bluuebunny/crossref_metadata_2025 huggingface dataset:
Bühlmann credibility model with correlated risk parameters
Authors: Angelica  , Nurrohmah S , Fithriani I
Published: January 2021

Credibility theory is one of the tools to predict the amount of future claims by combining the experience of the claims in the past of a particular policyholder and external information, which is called manual rate, obtained from the experience of a large group of policyholders. One of the credibility theory that is widely used is Bühlmann credibility, which accommodates the heterogeneity of risk exposures, noted by unique risk parameters for each individual. However, Bühlmann credibility requires an assumption that the risk parameters are independent, which almost surely cannot be fulfilled by individuals living in the same area. Therefore, the Bühlmann credibility estimator with correlated risk parameters is formed by utilizing the orthogonal projection in Hilbert space. Also, the parameters included in the model are estimated. In addition, the standard Bühlmann credibility estimator and the Bühlmann credibility estimator assuming correlated risk parameters are compared to predict the amount of future claims based on data from a life insurance company. Comparing the root mean square error, the credibility estimator with correlated risk parameters is better in predicting the amount of future claim, meaning that the predicted amount of claim is closer to the original amount of claim. Also, as the correlation increases, the root mean square error becomes smaller. Moreover, the credibility estimator applied to the data that is partitioned based on the amount of past claims shows better performance than when applied to unpartitioned data.
Generalized exponential Marshall-Olkin distribution
Authors: Mohammad R , Lestari D , Devila S
Published: January 2021

The distribution of generalized exponential was invented by Rameshwar D. Gupta and Debasis Kundu in 2007. The distribution was the result of a generalized transformation of the exponential distribution. This paper explained the generalized exponential Marshall-Olkin distribution which is the result of the expansion of the generalized exponential distribution using the Marshall-Olkin method. The generalized exponential Marshall-Olkin distribution has a more flexible form than the previous distribution, especially in its hazard function which has various forms so that it can represent survival data better. The flexibility characteristic is due to the addition of new parameters to the generalized exponential Marshall-Olkin distribution. We explained some characteristics of the Marshall-Olkin generalized exponential distribution such as the probability density function (PDF), cumulative distribution function (CDF), survival function, hazard function, mean, and moments. Parameter estimation was conducted using the maximum likelihood method. In the application, it was shown data with generalized exponential Marshall-Olkin (GEMO) distribution. The GEMO distribution was modelled to the waiting time data until the damage to a lamp. The data was taken from Aarset data (1987). The results of modelling the waiting time data until the damage to a lamp on the distribution of GEMO and was compared to the distribution of alpha power Weibull. A comparison of models using Akaike information criteria (AIC) and Bayesian information criteria (BIC) shows that the distribution of GEMO is more suitable in modelling the lamp damage waiting time data than the distribution of alpha power Weibull.
Characterization of microalgae from lowlands in South Sumatera (Indonesia) as a potential source for biodiesel production
Authors: Jumiarni D , Anggraini N
Published: January 2021

Biodiesel production technology from microalgae is widely considered as a potential and efficient method. This research was conducted to characterize microalgal species isolated from some lowlands in South Sumatera and investigated their potential for biodiesel production. Five microalgal culture isolate were selected and identified as strains of Chlorella sp PKB, Chlorella sp PPP, Chlorella sp SB, Crucigenia quadrata PTA and Scenedesmus sudetica PTA. These isolates were determined the growth rates, biomass and total lipid content. Under similar environmental condition, dried weight biomass of isolate were 1,30; 0,88; 0,74; 0,5; 0,26 respectively. Total lipid content of isolates were 35,2; 28,5; 25,6; 17,8; 8,4 respectively. Chlorella sp PKB showed the highest lipid content comparison others, whereas Chlorella sp SB showed the highest dried biomassa. The results suggest that only Chlorella sp PKB can be a possible candidate species for biodiesel production.
Development of higher order thinking skills based problem solving questions on the nervous system concept
Authors: Zen D , Huzaifah S , Santoso L M , Dewi S P
Published: January 2021

Research on the development of higher order thinking skills (HOTS) questions based on problem solving on neural system material aims to produce valid and reliable HOTS questions. The development of higher order thinking skills questions refers to Anderson & Karthwohl and Polya frameworks. The questions that developed are a multiple choice problem with five alternative answers. The evaluation process includes self-assessment, expert review, one-to-one and small groups. Readability questions are tested at the one-to-one stage. The results of the small group stages are then analysed item items, namely item validity and item reliability. The validity of items is calculated based on expert review validation, while the reliability of the questions is calculated using Anates 4.0. The results of the research conducted showed that the questions developed were valid (86,1%) and reliable (0,35). The results of this study can be used as a reference for teachers to provide HOTS questions and familiarize students with solving problems with these characteristics.
Students’ achievement and teachers’ perception in the implementation of lesson study-based cooperative learning
Authors: Hasan R , Lukitasari M , Ernawati Y
Published: January 2021

Lesson study (LS) initially developed in Japan with over a century is a form of teacher inquiry in which teachers in small groups undertake collectively a cycle of “plan-do-see” activities to improve pedagogy and learning practice. LS has been practiced in many countries worldwide as well as developing countries in South East Asia region. This paper reported the implementation of LS on enhancement students’ activeness in classroom and concept comprehension in biological class as well as teacher’s perception in improving their quality as LS applied. We used cooperative learning model in three cycles of LS practice of this study. The results showed that students’ activeness during LS in cycle I was 1.9% of excellent, 46.3% of good, 50.6% of fair and 1.2% of poor. The students’ activeness was better in cycle II become 7.4% of excellent, 56.2% of good, 36,4% of fair and 0% of poor. In cycle III students’ activeness rise to 11.7% of excellent, 71.6% of good, 16.7% of fair and 0% of poor. Student’s comprehension on biological concept in this study was increased from 64.2 to 75.8 and 82.7 in cycle I, II and III of LS, respectively. Those results reflected that LS implementation improved students’ activeness on biology lesson and concept comprehension in biology. On the other hand, all teachers evolved in this study perceived that LS implementation can improve teachers’ professional quality and promote teacher’s professional development. They strongly agreed that LS be beneficial for them to become a better-quality biological teacher.
Realistic mathematic education of students worksheet (LKS) for reasoning ability of mathematical reflection of class XI High School number 1 Lubuklinggau
Authors: Yanto Y , Luthfiana M
Published: January 2021

This research aims to develop high quality PMR based on Student Worksheet (LKS) to facilitate mathematical reasoning ability of grade XI students of SMA Negeri 1 Lubuklinggau. This research used research and development method (Research and development) and the stage of Analysis Design, Development, Implementation, and Evaluation. In the development stage, there are two kinds of processes, namely the development of LKS and LKS validation, then evaluated LKS by the experts of linguists, and media experts. Validity of LKS was developed categorized “Valid” with an average score of 3.09 was determined based on the LKS assessment result by 3 experts (material experts, linguists, and media experts) maximum score was 4.00. Data analysis used LKS Practicality analysis developed “Praktis” with an average score of 3.38 is determined based on the result of student response to LKS. Descriptive and statistical analysis. The effectiveness can be seen from the results of students achievement tests. Based on the results of the Test Achievement shows that the percentage mastery learning class XI SMA Negeri 1 Lubuklinggau was 87%. Thus, learning mastery reaches good criteria, In shortly, LKS that used in teaching and learning was effective.
Improving student learning activities in microbiology through lesson study activities
Authors: Irwandi I , Hasan R
Published: January 2021

Lesson study is an educator development program through collaborative and continuous learning based on the principles of collegiality. Lesson study can be implemented at various levels of education from primary schools to universities. The 4 cycles-lesson study presented here is aimed to improve students’ learning activities in microbiology subject in the Biology Education Department, Universitas Muhammadiyah Bengkulu. Students who engaged in this activity as much as 28 students. The lesson study activities were conducted in three stages: plan (plan), implementation (do) and reflection (see). Selected topics in this activity were infection and viruses. In addition to those topics, a practical class for (1) preparation of microorganism culture media and its sterilization; and (2) the proliferation of fungi and bacteria was also accomplished. The results showed that there is an improvement in the students learning activity by conducting a lesson study program on a microbiology course. The obtained results prove that lesson study can improve lecturer professionalism. This improvement in lecturer professionalism then will have an impact on the effectiveness of learning activities and on improving the quality of education overall.
The significance of Maillard reaction for species-specific detection gelatine in food industry
Authors: Ismarti I , Triyana K , Fadzillah N A , Nordin N F H
Published: January 2021

Many ingredients derived from animal have been distributed widely in foods, pharmaceutical, and cosmetic formulations which may invites issues due to religious restrictions. Thus, the species-specific detection has become an important issue among Muslims, Jews, Hindus, Vegan, and vegetarian communities. Some methods such as spectroscopy, chromatography, and DNA based method have been applied for this purpose. However, these methods use sophisticated technology, therefore need high skill and cost for industrial practice. Research needs to encourage the development of simple and portable instrument. This paper highlights the potency of the Maillard reaction for species-specific detection of animal derivatives in food, especially for gelatine. Gelatine from different sources revealed different amino acids composition. It will produce various sensory of active compounds such as colour, odour, and taste when subjected to Maillard reaction, depends on reactant substances and conditions of reaction. The differences will be the key principle in species-specific detection of the sources of gelatine.
The effect of civet coffee isolate and time fermentation on Robusta coffee protein profiles
Authors: Uliyandari M , Sumpono S , Muslim C
Published: January 2021

This research aims is to determine the effect of the isolate’s concentration of civet coffee and fermentation time on the protein concentration profile and protein molecular weight profile of Robusta coffee which fermented in vitro, in vivo, and without fermentation. Isolates of civet coffee made from microbial civet feces and made in five variants concentrations (2,91x108 CFU/mL; 2,91x107CFU/mL; 2,91x 106CFU/mL, 2,91x105 CFU/mL; 2,91x104 CFU/mL). In the fermentation process coffee Robusta beans marinated with various concentrations of coarse isolates. The coffee beans are fermented analysed by Uv-Vis spectrophotometer and the results obtained in vitro protein concentration of the lowest 50,95 μg/mL (fermentation time of 60 hours and isolates concentration of 2,91 x 108 mg/mL), coffee fermentation in vivo (167, 44 μg/mL), and coffee without fermentation (217,61 μg/mL). The protein molecular weight profile is determined based on the results of electrophoresis. The higher the concentration of isolates civet coffee in the fermentation process, the more protein bands appear, and vice versa.
New candidate for traditional anti-malarial medicine from Kebiul seed (Caesalpinia bonduc) as a substitute for chloroquine in preclinical testing of mice
Authors: Sundaryono A , Ekolistiono A , Astuti A P , Muryani T S , Febrianti L , Nurleli N , Nurhamidah N
Published: January 2021

Kebiul seeds (Caesalpinia bonduc) are seeds from the Kebiul plant that are widely used by the community of Bengkulu in southern, Indonesia, especially by the Sarawai tribe as a cure for malaria. The purpose of this study was to scientifically prove the efficacy of Kebiul seeds as an anti-malaria medicine through preclinical testing in mice by measuring percent (%) chemosuppresion of crude extract of Kebiul seeds. Twenty-five mice were divided into 5 groups, K-, K +, P1, P2 and P3, each was infected with Palsmodium berghei. Three days after infection, the number of parasitemia of mice was calculated. When the number of parasites had reached 20-30%, mice were treated orally for 3 days according to their group. Group (K-) was treated with olive oil, group (K +) with chloroquine, and group P1, P2 and P3 with crude extract of Kebiul seeds at a dose of 0.028 g / kgbw, 0.056 g / kgbw and 0.084g / kgbw. The average number of parasitaemia developments was calculated from the 1st day of treatment to the 7th day through thin blood smears drawn from the tail. Calculation of the percentage (%) of chemosuppression was done by comparing the mean number of parasitaemia in the negative control (K-) and one in the treated group. As the result, the average percentage (%) of chemosuppresion in the administration of crude extract Kebiul seeds at a dose of 0.028 g / kgbw was 51.21% higher than the administration of chloroquine (50.77%). Moreover, it has been reported in several areas including Bengkulu that malaria is resistant to chloroquine. Therefore, based on this result, Kebiul seed extract at a dose of 0.028 g / kgbw can be developed as a new traditional medicine as a substitute for anti-malaria medicine chloroquine.
Betweenness centrality in corona product of Path and Star graphs
Authors: Haryadi T I , Susilowati L
Published: January 2021

Betweenness centrality is a concept in graph theory which is currently widely used in network analysis. The network can be a computer network, a criminal network, social interaction network, etc. The concept of betweenness centrality studies the potential ability of a point to exert influence on a network. If there is a point
x
in the shortest path between two points, then point
x
has the potential to influence information passing through that path. This paper will investigate the concept of betweenness centrality in the corona operation between path and star graph. Corona operation is one of the operations on graph theory that works between two graphs. The corona operation will duplicate the second graph and connect each copy to the first graph.
The comparison of the ordinal logistic model with the classical regression model
Authors: Yensy N A
Published: January 2021

This research’s aims was to provide an alternative for statistical user who were interested in analysing the functional relationship between ordinal response and explanatory variable. The data used was the data of Students on Generation 2017 JPMIPA FKIP Bengkulu University. The test statistic from the modified probability ratio in ordinal logistic had a higher test power than the F test in the classical linear regression. Overall the probability of rejection of ordinal logistic tended to be lower than the classical regression. At condition of p close to one, the test power of the ordinal logistic would be the same as the classical regression. Ordinal logistic model tended to be more selective in choosing variables that significantly affect the response, resulting in a simpler model than the classical regression. The results of the research with the classical linear model obtained variables that influence the student GPA were UN score, High School Report, UNIB admission pathway, High School Status and interaction of UN Score and High School Status. While the ordinal logistic model produced influential independent variables were the UN Score, High School Report, High School Status and the interaction of UN Score and High School Status.
Practicality test of student worksheet (SWS) based on: Action, Process, Object, Schema (APOS model) assisted on Geogebra the subject of Riemann sum
Authors: Hanifah H
Published: January 2021

The APOS Model is a Mathematical Learning Model Based on Theory: Action, Process, Object, and Schema (APOS). The APOS Model is a refinement of the Calculus Learning Model Based on APOS Theory. The APOS Model has syntax with phases: Orientation, Practicum, Small Group Discussion, Class Discussion, Exercise or Evaluation. Development of SWS based on APOS Model assisted on Geogebra in the subject of Riemann Sum developed using Plomp design which consists of three stages: 1) preliminary research, 2) prototyping phase, and 3) assessment phase. The purpose of this research was to find out how practicality of SWS was being developed, and how the criteria of practicing SWS based on the APOS Model assisted by Geogebra in the Riemann Sum discussion topic. The instrument used to collect data was the SWS practicality instrument in the form of a Likert scale. Research subjects were: one-to-one test conducted by a lecturer, a teacher, 3 senior students. Small group test by 3 groups of senior students with 3 students in each group. Large group test by 30 students in class B on the 3rd semester of Program Studi Pendidikan Matematika Universitas Bengkulu. After processing the data, the average score of practicality test of SWS was: one to one trial = 82.5%; according to the small group test = 77.63%; according to the large group test = 79.0%. The average value of practicality of SWS by users was 79.71 and belongs to the practical category.
The enhancement of mathematical reasoning and problem solving ability through metaphorical thinking approach
Authors: Purwasi L A , Fitriyana N
Published: January 2021

The objective of this study was to determine the effect of metaphorical thinking learning approach on mathematical reasoning and problem solving ability. This research used quasi-experimental method. The population of this study was the third-semester students of mathematics education study program at STKIP PGRI Lubuklinggau. The sample selection was done by using saturated samples. Based on the analysis of the t-test, the results of the study showed that 1) tobtained (2.351) of the ability of mathematical reasoningwas more thanthe ttable(2.06), so H0was rejected and Hawas accepted.It can be concluded that there was significant influence of the metaphorical thinking learning approach on the students’mathematical reasoning ability; and 2) tobtained(2.311) of the problem solving skill was more than the ttable(2.06), so H0was rejected and Hawas accepted. It can be concluded that there was a significant effect of the metaphorical thinking approach on the students’problem solving skill. In short, metaphorical thinking approach has influenced the students’ mathematical reasoning and problem solving ability significantly.
The effectivity of corrective formative evaluation on ability to understand geometric concepts
Authors: Zamzaili Z , Swita B
Published: January 2021

The aim of this study are to know the effectiveness of the corrective formative evaluation on the ability to understand geometric concepts of the students. This research is a quasi-experimental study with sample thirty two students. The data was analysed by using covariance analysis with students’ initial ability as covariate. The results of the study show corrective formative evaluation give effective contribution on the ability to understand geometric concepts with a contribution 44.5%. This study also indicates there is a significant effect of students’ initial ability as covariate on the ability to understand geometric concepts 35.2%. The average the ability to understand geometric concepts of the students taught with corrective formative evaluations is higher than conventional classes.
Improvement of student mathematics learning outcome on polyhedra topic by applying generative learning model in the class
Authors: Dianti A , Yensy N A , Rusdi R
Published: January 2021

Aiming of this research was to improve student learning outcome in mathematics Grade VIII SMP Negeri 11 Kota Bengkulu by applying Generative learning model in the class management. The design of this research was classroom action research with the steps were: planning, acting, observing and reflecting. The subject of this research was 32 students of Grade VIII B SMP Negeri 11 Kota Bengkulu on even semester academic year 2018/2019. Data collection was done by using step 4 application in student worksheet and cycle test sheet. The generative model steps in this research were step 1 preparation, step 2 focusing, step 3 challenge and step 4 application. Class management with applying generative learning model improved student learning outcome by: (1) step 1 preparation trained student to remember the topic; (2) step 2 focusing trained student to construct the concept by them self; (3) step 3 challenge trained student to solve the real problem using concept that they got; and (4) step 4 application trained student with the exercises. The average of student learning outcome improved from first cycle to third cycle were: 66,48; 74,70; 83,75 with classical learning outcomes were: 43,75%; 62,50%; 87,50%.
The correlation between learning interest and mathematics achievement in grade VII SMP PGRI Bengkulu
Authors: Karlina T , Saltifa P , Sari R K
Published: January 2021

This correlational study aims to determine the effect of learning interest forwards in mathematics achievement in Junior High School students PGRI Kota Bengkulu. The sampling in this study used a purposive sampling technique with consist12 student, grade VII, which is 5 boys and 7 girls. The data is collected by using a questionnaire and documentation. Then, the data is analysed using correlation analysis. Based on the results of the analysis, it is concluded that students’ interest in learning has a positive effect on mathematics achievement.
Improving conceptual understanding through inquiry learning by using a jigsaw method in abstract algebra subject
Authors: Sari W P , Haji S
Published: January 2021

This study was aimed at improving conceptual understanding through inquiry learning by using a jigsaw method. This cyclical classroom action research was conducted in four phases including planning, implementation, observation, and reflection. Thirty-seven bachelor degree students of semester 6 (even semester, academic year 2018-1019) of Mathematics Education, Faculty of Education and Teacher Training, University of Bengkulu were used as subjects of this study. Results showed that inquiry learning by using a jigsaw method improved students’ conceptual understanding. Average scores the students gained increased from 61.89 in cycle I to 78.37 in cycle II.
The exploration of the elementary geometry concepts based on Tabot culture in Bengkulu
Authors: Agusdianita N , Widada W , Afriani N H , Herawati H , Herawaty D , Nugroho K U Z
Published: January 2021

Geometry’s direct objects were abstract. It was a learning material that was difficult for elementary students. Therefore, learning was needed close to the minds and daily lives of students. One of them was “Tabot” Culture. That was the ethnomatematics approach. The purpose of this research was to explore elementary geometry concepts based on Tabot Culture. We apply an explorative-qualitative approach. The subjects of this study were the makers of the Tabot, elementary students, and elementary mathematics teachers. This was a needs analysis. Activities were carried out through direct observation, documentation, in-depth interviews and focus group discussions. The research instruments were anecdotal direct observation sheets, and interview guides. Data were analysed qualitatively. The results of the study found that the culture of Tabot provides reinforcement of student character that was obeying the principle, thinking logically, critically, working hard, curiosity, independence, confidence. The geometrical concepts that exist in the Tabot culture were the cube, the beam, the pyramid, the prism, the sphere and its elements. Also, understanding of two-dimensional figure. We conclude that Bengkulu Tabot culture can be used as a starting-point for learning the achievement of geometrical concepts and strengthening student character.
Level of student understanding in solving geometry problems based on taxonomy of SOLO (Structure of Observed Learning Outcomes)
Authors: Agustinsa R , Muchlis E E , Maizora S
Published: January 2021

This research aimed to determine and classify the level of student understanding in solving geometry problems with taxonomy of SOLO (Structure of Observed Learning Outcomes). The material been examined was the geometry of planes and spaces. This research was a type of qualitative research conducted by the method of think loud. The research results were: 55% of students had an understanding that was at a multistructural level with indicators that have been able to use some concepts that was correct but not yet right in terms of linking concepts and 39% of students have been able to use a correct concept (unistructural level). Then about 5% of students have an understanding at the relational level that have been able to use some correct concepts and connect them, whereas 1% of students have a level of prestructural understanding. Based on the research results, it can be concluded that levels of student understanding in solving geometry problems are various from pre-structural level until relational level.
The development of test instruments to support students’ ability on mathematical learning evaluation course
Authors: Susanta A , Susanto E
Published: January 2021

The purpose of this study was to develop mathematics test instruments for secondary school students that is valid, reliable, a good discrimination, and a good level of difficulty. This research was a research and development using the stages of instrument development, namely: (1) compiling test instrument specifications, (2) writing test instruments, (3) examining test instruments, (4) conducting test, (5) analyzing items, (6) fixing the test. The instruments used in this study consisted of expert validation sheets with index Aiken analyze and student response sheets. The subject in this study was thirty secondary students of the Mathematics Education Study Program, Faculty of Education, University of Bengkulu who took mathematical learning evaluation course. The results of the research showed that in developing of the instruments obtained were 160 items of multiple choice test for seventh and eighth grade. The results of the analysis showed that all test instruments were reliable with a high category, good discrimination, and easy to medium difficulty level. The results of student responses in preparing test instruments showed high criteria with an average score 49.70.
Inculcation of the values of character education in the process of learning mathematics in grade VII SMP 10 Bengkulu City
Authors: Anggraeni N A , Komalasari R
Published: January 2021

This study is intended to solve the problem of how to instill the values of character education in the background with the rise of people who begin to do dishonorable acts, such as the law to moral degredation, and therefore the need for the integration of the values of character education. These problems were discussed through a field study conducted at SMP 10 Bengkulu City. Research data obtained by free interviews and observations. All data were analyzed using a phenomenological approach and descriptive analysis using induction logic, deduction and reflection. The results showed that the values of character education contained in grade VII mathematics materials included the values of religious character, good personality, social care, honesty and hard work. The way the teacher instills the values of these characters is by getting used to reading prayers before and after learning, encouraging learning and giving questions with a level of difficulty that gives challenges to students.
Design speed bump piezoelectric used pressure method (case study Jambi University gate portal)
Authors: Pathoni H , Pratiwi D , Fuady S , Noval M
Published: January 2021

Speed bump was a device for producing mechanical energy from a motor run through it. Piezoelectric was a device for producing electrical voltage that sourced from the energy pressed the piezoelectric. This research used speed bump as a source of mechanical energy which pressed piezoelectric for producing voltage. The results showed that piezoelectric speed bumps producing varied voltages. The voltage resulted that varying the highest voltage generated around 1 - 1.8 volts. In the other research the resulting voltage was not so high. It depended on many factors finding in the field.
Developing mastery of electricity and magnetic concept for pre-service physics teacher
Authors: Hakim L , Hakim A , Sulistyowati R , Lefudin L
Published: January 2021

The mastery of concept of electricity and magnetic is ability to understand the concepts of electricity and magnetic both in theory and practice. The concept of electricity and magnetic is an important concept for students in dealing with real problems in daily life. The development of ICT in learning provides many opportunities for educators to integrate electricity and magnetic concepts in learning. The purpose research is to develop mastery of the concept electricity and magnetism pre-service physics teacher by using ICT. Utilization ICT in learning can helps students to understand abstract concepts and increase student interest in learning. The method used in this study is an experimental research design with pre-test-post-test control group design. The participants in this study were the students of physics education at a private university in the city of Palembang. The research sample is the students in 3rd semester of physics education programs. The sampling technique used is purposive sampling. The instrument used was a concept mastery test consisting of 45 multiple-choice questions. The results showed that the mastery of the concept of magnetic electricity for students who received ICT-based learning was significantly greater than the mastery of the concepts of students who got traditional learning.
The difference in the guided inquiry model towards critical thinking skills in physics subject at SMAN 3 Kota Bengkulu
Authors: Medriati R , Hamdani D , Harjilah N
Published: January 2021

This study aims to describe whether there are significant differences in students taught with guided inquiry models towards critical thinking skills in physics subjects. The research sample was students of class X MIPA 3 and X MIPA 4 in SMA Negeri 3 Kota Bengkulu even semester 2018/2019 on the concept of work and energy. This research is a study of quasi experiment with a design of non-equivalent control group design. For testing data used instruments of critical thinking skills, which are in the form of essays totalling six questions. The results of the descriptive analysis, the average score of critical thinking skills increased in the experimental class with guided inquiry models and control classes with the direct instruction model. The result of inferential analysis shows that guided inquiry learning has a significant effect on students critical thinking skills. So it can be concluded that there are significant differences in learning with guided inquiry models towards critical thinking skills in physics subjects’ students of SMA N 3 Bengkulu city.
Analysis of student responses toward ethnoscience based Direct Instruction learning model in learning physics applying Rasch Model Approach
Authors: Risdianto E , Dinissjah M J , Nirwana N , Sutarno M , Putri D H
Published: January 2021

The problem examined in this study was how students respond to learning with theDirect Instruction. Ethnoscience-based that connected the intensity and intensity of material with Bengkulu’s dol music in teaching and learning activities. The aim of the researchers was to analyze students’ responses to learning with the modelDirect Instructionbased on ethnoscience to find out whether the responses given by students were positive or negative. An analysis data using Rasch Model Approach. Student responses are said to be positive if students feel happy about the learning component used, the learning component used is new, students are interested in implementing the same learning in subsequent learning and students are interested in the learning components used. The results of the research obtained were 92% of students gave a positive response to learning with the modelDirect Instructionbased on ethnosains. In other words, students are happy with the components of learning that are applied.
The effect of inquiry-based science learning on students’ level of thinking
Authors: Damopolii I , Nusantari E , Kristianto D D , Nunaki J H , Kandowangko N Y
Published: January 2021

Student thinking in biology lessons has become the main focus of several recent studies. The research aims to reveal: (1) Differences in student level of thinking before and after the implementation of inquiry-based science learning; (2) Differences in student level of thinking before and after the application of conventional learning; and (3) differences in student level of thinking between students taught by inquiry-based science learning and conventional learning. Samples were 63 students in class X IPA SMA Negeri 2 Fakfak, West Papua. A total of 30 students in the experimental group, and 33 students in the control group. Data were collected using 9 items of students’ thinking ability test. To measure the thinking level of students, rubric 5 levels of SOLO Taxonomy are used. Data analysis were used Wilcoxon test and Mann Whitney Test. The results of the analysis show that 29 students experienced an increase and 1 student remained at the level of thinking in inquiry-based science learning class (p < .05), 14 students experienced an increase and 19 students remained at the level of thinking in the conventional learning class (p < .05), and students who taught inquiry science learning has a better level of thinking compared to students in conventional learning (p < .05). We conclude that inquiry-based science learning has a better effect on the level of thinking of students than conventional learning. Going forward, to improve students’ thinking skills, teachers can use inquiry-based science learning.
The effect of android-based earthquake game toward Bengkulu City elementary school student’s knowledge about earthquake disaster preparedness
Authors: Winarni E W , Purwandari E P , Wachidi W
Published: January 2021

Earthquake is one of the frequent natural disasters which is still unpredictable. Nevertheless, we can always be able to reduce and prevent its negative impacts by implementing earthquake disaster preparedness. This study aimed to examine the effect of an android-based earthquake game on Bengkulu City elementary school student’s knowledge about earthquake disaster preparedness. The subjects were fifth-grade elementary school students in Bengkulu City. The quasi-experiment research was conducted using Matching – Only Pre-test Post-test Control Group Design. Android-based earthquake game software used as a treatment in the experiment group. Data were collected using a multiple-choice test sheet instrument. The result found that the experiment group means knowledge about earthquake disaster preparedness was higher than the control group. It concluded that there was a significant difference between experiment group and control group. The advantages and limitations of the android-based earthquake game and its implication to earthquake disaster preparedness education discussed
Analysis antifungal compounds produced by endophytic bacteria from oil plant using Bioautography
Authors: Candrawati E , Rupaedah B , Sumpono S , Sundaryono A
Published: January 2021

This study was undertaken to evaluate the antifungal activities of the bioactive compounds poduced by endophytic bacteria isolated from oil palm plant using TLC-Bioautography. Antifungal compounds used in this study have been extracted from potential endophytic bacteria of previous studies using ethyl acetate solvent. The antifungal compounds was tested for its activity against the pathogenic fungus Fusarium oxysporum f.sp. by using TLC-Bioautography method. The results showed that there are 3 spots on the TLC plate for samples of B11 antifungal compound with an incubation time of 54 hours and B11 with an incubation time of 24 hours. Observation of bioautographic antifungal activity test showed the presence of inhibition zones with the largest average percentage given by B11 with an incubation time of 24 hours is 11.59%. The inhibition zone provided B11 with an incubation time of 54 hours is only 11.08%.
Analysis of the natural electric field at different sea depths
Authors: Yu P. , Zhang J.W. , Cheng J.F. , Jiang R.X.
Published: January 2021

The natural electric field at the depth of 0 ∼ 1500 m in high seas of South China Sea is obtained by using a new type of measuring device. The electric field data in the 0.01 ∼ 0.5 Hz and 0.5 ∼ 30 Hz frequency range are analyzed respectively. The results show that the induced electric field generated by the surface wave (about 0.14 Hz in the experiment) is obvious at the depth of 50 m but can be ignored at the depth greater than 100 m. When the depth increases from 50 m to 1500 m, the peak-to-peak value of the natural electric field gradually decreases. At the depth of 1000 m, the peak-to-peak values are 0.04 ∼ 0.08 μV/m in the 0.01 ∼ 0.5 Hz range, and 0.07 ∼ 0.1 μV/m in the 0.5 ∼ 30 Hz range. At last, the natural electric field in coastal water near Sanya City, where the water depth is 15 m, is measured by means of a sinking device. The results show that the peak-to-peak values are about 2 ∼ 4 μV/m in the 0.01 ∼ 0.5 Hz range and 2 μV/m in the 0.5 ∼ 30 Hz range. By comparing the natural electric field in high seas with that of coastal water, we find the latter has a larger peak-to-peak value at nearly the same water depth. In addition, line spectrum noise often occurs in coastal water, while it is rarely observed in high seas when the water depth is more than 50 m.
Does carbon pricing reduce emissions? A review of ex-post analyses
Authors: Green Jessica F
Published: January 2021

Carbon pricing has been hailed as an essential component of any sensible climate policy. Internalize the externalities, the logic goes, and polluters will change their behavior. The theory is elegant, but has carbon pricing worked in practice? Despite a voluminous literature on the topic, there are surprisingly few works that conduct an ex-post analysis, examining how carbon pricing has actually performed. This paper provides a meta-review of ex-post quantitative evaluations of carbon pricing policies around the world since 1990. Four findings stand out. First, though carbon pricing has dominated many political discussions of climate change, only 37 studies assess the actual effects of the policy on emissions reductions, and the vast majority of these are focused on Europe. Second, the majority of studies suggest that the aggregate reductions from carbon pricing on emissions are limited—generally between 0% and 2% per year. However, there is considerable variation across sectors. Third, in general, carbon taxes perform better than emissions trading schemes (ETSs). Finally, studies of the EU-ETS, the oldest ETS, indicate limited average annual reductions—ranging from 0% to 1.5% per annum. For comparison, the IPCC states that emissions must fall by 45% below 2010 levels by 2030 in order to limit warming to 1.5 °C—the goal set by the Paris Agreement (Intergovernmental Panel on Climate Change 2018). Overall, the evidence indicates that carbon pricing has a limited impact on emissions.
Risk and vulnerability of Mongolian grasslands under climate change
Authors: Nandintsetseg Banzragch , Boldgiv Bazartseren , Chang Jinfeng , Ciais Philippe , Davaanyam Enkhbaatar , Batbold Altangerel , Bat-Oyun Tserenpurev , Stenseth Nils Chr.
Published: January 2021

Climate change is projected to increase the aridity of semi-arid ecosystems, including Mongolian grasslands (MG), which provide ecosystem services that support food supply and pastoralist lifestyle. Here, we conducted a grid-scale (0.5° × 0.5°) probabilistic risk assessment of MG under climate change for 40 years (1976–2015) based on probability theory. We evaluated changes of risk (impacts) and vulnerability of MG to drought between the recent two decades R20 = 1996–2015 and the previous two decades P20 = 1976–1995. The risk is quantified as the product of the probability of hazardous drought and ecosystem vulnerability. The probability of hazardous drought is defined from the Standardized Precipitation–Evapotranspiration Index. Vulnerability is defined as the expected differences of key ecosystem variables between years with and without hazardous conditions. The ecosystem variables are productivity (peak aboveground biomass, net primary productivity, and leaf area index) and root-zone plant-available soil moisture, simulated with a process-based vegetation model Organizing Carbon and Hydrology in Dynamic Ecosystems-Grassland Management validated with field observations of biomass and soil moisture. Results reveal that MG experienced more frequent hazardous droughts with rapid warming and slight drying during R20 aggravated by ever-increasing grazing intensity (34% compared to P20), which resulted in a reduction in soil water availability and grassland productivity, particularly in northeastern areas (20%–65%). The risk of drought to productivity increased by 10% between P20 and R20 over extended areas, particularly in northcentral and northeast Mongolia. The increase in the risk to MG was mainly caused by climate change-induced increase in the probability of hazardous drought and, to a lesser extent, by the increasing vulnerability. Recent droughts modify the risk to grasslands, particularly in northcentral and northeast Mongolia, suggesting that these regions need strategic management for both adaptation and ecosystem conservation to cope with climate change impacts.
Application of geodata for operational study of population placement and movement
Authors: Vorobyev A N
Published: January 2021

The aim of this article is to develop a methodology for compiling population density and mobility maps based on the data (geographic data) obtained from mobile operators in Irkutsk. Before its development, Russian and world experience in compiling maps based on mobile phones data was analysed. To achieve the aim, the author uses the data received from mobile operators (CDR), with which it was possible to identify information about the location of the device at any time. Based on the geographical location of base stations, one can analyse the density of users at a particular time and place. Based on the results of spatial data analysis, we obtained the signal density at a particular time. The results obtained now clearly demonstrate that geographic data from user devices and geographic information systems represent a very effective symbiosis of technologies, which serves for solving geographical problems. Such studies assess the general mobility of population for a particular region. Data on the location of a mobile phone can reveal the spatiotemporal distribution of urban residents at macro-and meso-levels in administrative districts of the city.
Investments in fixed capital and the prospects for sustainable development of the eastern border regions of Russia
Authors: Faleychik L M , Faleychik A A
Published: January 2021

The article is devoted to the analysis of the economic effects generated by the investments in the economy of the eastern border regions of Russia: the subjects of the Far Eastern Federal District and the Baikal region. Interregional comparisons and contrasts of the economic development indicators for 2011-2018 are given in comparable prices with 2011 as the base year. We discuss the factors hindering the accelerated growth of the economies of these regions. Particular attention is paid to the structure of investments in fixed assets, their effectiveness and impact on the specifics of the socioeconomic development in individual regions. There are multidirectional tendencies in the socioeconomic development of the studied regions. An analysis of investment flows and indicators of socioeconomic development in the eastern regions of the Russian Federation reveals that the existing institutional environment does not yet ensure sustainable economic development in the east of Russia. The integration processes here are hampered by an excessively strong dependence on the federal centre and a focus on specific investors. Therefore, the eastern Russian regions are forced to build their economic policy, focusing on creating attractive conditions for large investors. The stability of economic growth can be ensured only through stable growth of the region population and improvement of the human capital quality. For the successful implementation of large-scale development plans for the east of Russia, it is necessary to stop the processes of depopulation of the territory and maintain optimal proportions between the economic and demographic reproduction.
Assessment of the soil cover in the Irkutsk Region by cadastral value
Authors: Sapozhnikov P M , Granina N I
Published: January 2021

The article defines the specific indicators of the soil cadastral value for the agroclimatic subzones of agricultural landscapes in the Irkutsk Region. We calculate the cost of the soils most common in the region, which are present in the scales of land classification and in the Unified State Register of Soil Resources of Russia. For the first time for the Irkutsk Region, we assess the quality of agricultural land rather by soil types, taking into account the area of a land plot, standard yield, and technological (standard) costs, than by soil differences. Soils in the land-assessment zones are represented according to the USSR soil classification system of 1977 and the international WRB system. Average values of the specific indicator of the cadastral cost of lands are within 0.1 RUB/m2 in typical sod podzolic soils (Albic Folic Luvisols (Cutanic, Different)); they reach 0.3 rubles/m2 in sod alluvial saturated layered soils (Mollic Fluvisols (Orthofluvic Amphifluvic)) and 3.1 rubles/km2 in leached chernozems (Umbric Calcic Luvic Phaeozems) as well as 3.3 rubles/m2 in meadow chernozems (Chernic Phaeozems (Endocalcic)) and in sod alluvial saturated soils (Mollic Fluvisols). Low indicators of the cadastral cost of agricultural land are due to low values of agroclimatic potential, low humus content in these soils and low thickness of humus horizon. We indicate the sensitivity of the method for calculating the cadastral cost of lands (2017) to different soils and geographical conditions.