bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracing Successful Online Teaching During Covid-19 Pandemic
Authors: Subarno Anton , Sulistyaningrum Cicilia Dyah , Umam Muhammad Choerul , Winarno
Published: March 2021

The world of education dismisses students (studying at home) to reduce the spread of the coronavirus. In such conditions, teachers are challenged to apply all their abilities and expertise so that they can continue to teach students by transferring knowledge, pedagogic abilities, and their belief in successful online learning. This study aims to explore how lecturers can conduct teaching in the midst of the Covid-19 pandemic and what they use as a medium to conduct successful online teaching. In addition, researchers also want to know how lecturers can adjust the online teaching transition. The design of this research is qualitative research using deep interview tests to explore online learning that suits current needs. The research was conducted at the department of Office Administration Education Sebelas Maret University with the head of the study program as the key informant. The data validity test used source triangulation and method triangulation. The sampling technique was purposive snowball sampling, data collection techniques used observation, interviews and documentation, and data analysis techniques used interactive data reduction, data presentation, and conclusion drawing. The results show a good connection communication network of all students and lecturers is a major aspect that must be considered in lectures even though using simultaneously online social media, e.g. You Tube, Google Classroom, Google Meet, and WhatsApp. The Covid-19 pandemic is considered a challenge and an opportunity to conduct research in the field of information and communication technology (ICT) especially on digital classroom management. The outcomes of research that can be directly utilized by the user are the output targets research whose activities are manifested in the form of community service. Community Service Program (KKN) is a tangible form of student involvement in community service.
Pseudo Thinking Process in Understanding the Concept of Exponential Equations
Authors: Muslim R I , Usodo B , Pratiwi H
Published: March 2021

The thought process is a very interesting thing to examine in mathematics learning. Sometimes in solving questions, students’ answers are wrong not because of the wrong thinking process, as well as correct answers, it is not certain that students understand why the process was carried out. Such conditions occur because the students’ thought processes are pseudo, meaning that the thought process that occurs is not a reflection of the real thought process. The focus in this study is students who experience pseudo thinking in understanding the concept of exponential equations. The pseudo thinking categories are grouped according to the Vinner and Subanji frameworks. Based on the research results, the students’ pseudo thinking process in understanding the concept of exponential equations was shown that most students in understanding the concept of exponential equations still memorized the formula without understanding the formula. Students only think of looking for answers quickly using formulas that have been learned. If learning only emphasizes procedures and memorization, what happens learning mathematics has no meaning. In addition to memorizing procedures, it is very risky for students to forget, students are not able to use mathematics according to the actual concept.
Reflective Abilities in Students with a High Level of Self-confidence
Authors: Hidayat N , Usodo B , Saputro D R S
Published: March 2021

Reflective thinking is the student’s ability to actively and carefully answer a given problem. The purpose of this study was to determine the reflective thinking ability of students with high levels of self-confidence. This research is descriptive qualitative, with the researcher as the main instrument and other supporting instruments in the form of a reflective thinking ability test, self-confidence questionnaire, and interview guidelines. The results of the questionnaire showed that there were nine grade VIII B students of SMPN 1 Pundong who had high self-confidence, two subjects in this study were selected by purposive sampling. The results showed that six out of nine students with high self-confidence were able to meet all indicators of reflective thinking. The other three students are only able to meet a fraction of the five indicators. The inability to think reflective because students are not used to linking old knowledge to be used in solving new problems, and students are also less careful in solving problems because students are unable to check the answers that have been obtained.
High School Students’ Mathematical Problem Solving Skills Based on Krulik and Rudnick Steps Reviewed from Thinking Style
Authors: Rahmah A , Mardiyana  , Saputro D R S
Published: March 2021

This research explains the problem solving skills of students of Grade XII MIPA SMA MTA Surakarta based on Krulik and Rudnick’s steps that are reviewed from the thinking style. This research is a qualitative study that produces descriptive data. The study began by determining the subject of the study by using a thought style questionnaire, given problem solving tasks and interviews. The results showed math problem solving skills; 1) concrete sequential student are systematically worked on and use an inductive mindset and the steps of reviewing and discussing are not implemented; 2) abstract sequential student are easy to present what is known in the question to mathematical symbol forms, collect data in detail, and manage the information obtained regularly and perform all of Krulik and Rudnick’s steps; 3) concrete random student are tend to be consistent in using guessing or experimenting strategies and work without detail and the steps of reviewing and discussing are not implemented: 4) abstract random student are fundamental differences in processing the information received and planning problem solving in a way of their own accord and doing all the steps krulik and rudnick.
The Effectiveness of Software GeoGebra to Improve Visual Representation Ability
Authors: Azizah A N , Kusmayadi T A , Fitriana L
Published: March 2021

GeoGebra is a mathematical software that supports learning mathematics to make it easier to visualize geometric shapes. Geography software can create geometric images that are 2 dimensional or 3 dimensional so that GeoGebra can help students to represent real geometric shapes. This research aims to view the effectiveness of GeoGebra software in improving students’ visual representation ability. This study used a one-group pre-test/post-test design pre-experiment. The sample in this ability were students of eight grades SMP Negeri Sukoharjo who studied the material of flat-sided building. The instruments used in this study were the pre-test with and post-test of mathematical representation abilities. The results showed that there was an effectiveness of using GeoGebra in improving students’ visual representation skills with the difference in the mean score of students after being given geoGebra treatment was 61.3 for the pre-test and 70.5 for the post-test.
E-book Based on Mobile Learning Used Problem Based Learning (PBL) Model to Improve Problem-Solving Ability in Statistical Material
Authors: Herdianto E N , Mardiyana  , Indriati D
Published: March 2021

The research aims to developed a mobile learning-based e-book that used problem-based learning (PBL) to improve problem-solving abilities in statistical materials that meets validity, practically, and effectiveness. The type is a Development Research used the Four-D model (define, design, development, and disseminate). The validation results of the material feasibility average was very good at 82% and the validation of the media was 85.92%. The results of the response questionnaire by students was 88.22% and by the teacher was 83.31%, included in the very practical category. Therefore the mobile learning-based e-book developed is valid to use in mathematics classes. The result of e-book effectiveness meets the effective criteria with the completeness study of students at 84%. From the products tested, it was concluded that the students problem-solving abilities in statistics material used mobile learning-based e-book that had been developed were better than used existing products. Thus, this mobile learning-based e-book used a problem-based learning model to improve problem-solving abilities in eighth grade of statistical material which is suitable for uses and recommended at mathematics learning.
Some applications of cloud technologies in mathematical calculations
Authors: Zhaldak M I , Franchuk V M , Franchuk N P
Published: March 2021

This article discusses some use of cloud technology in mathematical calculations using Remote Desktop Ulteo OVD. To use such technologies, it is enough to have access to the Internet through a suitable browser to access an open virtual desktop on a powerful remote computer and then use the resources of the remote computer (server) to solve their problems in processing various information resources – solving mathematical problems, working out texts, translating from one language to another, help on the interpretation of different terms, their origin and more. You can organize access to Ulteo OVD from two servers (Application Server (Windows 2008R2) and Session Manager Server (Linux Ubuntu)), using the Proxmox web-based virtual environment. Gran1, Gran2D, Gran3D software can be installed on the application server. The article also examines in detail some examples of the use of the pedagogical software for educational purposes Gran1. In particular, the calculation of the approximate value of the double integral; graphical two-dimensional problem solving, the so-called linear programming problems; two-dimensional problems, including convex programming – finding the smallest value of a convex downward function (or the highest convexity of a function) on a convex set of inequalities (including linear ones). However, the use in the educational process of any technology, including modern information and communication, as well as the content of training, should be pedagogically balanced, which will allow to avoid any negative effects on the formation of personality of a future member of society, his mental and physical development.
The arrangement of on-line training of master students, majoring in Mathematics for internship in technical universities
Authors: Vlasenko K V , Lovianova I V , Chumak O O , Sitak I V , Achkan V V
Published: March 2021

This article looks into the issue of online-training of master students, majoring in Mathematics for internship in technical universities. This study is focused on arranging students' learning activities with the help of an on-line course “Methods for teaching Mathematics to students in technical universities”. The study considers the issues that students face during the internship in technical universities and debates a possibility to factor in the students’ needs while designing the course content. The present study gives a description of the activities that students do while working with the course materials, requirements, and recommendations on facilitating the learning process through this course. Active participation of students and their contribution to discussing the course, its content and the facilitation of the learning process presume that introduction of the on-line course and its integration into the program of training master students enhances their readiness for internship.
The ICT usage in teaching mathematics to students with special educational needs
Authors: Kramarenko T , Bondar K , Shestopalova O
Published: March 2021

In the article, authors have considered the implication of ICT into mathematics educational strategies in the inclusive class of secondary school. The research includes also a presentation of a teacher’s tool, prepared by an author group, on the use of ICT in teaching planimetry and stochastics of children with special educational needs (SEN) in secondary schools. The research has introduced the model of implication ICT and the influence of effective strategies and methods of inclusive education on the math studying process by children with hearing disorder. The possibilities of using the method of educational projects as one of socialization directions are described. The efficiency of the distance learning was discovered that facilitates the self-representation of students with SEN.
Computational method for studying the thermal conductivity of molecular crystals in the course of condensed matter physics
Authors: Pursky O I , Dubovyk T V , Babenko V O , Gamaliy V F , Rasulov R A , Romanenko R P
Published: March 2021

This paper presents a computational method for studying the thermal conductivity of molecular crystals that can be used in the educational course of condensed matter physics. This method is based on the Debye model of thermal conductivity in the approximation of the corresponding relaxation times and allows studying the heat transfer processes features in simple molecular crystals at temperatures close to or above Debye temperature. The thermal conductivity is analysed in the framework of modified Debye model in which heat is transferred by low-frequency phonons and above the phonon mobility edge by “diffusive” modes migrating randomly from site to site. The mobility edge ω0
is found from the condition that the phonon mean-free path cannot become smaller than half the phonon wavelength. The contributions of phonon-phonon, one-, and two-phonon scattering to the total thermal resistance of molecular crystals are calculated under the assumption that the different scattering mechanisms contribute additively. The presented computational method will be useful in pedagogical activities for teaching students of physical faculties.
Use of augmented reality-enabled prototyping of cyber-physical systems for improving cyber-security education
Authors: Skorenkyy Yu , Kozak R , Zagorodna N , Kramar O , Baran I
Published: March 2021

The use of augmented reality-enabled scenarios in cybersecurity teaching is proposed in the article to respond to new requirements for the rapid adoption of new technologies and profound knowledge of cybersecurity issues by professionals. Implementation of project-type activities based on real cybersecurity issues in application fields of cyber-physical systems is suggested to improve the competence forming. A use-case of agricultural cyber-physical system of systems is discussed as a viable example of augmented reality-enabled prototyping of cybersecurity risk-aware architecture. The necessary steps are analysis of general and business-specific tasks on cybersecurity, creation of a list of competencies, formalized in educational standards and curricula, development of gaming scenarios for the formation of hard and soft skills, development of the scenario management system for AR interfaces. The system using AR tools can be easily adapted to different cybersecurity training activities. Industrial cyber-physical systems may be vulnerable due to insecure wireless connectivity, lack of encryption, inadequate access policy. The project-based learning complex is focused on the implementation of a data acquisition, storage and processing platform for new sensor networks and instruments. Representing all the diverse information on different layers will be greatly improved by use of the developed holographic projection AR tools.
The use of online coding platforms as additional distance tools in programming education
Authors: Zinovieva I S , Artemchuk V O , Iatsyshyn Anna V , Popov O O , Kovach V O , Iatsyshyn Andrii V , Romanenko Y O , Radchenko O V
Published: March 2021

This study analyzes various publications of scientists on the training of future IT specialists and the features of training programming using online simulators. The authors of the article made a comparative description of different online platforms for teaching programming according to certain criteria, selected interesting tasks from the online platform hackerrank.com, which have already been used to teach students. Online programming simulators have significant potential in organizing an effective distance learning system in Ukrainian universities. It is important to use online simulators in the learning process as an additional tool for the formation of professional competencies, which provides more intensive involvement of students in the process of writing code and practical (situational) application of existing knowledge. Gamification of the process of training future IT specialists helps to increase cognitive activity, and hence – the quality of the educational process and distance learning in particular. The authors recommend the use of online programming simulators as an additional tool for teaching computer science disciplines, taking into account their functionality, as well as the level of preparation of students and the expected learning outcomes.
Project-based learning in a computer modelling course
Authors: Balyk N , Grod I , Vasylenko Y , Oleksiuk V , Rogovchenko Yu
Published: March 2021

The paper reports authors’ experience of implementing educational projects in a computer modelling course offered to the students majoring in “Secondary Education (Computer Science)” at Ternopil Volodymyr Hnatiuk National Pedagogical University. We analyze approaches to teaching mathematical and computer modelling such as: integration of modelling tasks, naturalistic case study, using of role-playing games, possibilities of STEM-education, motivation and positive attitude to modelling training, etc. Then we illustrate the implementation of the project to study the population dynamics of the grape snail Helix pomatia. The implementation of the project splits into several stages: formulation of the problem, presentation of project tasks, brainstorming, development, testing, presentation of results. The study was conducted at Ternopil Volodymyr Hnatiuk National Pedagogical University within the Norwegian-Ukrainian Project “Development of students' mathematical competencies through Digital Mathematical Modelling” (DeDiMaMo) in partnership with the University of Agder (Norway) and Borys Grinchenko Kyiv University.
The impact of artificial intelligence on employment before and during pandemic: A comparative analysis
Authors: Abuselidze G , Mamaladze L
Published: March 2021

Current trends in scientific research and the development of information technologies cover more and more areas of business. In these conditions, the findings of scientific-technical revolution and the innovations most important factors for the country’s economic development and crucial to become a competitive state. The gradual establishment and the scope of use of artificial intelligence on the world innovative technology market increases daily. The purpose of this work is to investigate its impact on business based on the experience of the world and particularly, in Georgia. Accordingly, the study discusses the stages and main trends of artificial intelligence development. Depending on the scale of implementation, Georgia’s current trends in job cuts / disappearances along with automation are analysed and future prospects are assessed. The paper discusses the use and increased importance of artificial intelligence 4.0 industry in the context of pandemic restrictions in various sectors of the economy and assessed the role in the post-pandemic period. The paper uses both qualitative and quantitative research methods. Content analysis of the scientific literature, statistical indicators and practical examples of different countries and international organizations is provided. Studies of leading analytical institutions are also included to analyse the current situation and prospects for development.
Application of ICT tools in teaching American English for computer science students in the context of global challenges
Authors: Symonenko S V , Zaitseva N V , Vynogradova M S , Osadchyi V V , Sushchenko A V
Published: March 2021

The article deals with the urgent issue of American English learning for IT-professionals under challenging conditions of the changeable economic situation in the world. Some statistical data on global education trends and its analysis are given to confirm the topicality of the problem. State-of-the-art trends in foreign language teaching in the context of global challenges are presented. It is stated that informal education environments, distant learning platforms, virtual reality environments, artificial intelligence applications and collaboration platforms are to be mastered by Ukrainian undergraduates. Certain peculiarities of choosing and studying British and American English course by students of IT-specialities at three Ukrainian universities are given: the course choice procedure, the reasons for course preference, and the syllabus content. The best technologies, applications and tools for classroom activities and independent learning are substantiated, specific examples of their application for British and American English course learning are presented. The transferability of the skills inculcated in the course participants through implementation of the certain tools is founded.
PhD student training: principles and implementation
Authors: Panchenko L F , Korzhov H O , Kolomiiets T V , Yenin M N
Published: March 2021

The article deals with the problem of PhD student training. The Salzburg Principles about the improvement and quality assurance of doctoral programs at universities in every country from European University Association are analysed and materials of LERU on quality culture in Doctoral Education in Europe are used. The three focuses of the research component of doctoral program are proposed. The first focus relates to reproducible research principle. The second focus is related to the use of multivariate models of phenomena’s study and SEM methodology. The SEM methodology is mostly based on deductive logic, involves the preliminary construction of a structural model of the relationships between the variables in order to further check for consistency with the experimental data. The third focus combines qualitative and quantitative methods and the use of triangulation (data triangulation, investigation triangulation, theory triangulation etc.). The content of selected courses for doctorate students is proposed: Reproducible Research and Multivariate Methods in Scientific Research courses. The importance of courses related to the future career is demonstrated, in particular the career of academic researcher. Further development of our work is the creation of teaching and methodological support for selected course “Twitter for professional development of PhD students”.
Arrays of combined antennas excited by high-voltage bipolar pulses
Authors: Koshelev V I , Plisko V V
Published: March 2021

The main characteristics of the TEM antenna and the combined antenna (KA) with extended bandwidth are compared using numerical simulation. The influence of the high-voltage coaxial-strip junction on the KA characteristics is shown. The effective radiation potential is compared relative to the utmost one for high-power UWB radiation sources based on KA arrays, as well as single IRA, HIRA, TEM, and KA antennas.
Ultrawideband antenna arrays based on planar combined antennas for the frequency range of 3.1-10.6 GHz
Authors: Balzovsky E V , Buyanov Y I , Koshelev V I
Published: March 2021

The characteristics of ultrawideband antenna arrays, the element of which is a planar combined antenna with an operating frequency band of 3.1-10.6 GHz, are studied. The results of time-domain studies for a four-element linear array, as well as for a dual polarized module consisting of 2×2 antennas, are presented. The antenna array element is a combination of electric and magnetic radiators. The combined antenna is printed on a dielectric plate with a size of 20×30 mm.
Studying a low-temperature engine with external heat supply
Authors: Mekhtiyev A D , Yugay V V , Alkina A D , Neshina Y G , Kapanova D E
Published: March 2021

The article presents some results of studying the most optimal parameters of the displacer and the piston of a low-temperature engine with external heat supply to increase its efficiency when converting low-grade heat. The developed design of the engine does not have a displacer rod, which provides better sealing and reduces mechanical friction losses. Synchronization of the piston and the displacer movement is ensured by the permanent magnets interaction. The analysis of the results of computer simulation of the PV diagram with an increased diameter of the displacer in relation to the piston diameter plays a positive role in increasing the efficiency and power of the engine. Increasing the diameter of the displacer also leads to increasing the area of the PV diagram and its approach to the ideal thermal Stirling cycle. The simulation results show that increasing the diameter of the displacer above 17/1 does not lead to increasing the area of the PV diagram, and with a larger ratio, on the contrary, it reduces the parameters of the engine efficiency. Further increasing the diameter of the displacer is not advisable in terms of technical and economic ratios. The proposed engine with external heat supply is capable of converting heat from geothermal or industrial wastewater, as well as heated water using a solar collector.
Improving a device for identifying and marking parts of territory with chemical and radioactive contamination
Authors: Msallam M , Syryamkin V I
Published: March 2021

There is an urgent need to conduct a survey of areas exposed to chemical and radioactive contamination, assess the level of risk in these areas, and work on cleansing them of their remnants. Hence the need for advanced robots arises, where they should be capable of carrying out all hard tasks in different environments in all weather conditions and around the clock. In this article, we detail the components of an advanced device that consists of a robot capable of terrestrial-aerial movement and wirelessly connected with computerized workstations. Here we show the multiple advantages that the robot has compared to other previous models. We pay special attention to the technical vision system in the robot, and offer some proposals for the purpose of developing this system.
Development of a generalized physical and mathematical model of working substance processes in an axial turbine stage
Authors: Kalytka V A , Korovkin M V , Madi P Sh , Mekhtiyev A D , Bashirov A V , Mekhtiev R A
Published: March 2021

Methods of continuum mechanics and equilibrium thermodynamics are used to study a generalized physical and mathematical model of the processes of a working substance (steam, gas) moving in the flow part of an axial turbine stage in the nominal operating mode of the turbine. The mathematical description of the hydrodynamics and thermodynamics of the process is carried out for a one-dimensional model, based on the energy equation in thermomechanical form (the first law of thermodynamics in combination with the Bernoulli equation) for the gas (or steam) flow during its adiabatic (isentropic) expansion in the direction of the axis of the turbine stage. The energy equation is written taking into account both thermodynamic (due to the thermal movement of particles) and hydraulic pressure forces (due to the mechanical action of a continuous medium) of the working substance flow on the walls of the stage flow channel. Numerical calculation of flow rates and enthalpy losses on various elements of the stage (nozzle and working blades) is performed on the example of a model turbine with eight axial-type stages, under specified initial conditions of the process.
Determination of the test-samples electron density via dual energy computer tomography
Authors: Grigorieva A A , Bulavskaya A A , Miloichikova I A , Cherepennikov Yu M , Stuchebrov S G
Published: March 2021

In this work we determines electron density using data obtained via CT scanner with one radiation source operating in two modes: with 80 kV and 120 kV voltage. We perform tomography study of calibration phantom with predetermined electron densities. Single linear relationship between energy-subtracted Hounsfield unit and relative electron density is determined. Using determined relationship the relative electron densities of phantom calibration samples is calculated. The comparison of calculated and nominal values proves the possibility of the samples relative electron density determination using energy-subtracted Hounsfield unit with error less than 2%.
Application of a precision programmable DC power supply for spectrometer calibration
Authors: Kobelev D I , Jordan V I
Published: March 2021

The paper presents the circuitry solutions on the basis of which a precision programmable DC power supply was created and tested. The principle of operation of the DC power supply uses a high-precision method of controlling a pulse current stabilizer, based on the adaptation of the duty cycle of the pulse-width modulation (PWM) signal to control the inverter when the load mode changes. From the output of the inverter, the signal is converted by the rectifier into a DC signal with subsequent smoothing of the ripple and enters the load circuit. From a precision low-resistance shunt connected to the load circuit, the signal through the ADC in digital form enters the control unit (CU), implemented on the basis of FPGA, which has a embedded programme for controlling the voltage / current stabilization modes in the load circuit. In addition, the paper shows the use of a precision programmable DC power supply for solving the problem of calibrating the BTC-110S spectrometer. The block diagram of the test stand for spectrometer calibration is presented and relations for the correction of the recorded signals of the thermal radiation spectrum of the objects under study are derived.
Bladder muscle regeneration enhanced by sustainable delivery of heparin from bilayer scaffolds carrying stem cells in a rat bladder partial cystectomy model
Authors: Wang Chengyuan , Wang Hui , Guo Qianping , Ang Xiaojie , Li Bin , Han Fengxuan , Fu Yingxi , Chen Weiguo
Published: March 2021

In bladder tissue engineering, regeneration of muscle is of equal importance to epithelial regeneration. However, as yet there is no effective strategy for promoting bladder muscle regeneration. In this study we aim to promote bladder muscle regeneration by sustainably delivering heparin from a bilayer scaffold carrying stem cells. The bilayer scaffold [heparin–polycaprolactone (PCL)/bladder decellularized matrix (BAM) Hep-PB/PCL] comprises an electrospun layer (Hep-PB electrospun membrane) and a three-dimensional (3D) printed layer (PCL scaffold), fabricated via coaxial-electrospinning and 3D printing, respectively. Heparin was encapsulated into the core of the Hep-PB fibers with a core–shell structure to sustain its release. The morphology of the bilayer scaffold and the microstructure of the electrospun fibers were characterized. The release behavior of heparin from various electrospun membranes was evaluated. The role of Hep-PB in promoting myogenic differentiation of the adipose-derived stem cells (ADSCs) through sustainable release of heparin was also evaluated. After 7 d culture, Hep-PB/PCL scaffolds carrying ADSCs (defined as ASHP) were used for bladder reconstruction in a rat partial cystotomy model. The result shows that the PCL printed scaffold has ordered macropores (∼370 μm), unlike the compact microstructure of electrospun films. The Hep-PB membrane exhibits a sustained release behavior for heparin. This membrane also shows better growth and proliferation of ADSCs than the other membranes. The polymerase chain reaction results show that the expression of smooth muscle cell markers in ADSCs is enhanced by the Hep-PB scaffold. The results of retrograde urethrography and histological staining indicate that the bladder volume in the ASHP group recovers better, and the regenerated bladder muscle bundles are arranged in a more orderly fashion compared with the direct suture and bladder decellularized matrix groups. Therefore, findings from this study show that bladder muscle regeneration could be enhanced by bilayer scaffolds delivering heparin and carrying stem cells, which may provide a new strategy for bladder tissue engineering.
Beyond biomass to carbon fluxes: application and evaluation of a comprehensive forest carbon monitoring system
Authors: Zhou Yu , Williams Christopher A , Hasler Natalia , Gu Huan , Kennedy Robert
Published: March 2021

Accurate quantification of forest carbon stocks and fluxes over regions is needed to monitor forest resources as they respond to changes in climate, disturbance and management, and also to evaluate contributions of forest sector to the regional and global carbon balances. In previous work we introduced a national forest carbon monitoring system (NFCMS) that combines forest inventory data, satellite remote sensing of stand biomass and forest disturbances, and an ecosystem carbon cycle model to assess contemporary forest carbon dynamics at a 30 m resolution. In this study, we evaluate the NFCMS estimates of biomass and carbon fluxes with available data products for the Pacific Northwest (PNW) region, and then analyze the regional carbon balance over the period 1986–2010. The biomass estimates have good agreements with evaluation datasets (eMapR, NBCD2000, and Hagen2005) at regional and forest type levels, and at spatial scales of 1 km2 and larger. Regionwide, PNW forests acted as a stable net sink for atmospheric CO2 (18.5 Tg C yr–1) within forestlands. However, harvesting activities removed significant amounts of carbon, equating to over 75% of annual net carbon sink, though only 25% of this (∼3.5 Tg C yr–1) is emitted to the atmosphere within 50 years. Wildfires contributed modestly to carbon emissions in most years, however, the severe fires of 2002 and 2006 released 16.6 and 7.1 Tg C, respectively. The study demonstrates the potential of the NFCMS framework to serve as a candidate measuring, reporting and verification system, informed by field and remotely sensed inventories, and tracking the carbon balance of the forest sector across the United States.
Impact of climate change on soil nitric oxide and nitrous oxide emissions from typical land uses in Scotland
Authors: Medinets S , White S , Cowan N , Drewer J , Dick J , Jones M , Andrews C , Harvey D , Skiba U
Published: March 2021

Soil emissions of NO and N2O from typical land uses across Lowland and Highland Scotland were simulated under climate change conditions, during a short-term laboratory study. All locations investigated were significant sources of N2O (range: 157–277 µg N2O–N m−2 h−1) and low-to-moderate sources of NO emissions (range: 0.4–30.5 µg NO–N m−2 h−1), with a general tendency to decrease with altitude and increase with fertiliser and atmospheric N inputs. Simulated climate warming and extreme events (drought, intensive rainfall) increased soil NO pulses and N2O emissions from both natural and managed ecosystems in the following order: natural Highlands < natural Lowlands < grazed grasslands < natural moorland receiving high NH3 deposition rates. Largest NO emission rates were observed from natural moorlands exposed to high NH3 deposition rates. Although soil NO emissions were much smaller (6–660 times) than those of N2O, their impact on air quality is likely to increase as combustion sources of NO
x
are declining as a result of successful mitigation. This study provides evidence of high N emission rates from natural ecosystems and calls for urgent action to improve existing national and intergovernmental inventories for NO and N2O, which at present do not fully account for emissions from natural soils receiving no direct anthropogenic N inputs.
Enhancement of photocatalytic activity using ternary Au@Pt-TiO2/nano-GO heterojunction for environmental remediation and clean energy production
Authors: Ben Saber Nesrine , Mezni Amine , Alrooqi Arwa , Altalhi Tariq
Published: March 2021

In the present study, an attempt has been made to design ternary multifunctional nanocomposite photocatalyst based on Au@Pt-TiO2 core–shell nanoparticles anchored onto nano-graphene oxide (nano-GO) through facile one-pot solvothermal process. Evaluation of UV and visible light photocatalytic activities against MB dye and diuron pesticide decomposition, demonstrated a remarkable enhancement in photocatalytic performances, which indicates their potential as powerful photocatalyst. The enhancement of the photocatalytic activity of the designed ternary Au@Pt-TiO2/nano-GO could be attributed to the heterojunction structure and to the enhanced charge separation and light absorption of nano-GO and Au, Pt NPs. Before application, the ternary Au@Pt-TiO2/nano-GO photocatalyst was fully characterised (structural, morphology and composition) using powerful instruments including x-ray diffraction powder (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). The optical response was investigated using UV-Visible spectrophotometer. The ternary Au@Pt-TiO2/nano-GO photocatalyst exhibits high crystallinity and high purity with uniform behaviour on size and shape. The hybrid Au@Pt-TiO2 nanoparticles were found to be well dispersed on nano-GO surface, which make this heterojunction very efficient for photocatalytic applications.
Improving deconvolution methods in biology through open innovation competitions: an application to the connectivity map
Authors: Blasco Andrea , Natoli Ted , Endres Michael G , Sergeev Rinat A , Randazzo Steven , Paik Jin H , Macaluso N J Maximilian , Narayan Rajiv , Lu Xiaodong , Peck David , Lakhani Karim R , Subramanian Aravind
Published: March 2021

Motivation

Do machine learning methods improve standard deconvolution techniques for gene expression data? This article uses a unique new dataset combined with an open innovation competition to evaluate a wide range of approaches developed by 294 competitors from 20 countries. The competition’s objective was to address a deconvolution problem critical to analyzing genetic perturbations from the Connectivity Map. The issue consists of separating gene expression of individual genes from raw measurements obtained from gene pairs. We evaluated the outcomes using ground-truth data (direct measurements for single genes) obtained from the same samples.

Results

We find that the top-ranked algorithm, based on random forest regression, beat the other methods in accuracy and reproducibility; more traditional gaussian-mixture methods performed well and tended to be faster, and the best deep learning approach yielded outcomes slightly inferior to the above methods. We anticipate researchers in the field will find the dataset and algorithms developed in this study to be a powerful research tool for benchmarking their deconvolution methods and a resource useful for multiple applications.

Availability and implementation

The data is freely available at clue.io/data (section Contests) and the software is on GitHub at https://github.com/cmap/gene_deconvolution_challenge

Supplementary information

Supplementary data are available at Bioinformatics online.
Inflammation and reproductive function in women with polycystic ovary syndrome
Authors: Velez Leandro M , Seldin Marcus , Motta Alicia B
Published: March 2021

Polycystic ovary syndrome (PCOS) is one of the most frequent endocrinopathies, affecting 5–10% of women of reproductive age, and is characterized by the presence of ovarian cysts, oligo, or anovulation, and clinical or biochemical hyperandrogenism. Metabolic abnormalities such as hyperinsulinemia, insulin resistance, cardiovascular complications, dyslipidemia, and obesity are frequently present in PCOS women. Several key pathogenic pathways overlap between these metabolic abnormalities, notably chronic inflammation. The observation that this mechanism was shared led to the hypothesis that a chronic inflammatory state could contribute to the pathogenesis of PCOS. Moreover, while physiological inflammation is an essential feature of reproductive events such as ovulation, menstruation, implantation, and labor at term, the establishment of chronic inflammation may be a pivotal feature of the observed reproductive dysfunctions in PCOS women. Taken together, the present work aims to review the available evidence about inflammatory mediators and related mechanisms in women with PCOS, with an emphasis on reproductive function.
Novel approaches to mechanism-based atrial fibrillation ablation
Authors: Quintanilla Jorge G , Shpun Shlomo , Jalife José , Filgueiras-Rama David
Published: March 2021

Modern cardiac electrophysiology has reported significant advances in the understanding of mechanisms underlying complex wave propagation patterns during atrial fibrillation (AF), although disagreements remain. One school of thought adheres to the long-held postulate that AF is the result of randomly propagating wavelets that wonder throughout the atria. Another school supports the notion that AF is deterministic in that it depends on a small number of high-frequency rotors generating three-dimensional scroll waves that propagate throughout the atria. The spiralling waves are thought to interact with anatomic and functional obstacles, leading to fragmentation and new wavelet formation associated with the irregular activation patterns documented on AF tracings. The deterministic hypothesis is consistent with demonstrable hierarchical gradients of activation frequency and AF termination on ablation at specific (non-random) atrial regions. During the last decade, data from realistic animal models and pilot clinical series have triggered a new era of novel methodologies to identify and ablate AF drivers outside the pulmonary veins. New generation electroanatomical mapping systems and multielectrode mapping catheters, complimented by powerful mathematical analyses, have generated the necessary platforms and tools for moving these approaches into clinical procedures. Recent clinical data using such platforms have provided encouraging evidence supporting the feasibility of targeting and effectively ablating driver regions in addition to pulmonary vein isolation in persistent AF. Here, we review state-of-the-art technologies and provide a comprehensive historical perspective, characterization, classification, and expected outcomes of current mechanism-based methods for AF ablation. We discuss also the challenges and expected future directions that scientists and clinicians will face in their efforts to understand AF dynamics and successfully implement any novel method into regular clinical practice.
Myocardin-related transcription factor A regulates integrin beta 2 transcription to promote macrophage infiltration and cardiac hypertrophy in mice
Authors: Liu Li , Zhao Qianwen , Kong Ming , Mao Lei , Yang Yuyu , Xu Yong
Published: March 2021

Aims

Macrophage-mediated inflammatory response represents a key pathophysiological process in a host of cardiovascular diseases including heart failure. Regardless of aetiology, heart failure is invariably preceded by cardiac hypertrophy. In the present study, we investigated the effect of macrophage-specific deletion of myocardin-related transcription factor A (MRTF-A) on cardiac hypertrophy and the underlying mechanism.

Methods and results

We report that when subjected to transverse aortic constriction (TAC), macrophage MRTF-A conditional knockout (CKO) mice developed a less severe phenotype of cardiac hypertrophy compared to wild-type (WT) littermates and were partially protected from the loss of heart function. In addition, there was less extensive cardiac fibrosis in the CKO mice than WT mice following the TAC procedure. Further analysis revealed that cardiac inflammation, as assessed by levels of pro-inflammatory cytokines and chemokines, was dampened in CKO mice paralleling reduced infiltration of macrophages in the heart. Mechanistically, MRTF-A deficiency attenuated the expression of integrin beta 2 (ITGB2/CD18) in macrophage thereby disrupting adhesion of macrophages to vascular endothelial cells. MRTF-A was recruited by Sp1 to the ITGB2 promoter and cooperated with Sp1 to activate ITGB2 transcription in macrophages. Administration of a CD18 blocking antibody attenuated TAC-induced cardiac hypertrophy in mice. Interaction between MRTF-A and the histone demethylase KDM3A likely contributed to IGTB2 transcription and consequently adhesion of macrophages to endothelial cells.

Conclusions

Our data suggest that MRTF-A may regulate macrophage trafficking and contribute to the pathogenesis of cardiac hypertrophy by activating ITGB2 transcription.
Free fatty acid receptor 4 responds to endogenous fatty acids to protect the heart from pressure overload
Authors: Murphy Katherine A , Harsch Brian A , Healy Chastity L , Joshi Sonal S , Huang Shue , Walker Rachel E , Wagner Brandon M , Ernste Katherine M , Huang Wei , Block Robert C , Wright Casey D , Tintle Nathan , Jensen Brian C , Wells Quinn S , Shearer Gregory C , O’Connell Timothy D
Published: March 2021

Aims

Free fatty acid receptor 4 (Ffar4) is a G-protein-coupled receptor for endogenous medium-/long-chain fatty acids that attenuates metabolic disease and inflammation. However, the function of Ffar4 in the heart is unclear. Given its putative beneficial role, we hypothesized that Ffar4 would protect the heart from pathologic stress.

Methods and results

In mice lacking Ffar4 (Ffar4KO), we found that Ffar4 is required for an adaptive response to pressure overload induced by transverse aortic constriction (TAC), identifying a novel cardioprotective function for Ffar4. Following TAC, remodelling was worsened in Ffar4KO hearts, with greater hypertrophy and contractile dysfunction. Transcriptome analysis 3-day post-TAC identified transcriptional deficits in genes associated with cytoplasmic phospholipase A2α signalling and oxylipin synthesis and the reduction of oxidative stress in Ffar4KO myocytes. In cultured adult cardiac myocytes, Ffar4 induced the production of the eicosapentaenoic acid (EPA)-derived, pro-resolving oxylipin 18-hydroxyeicosapentaenoic acid (18-HEPE). Furthermore, the activation of Ffar4 attenuated cardiac myocyte death from oxidative stress, while 18-HEPE rescued Ffar4KO myocytes. Systemically, Ffar4 maintained pro-resolving oxylipins and attenuated autoxidation basally, and increased pro-inflammatory and pro-resolving oxylipins, including 18-HEPE, in high-density lipoproteins post-TAC. In humans, Ffar4 expression decreased in heart failure, while the signalling-deficient Ffar4 R270H polymorphism correlated with eccentric remodelling in a large clinical cohort paralleling changes observed in Ffar4KO mice post-TAC.

Conclusion

Our data indicate that Ffar4 in cardiac myocytes responds to endogenous fatty acids, reducing oxidative injury, and protecting the heart from pathologic stress, with significant translational implications for targeting Ffar4 in cardiovascular disease.