bluuebunny/crossref_metadata_2025_split huggingface dataset:
Educational apps for a prospective mathematics teacher in probability course
Authors: Ariyanto L , Supandi S , Kusumaningsih W , Silviani M T 
Published: October 2020

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractRangelands 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractThe 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Problems of environmental and economic sustainability assessments of specially protected natural areas
Authors: Fokina N A , Yachmenev E F , Ivanova V A 
Published: October 2020

Abstract
We discuss the key factors affecting the environmental and economic sustainability of specially protected natural areas (SPNA). Those are: regulatory and legislative; managerial; economic; environmental; and scientific and educational factors. We carried out an analysis of the factors to establish the main prerequisites and problems of assessing the environmental and economic sustainability of protected areas. We established that the factors can have both positive and negative effects on the development of protected areas. The negative influence of the factors can result in various threats to environmental and economic sustainability. A system of indicators for assessing the environmental and economic sustainability of protected areas has been proposed, consisting of two blocks: economic and environmental. The economic component of sustainability is characterized by the following indicators: the importance of environmental services, cost-effectiveness of recreational services, and the level of recreational development of protected areas. The environmental component is characterized by the following indicators: the level of compliance with the norms of the recreational load, the level of compliance with the rules and norms of hunting (fishing), the level of threat of anthropogenic impact, and the level of negative impact of natural factors. Criteria for evaluating the relevant indicators have been proposed.