted by SARIMA, KCDE or the beta model, depending on the season. The best overall performance when predicting peak timing and intensity was achieved by KCDE. Only KCDE and naive historical forecasts consistently outperformed the equal-bin reference approach for all test seasons. We conclude that the endemic-epidemic beta model is a performant and easy-to-implement tool to forecast flu activity a few weeks ahead. Real-time forecasting of the seasonal peak, however, should consider outputs of multiple models simultaneously, weighing their usefulness as the season progresses.
Distribution, Origins and Hazardous Effects of Polycyclic Aromatic Hydrocarbons in Topsoil Surrounding Oil Fields: A Case Study on the Loess Plateau, China
Authors: Wang Di , Zhu Shilei , Wang Lijing , Zhen Qing , Han Fengpeng , Zhang Xingchang
Published: February 2020

The Loess Plateau has one of the most vulnerable ecological environments in the world, but it also contains abundant oil and gas resources that are regularly exploited, which has resulted in serious environmental problems. Therefore, it is important to analyze the polycyclic aromatic hydrocarbons (PAHs) present in the topsoil of this region. The ∑16PAHs concentrations between 1980–1999 and 2000–2019 ranged from 1134.20–15871.04 and 1010.67–18,068.80 µg kg−1, with average values of 5021.30 and 5662.82 µg kg−1. All samples displayed heavy pollution levels according to European soil quality standards. In addition, among the measured physicochemical properties, the soil organic carbon (SOC) had the greatest influence on PAHs, while soil particle size distribution had the smallest effect. Source apportionment indicated that the two main sources were petroleum source (37.57%) and vehicular traffic source (25.88%). Lastly, an assessment of the carcinogenic risks illustrated that more focus should be placed on the dermal pathway in which the human body is exposed to soil PAHs. Overall, the carcinogenic risks in different populations did not exceed 10−4, but there was still a potential carcinogenic risk in some age groups, especially in adult women.
A Longitudinal Study of Authoritative Parenting, Juvenile Delinquency and Crime Victimization among Chinese Adolescents
Authors: Xiong Ruoshan , Li Spencer De , Xia Yiwei
Published: February 2020

Empirical research on the relationship between authoritative parenting and crime victimization has been sparse, although this style of parenting has been identified as an effective parenting practice for inhibiting offending behavior among children and adolescents. The current research aims at filling this gap by examining the influences of authoritative parenting on juvenile delinquency and crime victimization, as well as the mechanisms connecting the processes. Using two-wave survey data collected from a probability sample of 1066 Chinese adolescents, the current study employed a structural equation modeling analysis to test the relationships. The results indicated that authoritative parenting negatively predicted juvenile delinquency and crime victimization. Further, adolescent mental health problems and delinquent peer association partially mediated the influence of authoritative parenting on delinquency, while adolescent mental health problems, delinquent peer association, and juvenile delinquency fully mediated the relationship between authoritative parenting and crime victimization. The results also showed that juvenile delinquency positively predicted future crime victimization. Overall, this study demonstrated that authoritative parenting operated as a protective factor against juvenile delinquency and crime victimization.
Cerebral Oxygenation Reserve: The Relationship Between Physical Activity Level and the Cognitive Load During a Stroop Task in Healthy Young Males
Authors: Goenarjo Roman , Bosquet Laurent , Berryman Nicolas , Metier Valentine , Perrochon Anaick , Fraser Sarah Anne , Dupuy Olivier
Published: February 2020

Introduction: Many studies have reported that regular physical activity is positively associated with cognitive performance and more selectively with executive functions. However, some studies reported that the association of physical activity on executive performance in younger adults was not as clearly established when compared to studies with older adults. Among the many physiological mechanisms that may influence cognitive functioning, prefrontal (PFC) oxygenation seems to play a major role. The aim of the current study was to assess whether executive function and prefrontal oxygenation are dependent on physical activity levels (active versus inactive) in healthy young males. Methods: Fifty-six healthy young males (22.1 ± 2.4 years) were classified as active (n = 26) or inactive (n = 30) according to the recommendations made by the World Health Organization (WHO) and using the Global Physical Activity Questionnaire (GPAQ). Bilateral PFC oxygenation was assessed using functional near-infrared spectroscopy (fNIRS) during a computerized Stroop task (which included naming, inhibition, and switching conditions). Accuracy (% of correct responses) and reaction times (ms) were used as behavioural indicators of cognitive performances. Changes in oxygenated (∆HbO2) and deoxygenated (∆HHb) hemoglobin were measured to capture neural changes. Several two-way repeated measures ANOVAs (Physical activity level x Stroop conditions) were performed to test the null hypothesis of an absence of interaction between physical activity level and executive performance in prefrontal oxygenation. Results: The analysis revealed an interaction between physical activity level and Stroop conditions on reaction time (p = 0.04; ES = 0.7) in which physical activity level had a moderate effect on reaction time in the switching condition (p = 0.02; ES = 0.8) but not in naming and inhibition conditions. At the neural level, a significant interaction between physical activity level and prefrontal oxygenation was found. Physical activity level had a large effect on ΔHbO2 in the switching condition in the right PFC (p = 0.04; ES = 0.8) and left PFC (p = 0.02; ES = 0.96), but not in other conditions. A large physical activity level effect was also found on ΔHHb in the inhibition condition in the right PFC (p < 0.01; ES = 0.9), but not in the left PFC or other conditions. Conclusion: The results of this cross-sectional study indicate that active young males performed better in executive tasks than their inactive counterparts and had a larger change in oxygenation in the PFC during these most complex conditions.
Assessing the Performance of Land Consolidation Projects in Different Modes: A Case Study in Jianghan Plain of Hubei Province, China
Authors: Yang Bin , Wang Zhanqi , Yao Xiaowei , Chai Ji
Published: February 2020

Land consolidation is essential in China for improving land use efficiency and supporting rural public space governance. Previously, the implementation of land consolidation projects (LCPs) had been mainly led by governments in China. In recent years, the Chinese government vigorously promoted land consolidation, and land consolidation in the corporation-leading mode (CLM) has emerged. This study focused on investigating the performance of CLM projects and the difference in performance levels between the CLM projects and the government-leading mode (GLM) projects. Based on the improved extensible matter–element model, the performance levels of 14 LCPs in GLM and CLM of Jianghan Plain, Hubei Province and related impact factors were analyzed. A set of evaluation indices was selected based on the “process-based thinking and logic”. Results showed that: (1) performance levels of the 14 LCPs are different, most of the projects in the GLM have ordinary or poor performance, while most of the projects in the CLM have excellent or good performance; (2) factors affecting the performance levels of LCPs are also different in the two modes. The main influencing factors in the CLM were the poor access to field roads, insufficient shelterbelt planting, and low land reclamation efficiency, while the insufficient shelterbelt planting, low annual output value of farmland and grain production capacity, low increase rate of agricultural labor production, and low land reclamation efficiency were the main influencing factors in the GLM; (3) comparative analysis of the two modes revealed that LCPs in the CLM have clear investment directions, high output benefits, and obvious advantages in the development of modern agriculture when compared with the GLM. To achieve improving the performance levels of LCPs, policy makers should actively innovate the implementation mode of LCPs and encourage all kinds of agricultural corporations to participate in land consolidation.
Attitudes of Teenage Mothers towards Pregnancy and Childbirth
Authors: Bałanda-Bałdyga Agnieszka , Pilewska-Kozak Anna Bogusława , Łepecka-Klusek Celina , Stadnicka Grażyna , Dobrowolska Beata
Published: February 2020

The problem of early motherhood is still a serious medical and social problem in many countries around the world. The aim of this study was to analyze the attitudes of teenage mothers towards pregnancy and childbirth. A retrospective cross-sectional study was conducted with the use of an original questionnaire containing a test to measure attitudes on a five-point Likert scale and a Life Orientation Test-Revised (LOT-R) to assess dispositional optimism. The study involved 308 teenage mothers between 13 and 19 years of age. Attitudes of teenage mothers towards pregnancy and childbirth were more often positive (90.6%) than negative (9.4%). Sociodemographic features determining the attitudes of teenage mothers towards both their pregnancy and childbirth included their age, marital status, current occupation, and main source of income. The type of attitude adopted by teenage mothers towards pregnancy and childbirth was significantly related to the level of their dispositional optimism.
β3-Adrenoreceptor Blockade Induces Stem Cells Differentiation in Melanoma Microenvironment
Authors: Calvani Maura , Bruno Gennaro , Dabraio Annalisa , Subbiani Angela , Bianchini Francesca , Fontani Filippo , Casazza Gabriella , Vignoli Marina , De Logu Francesco , Frenos Stefano , Filippi Luca , Favre Claudio
Published: February 2020

Although there is an increasing evidence that cancer stem cell (CSC) niches in the tumor microenvironment (TME) plays a crucial role in sustaining solid tumors progression, several molecular players involved in this regulation still remain unknown. The role of β-adrenergic signaling in enhancing tumor growth through β2-adrenoreceptors (β2-ARs) has been confirmed in different cancer models, but the role played by the β3-adrenergic receptor (β3-AR) has recently emerged. Previous studies showed that β3-AR promotes cancer growth through the activation of different stromal cells in the TME, and leads to melanoma malignancy progression through inflammation, angiogenesis, and immunotolerance. Here we show that in B16 melanoma-bearing mice, the pharmacological β3-AR blockade is able to reduce the expression of CSC markers, and to induce a differentiated phenotype of hematopoietic subpopulations in TME. In particular, cytofluorimetric analysis (FACS) of the tumor mass shows that β3-AR antagonist SR59230A promotes hematopoietic differentiation as indicated by increased ratios of lymphoid/hematopoietic stem cells (HSCs) and of myeloid progenitor cells/HSCs, and increases the number of Ter119 and natural killer (NK) precursor cells, and of granulocyte precursors, indicating active hematopoiesis within the tumor tissue. Moreover, pharmacological antagonism of β3-AR induces mesenchymal stem cell (MSC) differentiation into adipocytes subtracting a potential renewal of the stem compartment by these cells. Here we demonstrate that β3-AR blockade in the TME by inducing the differentiation of different stromal cells at the expense of stemness traits could possibly have a favorable effect on the control of melanoma progression.