bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing primary school students’ reasoning ability on the topic of plane geometry by using hawgent dynamic mathematics software
Authors: Chotimah S , Wijaya T T , Aprianti E , Akbar P , Bernard M
Published: October 2020

Plane geometry is one of the topics taught in middle school that is difficult to understand. Mostly, teachers use the traditional teaching method when explaining this concept which is why most students only memorize the formula for plane geometry without knowing how the formula is formed. These factors affect students’ reasoning ability. According to the information above, there are two main purposes of this research. The first purpose is to know how significant is the effect of Hawgent dynamic mathematics software on primary school students’ reasoning ability and the second purpose is to compare primary school students’ reasoning ability between the experimental and controlled classes. The sample of this research is 30 5th grade students in one of the primary schools in Cimahi city, Indonesia in the year of 2019/2020. The data collection will be done by using the pre-test and post-test to compare the primary school students’ reasoning ability in the experimental and controlled class. The data will be processed by using SPPS 16 and Microsoft excel. The result of this research is that there is an effect in students’ reasoning when using Hawgent dynamic mathematics software as a learning media and comparing the reasoning ability of the controlled and experimental class on the topic of plane geometry.
Microsoft Excel VBA on mathematical resilience of primary school teacher education students
Authors: Ruqoyyah S , Murni S , Fasha L H
Published: October 2020

This research is motivated by the low student mathematical resilience. The purpose of this study is to look at the achievement of mathematical resilience of students who obtain learning using Microsoft Excel VBA with those using conventional learning. This study uses a quasi-experimental method with a non-equivalent pretest and posttest control group design. The subjects of this study were 70 second semester elementary school teacher candidates at IKIP Siliwangi. The instruments in this study used non-tests in the form of questionnaires and interviews. The results show that, 1) the achievement of mathematical resilience of students who get learning using Microsoft Excel VBA is better than those using conventional learning; 2) students who learn with Microsoft Excel VBA tend to be able to overcome difficulties if given difficult math problems, anxiety and fear in working on math problems are reduced, and more confident in expressing mathematical opinions/ideas; 3) mathematical resilience is not an instant thing to change so it needs environmental support so that students’ mathematical resilience becomes better.
Increasing students’ mathematical communication skills by applying probing-prompting learning model based on Belu culture artefact
Authors: Dominikus Wara Sabon , Nenohai Juliana M H , Hale Marlenci
Published: October 2020

This research is a Classroom Action Research that aims to improve students’ mathematical communication skills through a probing-prompting learning model based on Belu culture artefact. The research subjects were all students of class VIII-A at Atambua State Junior High School 2 with totaling 39 students. The research was conducted in two cycles, that each cycle consists of two lessons in topic cube and cuboid. Data were collected using observation, test, and documentation techniques. The data were analyzed descriptively. The results show that the students’ mathematical communication skills increase from the first cycle to the second cycle after applying a probing-prompting learning model based on Belu culture artefacts. It is indicated by as much as 72.22% of students experiencing an increase in the total score of aspects of mathematical communication skills. Also, the implementation of learning reached 83.33% in the excellent category. Based on the observation results, students’ mathematical communication skills increase from 74,13% (good category) on the first cycle to 85.68% (good category) on the second cycle. It can be concluded that the application of probing-prompting based on Belu culture artefacts can improve students’ mathematical communication skills.
Ethnomathematics in Boti tribe culture and its integration
Authors: Dosinaeng W B N , Lakapu M , Leton S I
Published: October 2020

The development of ethnomathematics is an indication of an increase in awareness of the importance of learning mathematics in culture and involves cultural aspects in mathematics learning in schools. As one of the ancient tribes in Timor,BotiTribe is almost unapproachable by the modern culture. Learning mathematics based onBoticulture will help students learn mathematics realistically and also introduceBoticulture to more people. The present research claims a qualitative approach with an ethnographic design that aims to explore the mathematical elements found in the culture ofBotiTribe. The subject of this research is theBoti DalamTribe, which implementsBoticultural traditions in everyday life. The objects examined in this study are the calendar ofBotiTribe,lopo, and the typical woven fabric ofBotiTribe. The results show that the concepts of numbers and their operations, geometry, and algebra are apparent in the culture ofBotiTribe. Also, mathematical skills such as representation, spatial, making connections, and problem-solving skills can be developed based on mathematical elements inBotiTribe culture. This study can be used by teachers to create innovative mathematics learning models using ethnomathematics approaches based onBoticulture.
Students’ activeness in jigsaw type cooperative learning and rank 1 games on sets topic
Authors: Nurwahidayati N , Qohar A
Published: October 2020

Student activity in learning is essential so that learning objectives can be achieved. This study aims to describe the activeness of students in the application of Jigsaw cooperative learning and Rank 1 games on the topic of sets. This research was conducted at Universitas Negeri Malang school year of 2019/2020. The method used is quantitative descriptive. In this study applied Jigsaw type cooperative learning and Rank 1 games. At the same time, the research subjects were the 5th-semester students who were taking the Social Mathematics course, in the topic of mathematical sets, Undergraduate Mathematics Education Program of Universitas Negeri Malang year 2017 with a total of 30 students. Based on the analysis results of students’ activeness observation, an average percentage of 91.83% was obtained. It shows that the students’ activeness in the Social Mathematics course, especially on the topic of sets, was categorized as excellent.
Students’ environment awareness through scientific approach in mathematics instruction
Authors: Mumu J , Prahmana R C I , Sabariah V , Tanujaya B
Published: October 2020

The purpose of this study is to develop learning designs that incorporate environmental contexts into mathematics learning. The method used is a qualitative method using a literature review approach. The selection of research objects and literature is achieved through purposeful sampling techniques and by employing data search engines. Mathematics research is being designed using a global context with a theoretical approach. The results have shown that there are different environmental contexts, especially those related to Papua. These contexts can be used in mathematical instruction. Mathematics instruction using this context is expected to develop students’ awareness of the environment.
Students’ thinking: arithmetic in solving a mathematical problem
Authors: Wahyuni R , Herman T , Fatimah S
Published: October 2020

The students in secondary school have difficulties making the transition from arithmetic to algebra. In order to obtain the students approach while solving the problem, the students are given a mathematical problem that can be solved by using arithmetic or algebraic. This study is implemented in class grade 7, and they have learnt the introduction of algebra. This research was using a qualitative method with description design. Six students who are a participant in this study have excellent communication and give different strategies while solving the problems. The students are given a mathematical test problem, and then the students are interviewed based on their answer sheet in the test in order to get in-depth information from their strategies. From the result of students are given, we acquire that the arithmetical approach is dominated in their strategy to solve the problem. Many of the students do not realize the using of the quantities of the unknown in that problem. Arithmetic is the approach that accomplished to coverage the students to solve the problem and the students just do numbers and operation, and focus in numeric answer. Most of the student in a secondary school in seventh grade is direct think arithmetically than algebraically.
Students’ mathematical problem solving ability on the subject of function limits
Authors: Mauladaniyati R , Ramadina I , E Cahya MA
Published: October 2020

This research is a qualitative descriptive study. The research subjects were three students of class XI MA Ibad Arrahman Pandeglang Regency consisting of students who have high, medium and low abilities. The purpose of this study is to analyze the students’ mathematical problem-solving abilities on material limit functions. This ability is expected to be mastered by students to solve mathematical problems correctly and adequately. Data collection is done through the provision of problem-solving tests and observations then triangulation techniques are carried out to obtain valid data. The results of this study are students who are highly capable of having good mathematical solving abilities. Students who are capable of being mathematical problem-solving abilities are quite good. It’s just not thorough or errors in the operation of numbers. In contrast, students with low ability have poor mathematical problem-solving skills because they cannot solve problems completely.
Effectiveness of scaffolding-based interactive teaching materials: reflective thinking ability in prospective teacher mathematics
Authors: Nindiasari H , Yuhana Y , Novaliyosi  , Sukirwan
Published: October 2020

This research is motivated by the importance of reflective thinking skills in prospective teacher students. This ability is felt to be lacking especially in prospective teacher students at one of the state universities in Banten Province, even though they need this ability to train their students. One of the efforts given is interactive scaffolding-based teaching materials. Teaching materials are developed by using computer technology. This study uses a quasi-experimental research method. The population of this study is a student candidate for mathematics teacher at a state university in Banten with a sample of 2 classes taken by students who are taking courses related to learning. The instrument used was a test of reflective thinking ability in the form of a matter of description. Processing data using non-parametric U-Mann Whitney statistical tests. The results of this study concluded that the reflective thinking ability of pre-service mathematics teachers of students with the application of learning through interactive Scaffolding teaching materials is better than that applied in learning with teaching materials in the form of PPT. This conclusion is indicated by the data value of Asym. Sig = 0.278 is greater than 1 / 2∝ = 0.025
The influence of problem posing learning on mathematical solution ability of junior high school
Authors: Cahyani A , Putri Z R , Fitriani N
Published: October 2020

This study aims to determine the influence of learning problems posing to the mathematical problem-solving skills of class VIII students. The approaches and methods used in this study are quantitative approaches and experimental methods. The design in this research is pre-experimental with form one group pre-tests post-test design. This study was conducted at Junior high School Al Islam Cikampek by taking one class as a sample of research, class VIII C which amounted to 40 students. Sampling using purposive sampling techniques. The instruments in this study used a 4-question description test related to mathematical problem-solving skills with surface area material, prism volume, and pyramid. There are three phases in this research, the pre-test is done to know the initial ability to solve the student’s mathematical problem before given treatment. After being given a pre-test, researchers give treatment by giving teaching using the model problem posing. After treatment, the researchers conducted a post-test to determine the final ability to solve students’ mathematical problems. Based on the analysis results of the test-T for two dependent samples showed there is the influence of learning problems posing to the ability to solve the mathematical problem of class VIII students.
Increasing mathematical understanding ability using quantum teaching hypnoteaching-based in elementary school teacher education students
Authors: Novianti I , Mulyaning E C
Published: October 2020

The absence of empirical understanding of the understudies is the product of less certainly applicable learning frameworks. Quantum Showing depending upon hypnoteching is a finding that is focused on the advancement of understudies of scientific understanding because the information can be explained by means of this model in an effective and competent manner and also because the structures of hypnoteching are anxious to learn while research. This thesis is an exploratory analysis. There are 50 semester understudies from ESTE in this study which have been haphazardly selected. A Quantum Display class is given based on hypnoteaching (QTH), and standard training (OL) is given in a control class. The methods used are: study, interpretation sheet and meeting guide. Knowledge analysis techniques in this study use t-test. The consequence of this research is that QTH testing has a better theoretical perception than OL analysis. Because of the degree of early (large, medium and small) numerical ability, medium and low capacities understudies have seen major differences, but not for high capability understudies. In view of the reaction that occurred during the study, understudies with QTH displayed a movement and stronger ability than OL.
The 5E learning cycle model in an effort to foster students’ mathematical communication skills viewed from academic level
Authors: Zetriuslita  , Uswatun
Published: October 2020

This study aims to analyze the effectiveness of the 5E Learning Cycle model in developing mathematical communication skill of junior high school students. This research is Quasi Experiment. The design of this study is nonequivalent control group design. The population of this research is all eighth grade students of SMP Negeri 5 Pekanbaru. Samples were selected using purposive sampling. Class VIII.2 as an experimental class with 36 students and class VIII.1 as a control class with 36 students. Data collection instruments are tests and observation sheets. The test is used to see the score of students’ mathematical communication skills to be analyzed with descriptive statistics and inferential analysis. Observation is used to see the implementation of the 5E Learning Cycle model on teacher and student activities. The data analysis technique uses percentages and t-test, and the observations are analyzed in percentages and categorized qualitatively. The findings showed that there is a significant effect of the LC 5E model on the mathematical communication skills of Grade VIII students of SMP Negeri 5 Pekanbaru. Especially for high academic level, there is no significant effect of the 5E Learning Cycle model on the mathematical communication skill.
Spatial vector autoregressive model with calendar variation and its application
Authors: Sumarminingsih E , Setiawan S , Suharsono A , Ruchjana B N
Published: October 2020

The Vector Autoregressive (VAR) model can be used to determine the relationships among several interacting variables in time series data. While the Spatial VAR (SpVAR) model was developed to accommodate temporal dynamics and spatial dynamics simultaneously. Time series data in economics are often influenced by events such as holidays occurring based upon the lunar calendar. Hence, it happens on different dates and months each year. Such holidays are called calendar variations. The purpose of this paper is to develop a SpVAR model with the effects of calendar variations, discuss the parameter estimation method and apply the model to Inflation and Money Supply data in three cities in West Java, Indonesia. Parameters are estimated by using Full Information Maximum Likelihood. The result for the application is there is a relationship between Money Supply in Cirebon and Inflation in Bandung and Tasikmalaya. Also, there are effects of calendar variation on Inflation and Money Supply in all three cities.
Digital literacy skills of math students through e-learning in COVID-19 era: a case study in Universitas Riau
Authors: Zulkarnain Z , Heleni S , Thahir M
Published: October 2020

The phenomenon of using social media as online media is getting more massive this decade. Young people as a millennial generation are the biggest users in the use of social media today. Research on digital literacy is still rare, especially in Indonesia. Based on this phenomenon, this study aims to map students’ digital mathematical literacy through e-learning in the Covid-19 era. This research uses a quantitative approach with a case study method. Informants were used as research samples of 8 postgraduate students at Riau University. Student digital literacy ability data was collected through online questionnaires using Google Form, then analyzed descriptively using SPSS Program version 23.00 for Windows. The findings obtained in this study indicate the importance of digital literacy capabilities that have a positive impact on knowledge, understanding and skills in using media, especially social media, which is now often used as a source of information by the public, especially by students. Seeing the results of the study, researchers recommended the need for universities or leaders so that students can improve their digital literacy abilities.
The improvement of students’ mathematics critical thinking abilities in topic prism and pyramid by using the Problem Posing approach
Authors: Supandi S , Ariyanto L , Kusumaningsih W , Handayanto A , Sarra R R
Published: October 2020

This study aims to determine the increase in mathematical critical thinking skills in high school junior students by applying the Problem Posing approach. One hundred ninety-two students were sampled, divided into six classes. Samples from the study were two classes (one as the experiment and the other as the control class). The results of this study indicate that 1) based on the average post-test score, the experimental class is better than the control class; 2) based on the results of N-Gain, the experimental class is better than the control class, even though both are in the medium category; and 3) based on the right-hand t-test, it is proven that the mathematical critical thinking ability of the experimental class is better than the control class. So, it can be concluded that Problem Posing learning in students can improve mathematics critical thinking skills.
Perfect colouring of the graph with its kinds
Authors: Bhange A A , Bhapkar H R
Published: October 2020

The Perfect colouring (jp) of a graph is an assignment of colours to all elements (vertices, edges, and regions) of the graph such that no two adjoint elements receive the same colour. In this paper, we determined the tight bounds of perfect colouring as/“(G) </P(G) </“(G) + 4, where/“(G) is total colouring of the graph G. Depending on these bounds, the perfect colouring is divided into five different kinds, and the results of these for some standard graphs are presented in the paper.
Does students’ logical-mathematical intelligence correlate to mathematics communication skills on a linear system with three variables problems?
Authors: Suwarno S , Nisa F B , Mukhlis M
Published: October 2020

Logical-mathematical intelligence has affected the ability to analyze in a problem, create mathematical formulas or patterns, and communicate mathematical problem-solving. In Class X IPA, there are some students with a high level of logical-mathematical intelligence but are relatively low in mathematical communication, especially on solving a three-variable linear equation system problem. This study aims to investigate the correlation of logical-mathematical intelligence to students’ mathematical communication skills of students at class X SMA Jenggawah Jember. The population in this study are 144 students of class X IPA, in the 2019/2020 academic year. This study uses the Cluster Random Sampling technique involve 64 students as samples. This study used a logical-mathematical intelligence questionnaire consisting of 22 items and three mathematical communication skills essay tests. This study uses descriptive and inferential data analysis in which the hypothesis test uses a simple linear regression test. The descriptive analysis reports the percentage of each category in terms of logical-mathematical intelligence. It also reports the percentage of each category in terms of mathematical communication skills. Based on the inferential analysis with significant level 0.05, it can be concluded that logical-mathematical intelligence correlates with the mathematical communication skills in the material.
Effectivity and students’ satisfaction to a tutorial in statistics through a webinar
Authors: Sugilar S
Published: October 2020

The aim of the article was a review of the tutorials through webinars on Educational Statistics courses for students of the Master’s Degree in Basic Education of Universitas Terbuka. The focus of the research was students’ views on the effectiveness and satisfaction of the webinar in terms of engagement, complexity, and task orientation. The respondents of the study consisted of 74 students of the master’s degree program in primary education. Data analysis used PLS-SEM to predict causal relationships among the variables understudied. The results showed that: 1) engagement gave an effect to effectivity, but did not give an effect to satisfaction, 2) complexity brought an effect to satisfaction but did not give an effect to effectivity, and 3) task orientation gave an effect to effectivity and satisfaction. Recommendations: 1) to increase the effectiveness of mathematics tutoring through webinars, it is necessary to increase student engagement and time efficiency of learning activities, and 2) to increase satisfaction with mathematics tutoring through webinars, it is necessary to improve the ease of implementing webinars (technical and procedures) and efficiency of learning time.
The effect of Learning Starts with a Question (LSQ) through WhatsApp media in the COVID-19 pandemic era in the mastery of Differential Equations
Authors: Sulistyo L , Junaedi I
Published: October 2020

This research aims to prove the effeciveness f learning with LSQ during the COVID-19 pandemic. The research method used is a quasi experiment by comparing face-to-face learning and LSQ learning using WhatsApp. The instrument used is a differential equation test. The results is online LSQ using WhatApps can improve student learning outcomes compared to face-to-face learning. Interaction between students and lecturers during online learning occurs interactively so that student motivation to learn also increases. Furthermore, the application of LSQ needs to be developed in other courses and different engineering fields. The results of this study indicate that LSQ learning with WhatsApps Media can be used as an alternative solution in learning in the COVID-19 Pandemic Era.
Blended learning: a strategy of current mathematics learning
Authors: Sari R M M , Priatna N
Published: October 2020

This article aims to provide an overview of a mathematical learning strategy that can be used in facing the industrial revolution 4.0 in the education world of Indonesia. The background of this article is to explain one of today’s learning strategies, Blended Learning. This article uses analytical and literature review methods. That is, in this case, the increased information and communications technology usage in the learning process in Indonesia is analyzed following the existing circumstances based on relevant books, articles, journals, and other sources. This article examines the characteristics of the blended learning strategy, the procedures for implementing blended learning, and the philosophical foundation of blended learning in mathematics learning. The results from reviewing the articles obtained show that the blended-learning strategy is suitable to use in mathematics learning since students, by use blended-learning strategy, may evaluate their skills themselves as well as determine their learning speed.
Educational apps for a prospective mathematics teacher in probability course
Authors: Ariyanto L , Supandi S , Kusumaningsih W , Silviani M T
Published: October 2020

This research aims to develop an Android Package Kit (APK) to improve college students’ mathematical critical thinking skills. The APK developed does not only contain a summary of the material and evaluation questions, but also contains contextual animation, education games, appropriate reference links for supplements and college student enrichment, and online discussion groups in which some teachers can provide feedback to discuss or lead the course of discussion in study groups. This research belongs to development research refers to ADDIE. In the analysis, the design and development stage conducts several activities to prepare the design and APK devices until the revision. At the implementation and evaluation stage, the effectiveness of learning using APKs was seen using a quasi-experimental research design with pre-test post-test control group design. This study found a feature that is different from other similar applications, the “join” and “search” features. Based on testing from media experts and material experts, it shows that the design and APK devices are learning media that are suitable for use by students, as well as the average of critical thinking skills the experimental class is better than the control class.
Problem-based learning flipped classroom design for developing higher-order thinking skills during the COVID-19 pandemic in geometry domain
Authors: Yurniwati Y , Utomo E
Published: October 2020

Higher-order thinking skills are skills demanded by society for the 21st century and ability that is required to succeed academically and in the work environment. As one of the learning objectives in the 21st century, higher-order thinking skills developed since in primary education until higher education. A variety of learning methods and learning media developed to develop this thinking ability. The purpose of this study is to design a learning model to improve the Higher Order Thinking Skills in geometry. It is the literature review study based on related articles and books. The sources were analyzed to formulate a useful learning model. The results show that Problem Based Learning Flipped Classroom improve students’ Higher Order Thinking Skills, and appropriate to be used during The Covid-19 Pandemic. Also, Problem Based Learning Flipped Classroom provides students the opportunity to increase self-directed learning and collaboration.
Case-based games learning strategies to improve conceptual understanding in mathematics
Authors: Asfar A M I T , Asfar A M I A
Published: October 2020

Case-Based Games Learning (CBGL) is a strategy of active learning in which the students implement knowledge and analytical skill related to the real complex situation (contextual) and relevant with subject lessons. Give case-based task or question routinely can help students to solve case-based mathematics problems. This study aims to analyze the effectiveness of CBGL using Quizizz dan Case Base Learning (CBL) without Quizizz based on students’ conceptual understanding in mathematics by finding out the percentage of the correct answer. Students were grouping by using a purposive sampling method based on the conceptual understanding indicator. The result of this study is the average conceptual understanding CBGL using Quizizz application strategy is more effective than CBL without Quizizz application in evaluating student work results quickly, precisely, and accurately. Therefore the use of Quizzes application with CBGL was more effective than CBL in assessing the work result quickly, right, and accurately.
How group theory and school mathematics are connected: an identification of mathematics in-service teachers
Authors: Pramasdyahsari A S , Setyawati R D , Albab I U
Published: October 2020

The purpose of the article is to describe the IMTs’ identified mathematical connection between group theory and school mathematics curriculums in Indonesia. The data was gathered from the IMTs who involved in the Teachers Professional Training (TPT) program. The study used the concept-by-concept framework through a descriptive qualitative approach, to analyze how IMT’s connect the group theory and school mathematics contents. The results reveal that the IMTs’ identified connection classified as a concept by concept which align to the comparison through common features categorize. Even though the IMTs have the teaching experience both junior and senior high school, however; the identified connection tends to be too general based on the curriculum on school mathematics. The teaching experience that the subjects have, seems to affect the way the subject created the connections. Nevertheless, it shows that the IMTs could recall and create the mathematical connection between group theory and school mathematics with adjusted to the school curriculum. For mathematics teachers’ education programs, the results could be a consideration for designing a mathematics school textbook which is strongly supported by group theory concept as university mathematics.
Protrusion mechanism study in sipunculid worms as model for developing bio-inspired linear actuators
Authors: Filogna Silvia , Iacovacci Veronica , Vecchi Fabrizio , Musco Luigi , Menciassi Arianna
Published: October 2020

The invertebrates ability to adapt to the environment during motion represents an intriguing feature to inspire robotic systems. We analysed the sipunculid species Phascolosoma stephensoni (Sipunculidae, Annelida), and quantitatively studied the motion behaviour of this unsegmented worm. The hydrostatic skeleton and the muscle activity make the infaunal P. stephensoni able to extrude part of its body (the introvert) from its burrow to explore the environment by remaining hidden within the rocky substrate where it settled. The introvert protrusion is associated with changes in the body shape while keeping the overall volume constant. In this study, we employed a marker-less optical tracking strategy to quantitatively study introvert protrusion (i.e. kinematics, elongation percentage and forces exerted) in different navigation media. When P. stephensoni specimens were free in sea water (outside from the burrow), the worms reached lengths up to three times their initial ones after protrusion. Moreover, they were able to elongate their introvert inside a viscous medium such as agar-based hydrogel. In this case, the organisms were able to break the hydrogel material, exerting forces up to 3 N and then to navigate easily inside it, producing stresses of some tens of kPa. Our measurements can be used as guidelines and specifications to design and develop novel smart robotic systems.
Understanding spatial variability of forage production in California grasslands: delineating climate, topography and soil controls
Authors: Liu Han , Jin Yufang , Roche Leslie M , O’Geen Anthony T , Dahlgren Randy A
Published: October 2020

Rangelands are a key global resource, providing a broad range of ecological services and economic benefits. California’s predominantly annual rangelands cover ∼12% of the state’s land area, and the forage production is highly heterogeneous, making balancing economic (grazing), conservation (habitat) and environmental (erosion/water quality) objectives a big challenge. Herein, we examined how climate and environmental factors regulate annual grassland forage production spatially across the state and among four ecoregions using machine learning models. We estimated annual forage production at 30 m resolution over a 14 year period (2004–2017) using satellite images and data fusion techniques. Our satellite-based estimation agreed well with independent field measurements, with aR2of 0.83 and RMSE of 682 kg ha−1. Forage production (14 year average) showed large spatial variability (2940 ± 934 kg ha-1yr-1; CV = 35%) across the study area. The gradient boosted regression tree with 11 feature variables explained 67% of the variability in forage production across the state. Precipitation amount, especially in November (germination) and April (rapid growth), was found as the dominant driver for spatial variation in forage production, especially in drier ecoregions and during drier years. Seasonal distribution of precipitation and minimum air temperature showed a relatively stronger control on forage production in wetter regions and during wet years. Additionally, solar energy became more important in wetter ecoregions. Drought reduced forage production from the long-term mean, i.e. a 33% ± 19% decrease in production (2397 ± 926 kg ha-1yr-1; CV = 38%) resulting from a 29% ± 5% decrease in precipitation. The machine learning based spatial analysis using ‘big data’ provided insights on impacts of climate and environmental factors on forage production variation at various scales. This study demonstrates a cost-effective approach for rapid mapping and assessment of annual forage production with the potential for near real-time application.
Recent trends in gross primary production and their drivers: analysis and modelling at flux-site and global scales
Authors: Cai Wenjia , Prentice Iain Colin
Published: October 2020

Gross primary production (GPP) by terrestrial ecosystems is the largest flux in the global carbon cycle, and its continuing increase in response to environmental changes is key to land ecosystems’ capacity to offset anthropogenic CO2 emissions. However, the CO2- and climate-sensitivities of GPP vary among models. We applied the ‘P model’—a parameter-sparse and extensively tested light use efficiency (LUE) model, driven by CO2, climate and remotely sensed greenness data—at 29 sites with multi-year eddy-covariance flux measurements. Observed (both positive and negative) GPP trends at these sites were predicted, albeit with some bias. Increasing LUE (due to rising atmospheric CO2 concentration) and green vegetation cover were the primary controls of modelled GPP trends across sites. Global GPP simulated by the same model increased by 0.46 ± 0.09 Pg C yr–2 during 1982–2016. This increase falls in the mid-range rate of simulated increase by the TRENDY v8 ensemble of state-of-the-art ecosystem models. The modelled LUE increase during 1900–2013 was 15%, similar to a published estimate based on deuterium isotopomers. Rising CO2 was the largest contributor to the modelled GPP increase. Greening, which may in part be caused by rising CO2, ranked second but dominated the modelled GPP change over large areas, including semi-arid vegetation on all continents. Warming caused a small net reduction in modelled global GPP, but dominated the modelled GPP increase in high northern latitudes. These findings strengthen the evidence that rising LUE due to rising CO2 level and increased green vegetation cover (fAPAR) are the main causes of increasing GPP, and thereby, the terrestrial carbon sink.
Pesticide application rates and their toxicological impacts: why do they vary so widely across the U.S.?
Authors: Tao Mengya , Adler Paul R , Larsen Ashley E , Suh Sangwon
Published: October 2020

Pesticide usage in the U.S. has more than doubled since 1960, raising concerns on its human and ecological health implications. The literature indicates that pesticide application rates for the same crop vary widely across geographies, while the magnitude of variation and its underlying drivers are poorly understood. Here, we present a new dataset on farm-level pesticide application for maize in the U.S. Using the dataset, we derived four human and ecological health impact metrics, (1) environmental impact quotient, (2) acute hazard quotient, (3) chronic hazard quotient, and (4) freshwater ecotoxicity, and analyzed their relationships with various climatic and biophysical factors including precipitation, growing degree days (GDD), soil conductivity, and irrigation practices. Our results show that the potential human and ecological health impact of pesticide use per unit maize harvested vary by 5–7 orders of magnitude across the 891 maize-producing counties in the U.S. All four best-fitted models are statistically significant, explaining 21% to 28% of the variations in the impact intensities across counties. Among the climatic and biophysical factors examined, GDD was the most significant variable for all four metrics. This suggests that climate change may adversely affect human and ecological health impact intensities of pesticide use for maize, which may increase 22%–471% by 2100 under the 2 °C warming scenario. Besides, electrical conductivity and the percentage of cropland irrigated were significant for multiple impacts. The large remaining variability unexplained by our analysis suggests that behavioral and management factors, which were not captured in our model, play a crucial role in pesticide use, calling for the interventions targeting them.
What do Bloch electrons in a magnetic field have to do with Apollonian packing of circles?
Authors: Satija Indubala I
Published: October 2020

Integral Apollonian packing, the packing of circles with integer curvatures, where every circle is tangent to three other mutually tangent circles, is shown to encode the fractal structure of the energy spectrum of two-dimensional Bloch electrons in a magnetic field, known as the ‘Hofstadter butterfly’. In this Apollonian–butterfly-connection, the integer curvatures of the circles contain in a convoluted form, the topological quantum numbers of the butterfly graph—the quanta of the Hall conductivity. Nesting properties of these two fractals are described in terms of the Apollonian group and the conformal transformations. In this mapping, Farey tree hierarchy plays the central role, revealing how the geometry and the number theory are intertwined in the quantum mechanics of Bloch electrons in a magnetic field.
The use of ash-mineral mixtures for the construction of high-strength coatings of forest roads
Authors: Chudinov S
Published: October 2020

Forest roads are characterized by difficult transport and operating conditions and a considerable distance from sources of traditional road-building materials. Local ash and slag waste of the state district power station is an effective road-building material for the construction of forest roads. The article presents the test results of the building properties of the ash of the Reftinskaya TPP and the physicomechanical characteristics of the ash-mineral mixtures prepared with its use. Based on the results of laboratory studies, technical solutions for the use of ash-mineral mixtures in the design and construction of high-strength coatings of forest roads have been developed: the main design indicators, requirements for the materials used in the composition, approximate compositions of the ash-mineral mixtures are given, technical measures for the organization and quality control of construction work are assigned.
Modeling of multiple forest use under different management scenarios
Authors: Chumachenko S , Kiseleva V , Kolycheva A , Mitrofanov E
Published: October 2020

The concept of multiple forest use envisages the implementation of several types of forest use considering ecological and social aspects. The question arises about the compatibility of harvesting timber, non-wood resources, and getting ecosystem services provided by forests. This question can by answered by means of computer modeling of forest dynamics at different patterns of silviculatural activities. The paper presents the ecologo-physiological simulation model FORRUS-S designed for the forecast and analysis of forest stand dynamics, including the logging-induced one, and complemented by special blocks for the computation of non-wood resources and recreational potential. The model was run for three scenarios: natural development, selective cutting, and intensive forest use, and applied to three objects in two natural zones of Russia. The scenario envisaging selective form of logging is the most convenient for multiple forest use. Intensive pattern of forest management is partially compatible with food resources and conflicts with the recreational potential of a territory. The model can be applied for both the research properties (finding correlations between stand characteristics and intensity of forest use) and the selection of optimal pattern of forest management for a concrete economic entity.
The diversity of dicotyledonous edible plants in Nam Dong Conservation Area, Thanh Hoa Province, northern Vietnam
Authors: Huu Nguyen Cuong , Averyanov L , Egorov A
Published: October 2020

The survey was completed in assistance with ethnic groups living in Nam Dong Conservation Area in June –August 2019. The study was focused on the dicotyledonous plants used in Nam Dong Conservation Area as a food plants. Observed and documented plants belong to 49 species and 33 families; among them 21 trees, 10 shrubs, 12 herbs, and 6 lianas. These species are used commonly as fresh or cooked vegetables. The investigation underlines the significance of available ethnobotanical knowledge pertaining to the use of the dicotyledonous wild edible plants for the human benefit.
The diversity of tree species in plant communities with the prevalence of the Dipterocarpaceae family tree species in Binh Chau –Phuoc Buu Nature Reserve - Vietnam
Authors: Danilov D A , Thi Duong Nguyen , Belyaeva N V
Published: October 2020

This work analyzes the biodiversity of evergreen rainforests in Binh Chau – Phuoc Buu Nature Reserve, Vietnam. 4 combinations of the dominant tree communities of the Dipterocarpaceae family were observed in the park: Dipterocarpus formation, Shorea formation, Anisoptera formation, and Vatica formation. The study found 104 species from 38 families (Dipterocarpus formation – 45 species, Shorea formation – 86 species, Anisoptera formation – 21 species, Vatica formation -26 species). The most common are woody plants from the Anacardiaceae family - 8 species, the plants from the Clusiaceae and Dipterocarpaceae family are on the second place - 6 species. In general, the four studied plant formations have a different number of various tree species in their composition. The study shows that under the dominance of Shorea roxburghii G. Don, the plant community has the greatest biodiversity of plant species, whereas the smallest number of plant species is observed in phytocoenoses dominated by Anisoptera costata Korth. Fluctuations in the values of biodiversity indices are caused by the heterogeneity of the growth areas and previous anthropogenic impact.
Post-fire restoration of tree species in various soil conditions after surface fires zone
Authors: Danilov D A , Anisimova I M , Belyaeva N V , Kazi I A
Published: October 2020

The study of forest regeneration in stands exposed to fire has both fundamental and applied relevance. The objects of the study were the exposed to surface fires forest plots of various soil and hydrological conditions in the north-east of the Leningrad Region in the landscape of the Tikhvin ridge of the north-eastern part of the Valdai Hills. To study the natural renewal of tree species, circular plots of 10 m2 were created along a transect traced over a diagonal of the area exposed to fire. Post-fire impact on soils with different particle size distribution causes the formation of stands with different shares of coniferous and broad-leaf species. After the exposure of tree communities to fire, regeneration processes can follow different directions in the formation of the future planting composition, and that depends on soil and hydrological conditions. Knowing the succession status of the post-fire plant community, further silvicultural measures can be planned for the management of stand composition.
Lodgepole pine of Yukon origin in the European North of Russia
Authors: Demidova N A , Durkina T M , Gogoleva LG , Paramonov A A
Published: October 2020

The article is devoted to the study of Lodgepole pine plantations of northern Canadian (Yukon) origin, created in 1988 in the Arkhangelsk region on three sites with different growing conditions using different methods of the soil preparation for planting. The main research objective was studying the growth, sustainability and productivity of Lodgepole pine of Yukon origin in the conditions of introduction. The objects of research were three experimental plots of Lodgepole pine, created in 1988 in the Arkhangelsk region with two-year-old seedlings from seeds of Yukon origin. The results of Lodgepole pine growth in height, diameter and trunk volume indicate that this pine responds well to improved soil cultivation conditions and, undoubtedly, to pre-plant soil preparation. Lodgepole pine is characterized by good growth and straightness in the myrtillosum forest type and special microclimatic conditions on the Solovetsky Islands. Resulting from the study of growth and development of Lodgepole pine of Yukon origin, it was concluded that the creation of fast-growing forest plantations of this species is recommended in productive forest types of the hylocomiosa group (oxalidosum and fresh myrtillosum).
Control of Sosnovsky’s hogweed (Heracleum sosnowskyi Manden.) in forests using herbicides
Authors: Egorov A , Pavlyuchenkova L , Bubnov A , Partolina A , Postnikov A
Published: October 2020

The article presents the results of field experiments carried out in the Leningrad Region in 2018 and 2019 with the aim to test the effectiveness of modern herbicides against Sosnowsky’s hogweed and other undesirable herbaceous plants in various types of forest lands: in a clear cutting, spruce plantation, hayfield and on the side of a forest road. The herbicides Magnum (water dispersed granules, 600 g/kg of metsulfuron-methyl), Ancor-85 (water dispersed granules, 750 g/kg of potassium salt of sulfometuron-methyl) and a mixture of Roundup (360 g/l of glyphosate acid) and Ancor-85 were found to be highly effective against Sosnowsky’s hogweed. Magnum stimulates the growth of grasses and is promising for use in areas not occupied by woody vegetation. Anchor-85 is proposed for the care of European spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) in the spring.