bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of radiation gonadal doses for the American–Ukrainian trio study of parental irradiation in Chornobyl cleanup workers and evacuees and germline mutations in their offspring
Authors: Chumak Vadim , Bakhanova Elena , Kryuchkov Victor , Golovanov Ivan , Chizhov Konstantin , Bazyka Dimitry , Gudzenko Natalia , Trotsuk Natalia , Mabuchi Kiyohiko , Hatch Maureen , Cahoon Elizabeth K , Little Mark P , Kukhta Tatiana , Berrington de Gonzalez Amy , Chanock Stephen J , Drozdovitch Vladimir
Published: March 2021

Radiation doses of parents exposed from the Chornobyl accident as cleanup workers or evacuees were estimated in the National Cancer Institute-National Research Center for Radiation Medicine trio (i.e. father, mother, offspring) study aimed at investigating the radiation effects on germline de novo mutations in children as well as other outcomes. Paternal (testes) and maternal (ovaries) gonadal doses were calculated along with associated uncertainty distributions for the following exposure pathways: (a) external irradiation during the cleanup mission, (b) external irradiation during residence in Pripyat, and (c) external irradiation and (d) ingestion of radiocesium isotopes, such as 134Cs and 137Cs, during residence in settlements other than Pripyat. Gonadal doses were reconstructed for 298 trios for the periods from the time of the accident on 26 April 1986 to two time points before the child’s date of birth (DOB): 51 (DOB-51) and 38 (DOB-38) weeks. The two doses, DOB-51 and DOB-38 were equal (within 1 mGy) in most instances, except for 35 fathers where the conception of the child occurred within 3 months of exposure or during exposure. The arithmetic mean of gonadal DOB-38 doses was 227 mGy (median: 11 mGy, range 0–4080 mGy) and 8.5 mGy (median: 1.0 mGy, range 0–550 mGy) for fathers and mothers, respectively. Gonadal doses varied considerably depending on the exposure pathway, the highest gonadal DOB-38 doses being received during the cleanup mission (mean doses of 376 and 34 mGy, median of 144 and 7.4 mGy for fathers and mothers, respectively), followed by exposure during residence in Pripyat (7.7 and 13 mGy for mean, 7.2 and 6.2 mGy for median doses) and during residence in other settlements (2.0 and 2.1 mGy for mean, 0.91 and 0.81 mGy for median doses). Monte Carlo simulations were used to estimate the parental gonadal doses and associated uncertainties. The geometric standard deviations (GSDs) in the individual parental stochastic doses due to external irradiation during the cleanup mission varied from 1.2 to 4.7 (mean of 1.8), while during residence in Pripyat they varied from 1.4 to 2.8 (mean of 1.8), while the mean GSD in doses received during residence in settlements other than Pripyat was 1.3 and 1.4 for external irradiation and ingestion of radiocesium isotopes, respectively.
Rapid dynamical study of Newton’s law of heating with machine vision
Authors: Pili Unofre B
Published: March 2021

A movie of the moving temperature pointer of a dial-type thermometer was analysed in Tracker, a machine vision application, revealing a satisfactory match between the theory and the experimental data. Also presented is an empirical model for the time-dependent angular positions of the pointer.
Inflationary cosmology- A new approach using Non-linear electrodynamics
Authors: Sarkar Payel , Kumar Das Prasanta , Samanta Gauranga Charan
Published: March 2021

We explore a new kind of NLED field as a source of gravity, which can accelerate the Universe during the inflationary era. We propose a new type of NLED lagrangian which is characterised by two parameters: α (dimensionless parameter) and β (dimensionful parameter). We investigate the classical stability and the causality aspects of this model of inflationary expansion by demanding that the speed of the sound wave

c

s

2

>
0

and

0
≤

c

s

≤
1

. Corresponding to

0
≤

c

s

2

≤
1

, we find

0.382
(
1.828
)

≤
β

B

2

≤
0.288
(
1.469
)

for α = 0.1(1.0). The equation of state parameter ω = −1/3 requires

β

B

2

=
0.126
(
0.757
)

corresponding to

α
=
0.1
(
1.0
)

. We find that the Universe is accelerating i.e.

a

̈

>
0

(which results in the deceleration parameter q < 0 (i.e. ω > −1/3)), provided

β

B

2

≥
0.126
(
0.757
)

. During inflation, the energy density

ρ

B

is found to be maximum and is given by

ρ

B

max

=
0.65

/

β

. The magnetic field necessary to trigger the inflation is found to be

B
≃

0.4

ρ

B

max

0.65

=
4
×

10

51

Gauss

, where

ρ

B

max

(
∼

ρ

inf

)
=

10

64

GeV

4

is the energy density of the Universe during the inflationary expansion. Our model also predicts the e-fold number

N
=
71
(
64
)

that the magnetic field at the end of inflation is about B = 10−10 (10−4) Gauss corresponding to z = 0(1000) and this agrees quite well with the experimental prediction of the e-fold number. With α = 0.3(1.0) and

β

B

2

=
0.3974
(
0.8239
)

, we find the scalar spectral index n

s
 = 0.9649, consistent with the PLANCK 2018 CMB data. Further, with

α
=
0.3
(
1.0
)
,

β

B

2

=

0.3974
(
0.8239
)

, we predicts the tensor-to-scalar ratio r = 0.1417(0.1449) and the tensorial spectral index

n

T

=
−
0.0177
(
−
0.0181
)

.
Measuring parity violation in the Stochastic Gravitational Wave Background with the LISA-Taiji network
Authors: Orlando Giorgio , Pieroni Mauro , Ricciardone Angelo
Published: March 2021

Parity violation is a powerful observable to distinguish a
cosmological background of Gravitational Waves (GWs) from an
astrophysical one. Planar single GW interferometers, both on ground
and in space, are unable to measure the net circular polarization of
an isotropic Stochastic Gravitational Wave Background (SGWB). In
this paper, we explore the possibility of detecting circular
polarization of an isotropic SGWB by cross-correlating two
space-based detectors planned to be launched around 2034: LISA and
Taiji. We compute the response of such a network to chirality and we
perform a Fisher forecast analysis on the I and V Stokes
parameters for the SGWB. We find that a clear measurement of
chirality can be claimed for a maximally chiral flat signal with
amplitude h
2 ΩGW ≃ 10−12 at the frequency
scales of LISA and Taiji.
Tensor non-Gaussianity in chiral scalar-tensor theories of gravity
Authors: Bartolo Nicola , Caloni Luca , Orlando Giorgio , Ricciardone Angelo
Published: March 2021

Violation of parity symmetry in the gravitational sector, which manifests into unequal left and right circular polarization states of primordial gravitational waves, represents a way to test high-energy modifications to general relativity. In this paper we study inflation within recently proposed chiral scalar-tensor theories of gravity, that extend Chern-Simons gravity by including parity-violating operators containing first and second derivatives of the non-minimally coupled scalar (inflaton) field. Given the degeneracy between different parity-violating theories at the level of the power spectrum statistics, we make a detailed analysis of the parity violation on primordial tensor non-Gaussianity. We show, with an explicit computation, that no new contributions arise in the graviton bispectra if the couplings in the new operators are constant in a pure de Sitter phase. On the other hand, if the coupling functions are time-dependent during inflation, the tensor bispectra acquire non-vanishing contributions from the parity-breaking operators even in the exact de Sitter limit, with maximal signal in the squeezed and equilateral configurations. We also comment on the consistency relation of the three-point function of tensor modes in this class of models and discuss prospects of detecting parity-breaking signatures through Cosmic Microwave Background B-mode bispectra.
Gyrokinetic simulation of low-frequency Alfvénic modes in DIII-D tokamak
Authors: Choi G.J. , Liu P. , Wei X.S. , Nicolau J.H. , Dong G. , Zhang W.L. , Lin Z. , Heidbrink W.W. , Hahm T.S.
Published: March 2021

Global gyrokinetic simulations find that a beta-induced Alfvén eigenmode (BAE) and a low-frequency mode (LFM) co-exist in the DIII-D tokamak experiments. The simulated LFM mode structure and many of its parametric dependencies are consistent with experimental observations. The LFM can be excited without fast ions and has a frequency inside the gap of the beta-induced Alfvén-acoustic eigenmode (BAAE). However, an antenna scan shows that it is NOT the conventional BAAE. Instead, the LFM is an interchange-like electromagnetic mode excited by non-resonant drive of pressure gradients. Furthermore, the simulated BAE mode structure is consistent with the experiment but the frequency is lower than the experiment. The compressible magnetic perturbations significantly increase the growth rates of the BAE and LFM. On the other hand, trapped electrons and equilibrium current have modest effects on the BAE and LFM.
How irreversible are steady-state trajectories of a trapped active particle?
Authors: Dabelow Lennart , Bo Stefano , Eichhorn Ralf
Published: March 2021

The defining feature of active particles is that they constantly propel themselves by locally converting chemical energy into directed motion. This active self-propulsion prevents them from equilibrating with their thermal environment (e.g. an aqueous solution), thus keeping them permanently out of equilibrium. Nevertheless, the spatial dynamics of active particles might share certain equilibrium features, in particular in the steady state. We here focus on the time-reversal symmetry of individual spatial trajectories as a distinct equilibrium characteristic. We investigate to what extent the steady-state trajectories of a trapped active particle obey or break this time-reversal symmetry. Within the framework of active Ornstein–Uhlenbeck particles we find that the steady-state trajectories in a harmonic potential fulfill path-wise time-reversal symmetry exactly, while this symmetry is typically broken in anharmonic potentials.
Effectiveness Research-based Textbook of In vitro Rooting of Sipahutar Pineapple (Ananas comosus L.) on Undergraduate Biology Education Students’ Science Process Skills in Universitas Negeri Medan
Authors: Daulay Marta Ito , Harahap Fauziyah , Manurung dan Binari
Published: March 2021

The purpose of this study is to test the effectiveness of research-based textbook of In vitro rooting of Sipahutar Pineapple (Ananascomosus L.) in improving science process skills of undergraduate biology education students. This study is quasi-experimental research using pretest-posttest designs. The research subjects are determined through cluster random sampling method. Data collected through pretest and posttest and measured by using essay tests. The data statistically analyzed by using independent sample t-test using SPSS 22 for Windows. The result shows that there is a significant difference between experiment class and control class in science process skills (tcount=9,678; p=0,00). Further, N-Gain test performed to find out the increasing score from pretest to posttest. The result shows N-Gain score for group using Research-based Textbookof In vitro Rooting of Sipahutar Pineapple (Ananascomosus L.) is 0.64 (moderate category) while the other group N-Gain score is 0.35 (low category). It concluded that Research-based Textbook of In vitro Rooting of Sipahutar Pineapple was effective in improving students’ science process skills.
Preparation of SiO2/α-Fe2O3 Composite from Rice Husk and Iron Sand as a Photocatalyst for Degradation of Acid Black 1 Dye
Authors: Lubis S. , Mustafa I. , Ermanda Y. , Ramadhani M.
Published: March 2021

The SiO2/α-Fe2O3 composite was successfully synthesized using impregnation method by using rice husk ash as silica (SiO2) sources. Hematite (α-Fe2O3) was derived from iron sand which was extracted using hydrochloric acid and ammonium hydroxide as co-precipitation agent. The synthesized SiO2/α-Fe2O3 composite was characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and diffuse reflectance (DR) UV spectroscopy. The performance of as prepared SiO2/α-Fe2O3 composite was evaluated on photodegradation of acid black 1 (AB 1) dye under UV light irradiation. The results showed that SiO2/α-Fe2O3 composite exhibits high photocatalytic acitivity for degradation of acid black 1 with degradation efficiency up to 85.86% within 120 minutes. The photocatalytic activity of SiO2/α-Fe2O3 composite was higher than that of bare α-Fe2O3. The SiO2/α-Fe2O3composite also can remove textile wastewater containing AB1 dye up to 82.96%. This results suggest that SiO2/α-Fe2O3 composite holds a great potential for degradation of dyes and various application in wastewater treatment.
The Liverworts Bazzania (Lepidoziaceae) in Sicike-cike Natural Park, North Sumatra, Indonesia
Authors: Siregar E S , Pasaribu N , Rambe H Z R
Published: March 2021

Sicike-cike Natural Park is one of important forest region inhabited by numerous species of bryophytes, including Bazzania. Bazzania species constituted the largest member of the family Lepidoziaceae. Studies on the species diversity ofthe liverworts Bazzania in thisregionwas still limited and never conducted before. Therefore, the aim of this study was to explore the species diversity of Bazzania in Sicike-cike Natural Park, North Sumatra through specimen collection and exploratory survey in the forest area. Identification of the species was confirmed through microscopical examination on specimens by following the existing literatures. Based on our study, there are total of 13 species of Bazzania. The most common species was Bazzaniaerosa, while the less commonly found were B. calcarata, B. longicaulis, B. paradoxaand B. pectinata.This result is the first report of Bazzania in Sicike-cike Natural Park.
Variation in Growth of Centella asiatica of Samosir – Indonesia Accession with Phosphorus Fertilizer Cultivated at Samosir Field
Authors: Vinolina N S , Sigalingging R
Published: March 2021

Indonesia has a variety of biological natural resources. One of the plants that thrive is pegagan (Centella asiatica). This study aims to investigate the response of pegagan to phosphorus fertilizer on growth components and phytochemical content. This plant is very useful because of the bioactive content contained in these plants. This research was conducted using a single factor with six levels of P2O5 fertilizer dosage with a non-factorial randomized block design repeated 3 times. The levels of fertilizer dosage are 0, 20, 40, 60, 80, 100 kg P2O5/ha. The application of phosphorus had no significant effects on growth component; length of petiole, total leaf area, number of stolons and biomass production of Centella asiatica in acid soil conditions. The doses of phosphorus given to Centella asiatica plants reaches 40 kg P2O5/ha (F2) in which the fertilized plants tend to offer higher results than those with no fertilizers. Centella asiatica can still grow well even though the land conditions are very acidic. The phytochemical screening of leaves and roots of Centella asiatica was studied and showed positive tests for saponin, tannin, phenolic, flavonoid, triterpenoid, steroid and glycoside and negative for alkaloid.
The Effect of Red Dragon Fruit on Tumor Necrosis Factor-α (TNF- α) Tiggered by Sub-maximal Exercise
Authors: Harahap N S , Simatupang N , Suprayitno
Published: March 2021

Sub-maximal exercise also induces changes in the exercise of pro-inflammatory cytokine cell components such as TNF-α (Tumor Necrosis Factor-α).The purpose of this study was to determine the effect of red dragon fruit administration on changes in pro-inflammatory cytokines Tumor Necrosis Factor-α (TNF-α) after sub-maximal exercise. The research was carried out at the Faculty of Sport Science, State University of Medan. This study used experimental pretest and posttest group design. The research sample was twenty students divided into two groups. Group A: given sub-maximal exercise and placebo; Group B: received sub-maximal exercise and red dragon fruit. Sub-maximal exercise is conducted running on a treadmill with a sub-maximal intensity, a frequency of three times a week, lasting four weeks. The TNF-a examination was initially carried out at the end of the treatment and then evaluated in the laboratory using the ELISA method. The results showed a significant decrease in TNF-α levels after exercise in the sub-maximal exercise group given red dragon fruit compared to the sub-maximal exercise group given a placebo. The statistical results of the unpaired t-test showed that there was a significant effect of red dragon fruit on decreasing TNF-α levels after sub-maximal exercise. The conclusion is that red dragon fruit significant effect on decreasing TNF-α levels triggered by sub-maximal exercise in students.
Self-Determination and Technological Pedagogical Content Knowledge (TPACK): How Novice Teachers in Mathematics Education Surviving and Thriving in Disruption Era
Authors: Lestari Puji , Siregar Nurfadilah , Sujaya Krisna , Mulyani Dila Aulia , Syarifudin Muhammad Taufiq
Published: March 2021

The learning process has changed drastically from the face-to-face or classroom method to the one with technology utilization. One of the goals of mathematics education at school is to help students become smart citizens, namely, who can make decisions based on their needs, not others’ encouragement. Within the literature of motivation, there is a theory known as self-determination. The teachers’ efforts to develop students’ self-determination are reflected in those teachers’ capabilities in three ways: mastery of content, pedagogy, and technology, known as the TPACK. Mastery of both self-determination and TPACK is highly essential. This article discusses the instruments measuring both of them. In this study, we first arranged statements that correspond to both abilities’ indicators. Subsequently, we tested the legibility and performed the face validity and content validity by the experts. The methodology used in this study is a quantitative approach. Data were descriptively and quantitatively analyzed with the help of IBM SPSS software version 21. The results indicate that several statements need to be revised. However, the instruments have met both face validity and content validity. This result is also supported by the evidence of a high-reliability value and validity score. The instruments in this study, therefore, can be developed in further research.
Antioxidant Potential of Virgin Coconut Oil Reduced Creatine Kinase Levels in Non-Athlete Students receiving Submaximal Physical Exercise
Authors: Sinaga RN , Sinaga FA , Elvana A , Manalu N
Published: March 2021

Damage to the muscle cell acute and chronic can be caused by strenuous physical exercise. Oxidative stress that occurs during strenuous exercise contributes to muscle cell damage. One indicator of muscle cell damage is creatine kinase in the blood serum. Natural antioxidant can be given to counteract the free radicals and reduce oxidative stress. Virgin coconut oil is a natural plant that has potential as an antioxidant. The purpose of this study was to determine the effect of virgin coconut oil on muscle damage by looking at the creatine kinase activity during submaximal exercise in non-athlete students. This is an experimental study with a randomized control group pretest-posttest design. The sample in this study were ten people who were divided into two groups. The control group was given a placebo while the experimental group was given virgin coconut oil at a dose of 15 ml. All groups received submaximal physical exercise with an intensity of 80-90%, a frequency of 3 times a week for one month. Creatine kinase was measured before and after treatment. The creatine kinase activity in the control group increased significantly while the experimental group decreased insignificantly. Virgin coconut oil in this study significantly reduced creatine kinase activity. The antioxidant potential of virgin coconut oil can repair muscle damage in non-athlete students receiving submaximal physical exercise.
Synthesis and Characterization of Activated Carbon from Oil Palm Empty Bunches
Authors: Jasmidi  , Sari S A , Selly R , Rahmah S , Nasution H I , Zubir M , Banjarnahor L R , Efendi Y D
Published: March 2021

In this study, activated carbon was prepared from empty oil palm bunches obtained from Padang Bulan, Medan, North Sumatra. The empty oil palm bunches are cleaned, then mashed to obtain a particle size of 200 mesh which is then referred to as the oil palm empty bunches bio-sorbent. This bio-sorbent is then washed with water to remove impurities that may come from fertilizers or insecticides during processing in oil palm plantations such as K, Ca, Mg, Si and P, which are visible from the EDX analysis results of bio-sorbent before washed. From the EDX data after washing, the was observed if there are no peaks of these impurity elements. From the XRD pattern it can also be seen that there are some peaks missing after washing if compared to XRD bio-sorbents. Activated carbon then prepared by heating the bio-sorbent at 500 °C for 1 minute, and the XRD results show an amorphous structure as a characteristic of the formation of activated carbon. SEM images can also be observed that the difference in the surface of the activated carbon is smoother than the surface of the bio-sorbent, besides the activated carbon looks more homogeneous.
Students’ Interest in Concept-Based Learning and Drill Method Learning and Their Concept Mastery Achievement in Biology Instructional Methodology Course
Authors: Muttaqiin Arief , Lufri Lufri , Yogica Relsas , Fitri Rahmadhani
Published: March 2021

This research is part of the research on the development of the concept-based learning model and drill method. In this article, we will describe the relationship between students ‘interest in concept-based learning model and drill method with students’ mastery of concepts in the Biology Instructional Methodology course. A total of 37 samples were students majoring in Biology Education, Padang State University. Data were collected using instruments in the form of psychological questionnaires about student interests and instruments in the form of descriptive questions. Based on the analysed data, it is known that the variable student interest in the concept-based learning model and drill method has a positive relationship with student mastery of concepts, which is r= 0.169 and sig. 0.316 using the Spearman’s Rank Correlation Test. This shows that the higher the student’s interest in learning using the concept-based learning model and drill method, the higher the students’ mastery of concepts in the Biology Instructional Method course.
Experimental 1H and 13C Solid-State NMR Signal Assignment of Paramagnetic Copper (II) 2-Pyrazine-Carboxylate Complex using Density Functional Theory Calculations
Authors: Patil Bhargava Hanumanta , Peraje Pampa , Naik Dinesh , Rajaramakrishna R , Dittmer Jens , Kumara Swamy Shashi Kumar
Published: March 2021

We have acquired 1H and 13C solid-state NMR (ssNMR) spectra of the paramagnetic Cu(II)-2-pyrazine-carboxylate (Cu-Py) complex and assigned paramagnetic 1H/13C signals using density functional theory (DFT) calculations. The unpaired electron in Cu(II) ionexacerbates the 1H and 13C chemical shifts in the Cu-Py complex through hyperfine interactions, making the conventional NMR signal assignment non-feasible. Further, the nuclear fast relaxation in paramagnetic metal-organic system hampers application of routine ssNMR techniques for signal acquisition. In our work we have employed simple DEPTH experiment at 50 kHz magic angle spinning (MAS) for acquiring 1H and 13C 1D ssNMR spectra of the paramagnetic Cu(II)-2-pyrazine-carboxylate (Cu-Py) complex. The paramagnetic augmented (diamagnetic chemical shift + paramagnetic shift) 1D 1H and 13C ssNMR signals (shifts) from Cu-Py complex have major contribution from Fermi contact interaction due to proximity of the organic arm to Cu2+ ion (Cu2+-C/H atoms 0-5 Å). The unpaired electron spin density distributed over the pyrazine-carboxylate organic arm is crucial in understanding Fermi contact shifts and hence accounts for 1H and 13C ssNMR signal assignment. The theoretical Fermi contact shifts together with diamagnetic shifts, calculated using density functional theory (DFT) at B3LYP level with basis sets viz. 6-311G, 6-311G+(D) and 6-311G++(D), were compared with the experimental shifts to facilitate the process of signal assignment. Vibrational analysis of Cu-Py complex was performed at B3LYP level of theory with various basis sets in comparison with experimental IR data. This further assisted in double validation of DFT optimized Cu-Py structure used here for extracting Fermi contact shifts. Furthermore molecular orbital analysis on the DFT optimized Cu-Py structure articulates the spin density distribution mechanism, thereby stipulating the location of the unpaired electron in the Cu(II) dx
2
-y
2 orbital in Paramagnetic Cu-Py complex.
Student Perceptions of Augmented Reality (AR) Media in Calculus Courses
Authors: Elfitra  , Mansyur A , Taufik M.I
Published: March 2021

Learning media plays an important role in the learning process. The development of technology and science also has an impact on the development of learning media. One of the learning media developments that are currently still new is learning media using Augmented Reality. Augmented Reality is an application that combines the real world with the virtual world in two-dimensional or three-dimensional form which is projected in the real environment at the same time. This research is a descriptive study conducted by using a questionnaire to students. The descriptive analysis in this study examines students’ perceptions of Augmented Reality media in Calculus Learning. Augmented Reality media response in terms of aspects of Media Design, Material Content and Benefits. The results obtained by an average Augmented Reality media design is 85.7 with a decent category, the average Augmented Reality Media Material Content is 83 with a decent category and the average aspect of benefits is 83.5 with a decent category. Based on the rearata, the score for the observation aspect of AR learning media is 84.07 with a decent category. However, many improvements are needed, including a reduction in application capacity and 3-dimensional display.
Affective Assessment Tools Development in Biology Subjects for X Grade in State High School
Authors: Pratama D J , Edi S , Syarifuddin
Published: March 2021

This study aims to develop affective assessment tools in high school grade X Biology subject. The instrument developed will be tested for validity, reliability and practicality. The research was conducted at SMAN 1 and SMAN 2 Tanjungbalai. The development of affective domain assessment instruments is carried out using the 4-D model which is carried out in stages. The stage consists of Define, Design, Development and Dissemination. The result of research consisted of valid, practical and reliable affective assessment instruments that can be used to conduct affective assessments in schools. Validation value of the affective domain assessment instrument is 90.5%, categorized as good and worthy of use.
The Development of Science Student Worksheet for Elementary Student Grade IV Based on Scientific
Authors: Lubis S J , Harahap F , Saragi D
Published: March 2021

The research is a type of research and development that aims to determine the validity and response of students and teachers to the science student worksheet constructed on the science approach. Science student worksheet development applies the 4-D model development procedure consist of 4 stages specifically: define, design, develop, and disseminate. The subjects of this research were IVA& IVB class at SD IT Deli Insani consist of 55 students. The data collection instruments were in the formula of assessment sheets for material authorities, learning design authorities, layout, linguists, and the response questionnaire sheets for students and teachers. This development research produces the material, learning design, layout, and language with an average percentage level 93,5% which is characterized as legitimate and suitable for usage, and get a decent response from the students reached 96,2% and with decent criteria and response teacher getting 94,9% with decent criteria. Based on expert validation, the developed student worksheets are declared suitable for use by students, especially class four. Based on the responses of students and teachers, the students’ worksheets developed received a good response so that it was stated that the worksheets were easy to understand and interesting to learn. The benefits of developing science student worksheets based on the developed scientific approach are expected to be reference materials for educators in developing student worksheets according to the needs of students and in accordance with the demands of the 2013 curriculum.
Stability Analysis of the Corona Virus (Covid-19) Dynamics SEIR Model in Indonesia
Authors: Sinaga L P , Nasution H , Kartika D
Published: March 2021

Covid-19 is a type of virus that infects the respiratory tract or is also known as severe acute respiratory syndrome Corona virus-2 (SARS-CoV-2). Researchers through this study were trying to build a mathematical model of the spread of the Covid-19 virus and analyzed the stability of its critical points. This virus dynamic model was built based on the interaction between the suspect group with the exposed group and the interaction with the infected group. The virus spread model in this study consists of two critical points, namely a disease-free critical point and a disease endemic critical point. The two critical points will be stable if they meet the requirements for certain parameter values. Numerical simulations of virus dynamics in Indonesia were carried out using data on the number of susceptible people, the number under monitoring, the number of the infected, the number of cures and the number of deaths due to the virus. These data were obtained from the Ministry of Health of the Republic of Indonesia. Based on the data obtained, it was found that the simulation model of stability reached a critical point in a very long time. Therefore, treatment or vaccines are needed as a step to reduce the dynamics of Covid-19.
The Effect of Teams Games Tournament (TGT) Method on Outcomes Learning and Conceptual Knowledge in Physics Science
Authors: Panggabean Jonny Haratua , Defi Siregar Masda Sri , Rajagukguk Juniastel
Published: March 2021

This study aims to determine the effect of the TGT (Teams Games Tournaments) cooperative learning model on students’ conceptual knowledge on momentum and impulse material in grade X 7th state Senior High School (SMA) in Medan City. The research type is a quasi-experiment with a two-group pretest-posttest design. The instrument used in this study was a test of students’ conceptual knowledge in the form of multiple choices and an assessment sheet to measure student skills and student activities. After the learning was given, the two classes carried out a post-test. The experimental class obtained an average value of 83.19 and for the control class, an average value of 64.58 was obtained. And student learning activities in the cooperative learning process type TGT (Teams Games Tournaments) in three meetings experienced an increase with an average value of 72.4 (active) meeting I, 77.22 (active) meeting II, 82, 4 (active). Based on the test results, it was found that the cooperative learning model type teams games tournament had a significant effect on students’ conceptual knowledge on momentum and impulse material in grade X 7th state SMA in Medan City.
The Effect of Spin Coating Speed on Structural and Optical Properties of ZnO and ZnO/Dye Thin Films Synthesized by Sol-Gel Spin Coating Method
Authors: Motlan  , Siregar Nurdin , Panggabean Jonny Haratua
Published: March 2021

The ZnO thin films were successfully synthesized using sol-gel spin coating method. The surface other ZnO thin film then were coated with natural dye. Materials used were zinc acetate dehydrate, isopropanol, Diethanolamine and purple heart flower consecutively as based materials, solution, stabilizer, and dye. The ZnO thin films were grown glass by dropping Sol-gel on a surface of FTO glass with spin coating speed variation of 2000, 3000, 4000, and 6000 rpm. The ZnO thin films then successively pre-heated and pot-heated at 250°C and 550°C for 5 hours and holding time of 30 minutes. The source of the dye is boat lily flower was cut into small pieces and put into beaker glass. The sample then crushed with mortar and then milling until it becomes soft. Further, the extract was obtained by immersing it in aquadest, acetate acid, and ethanol with maceration technique. The ZnO thin films then immersed in an extract of dye solution for 24 hours to obtain ZnO/dye thin film. The XRD analysis shows that ZnO thin film size of within 26.5 – 36.9 nm. The optical properties of the ZnO and ZnO/Dye thin films were characterized using UV-Vis spectrometer. The UV-Vis spectrometer results show that there are variations of the ZnO thin film transmission as a result of spin coating speed of the Sol-gel spin coating method. The transmission of ZnO/dye thin films is higher than ZnO thin film and the absorbance of ZnO is higher than ZnO/dye thin films. The band gaps of the ZnO and ZnO/dye thin film were consecutively ranged 3.27 – 3.34 eV and 3.02 – 3.21 eV.
Molecular Docking of Quinine Derivative as Inhibitor in Sars-Cov-2
Authors: Roza Destria , Selly Rini , Munsirwan Rudi , Fadhilah Gianna
Published: March 2021

The discovery of various of new medicinal compounds from various research clarifies the important role of computational studies as the initial basis for finding sources of medicinal raw materials both from natural and synthetic. SARS-coronavirus 2 (SARS-CoV-2) or COVID-19 is the virus which is responsible for the outbreak that affects almost the entire world began in early 2020. This study aim is to determine the interaction between SARS-CoV-2 and quinine derivative compounds by utilizing and developing quinine plants as medicinal ingredients, especially Corona antivirus. The research was conducted in silico with the molecular docking method. The docking software used in this research is AutodockVina. The results showed that from the 10 tested compounds against SARS-CoV-2 virus cells, all of ithas the ability as an antivirus with the binding affinity of around -6 kcal / mol. The native ligands have the best binding affinity among the tested compounds which is around -7.9 kcal / mol. This is also supported by the number of hydrogen bondings and bond lengths as well.
Enhancing Students Multivariable Calculus Learning Through Online Formative Feedback
Authors: Mukhtar  , Mulyono  , Firdaus M
Published: March 2021

Feedback is a major component of formative assessment and thus can be said to have a high influence on student learning experiences. It is used to inform students of their strengths, weaknesses, and strategies so that the gap between their current knowledge and understanding and the desired standard of achievement can be narrowed. However, research shows that students are less encouraged to engage in the feedback process mainly because of their difficulty in relating to and reflecting on feedback comments. In this paper, we look at how to support the provision of formative feedback through e-learning tools. Our aim is to increase the acceptance of feedback and to reinforce the quality of feedback through the way the feedback is communicated to students. This study describes how communication activities promote deep learning.
Effect of the Vaccine on the Dynamics of Speread of Tuberculosis SIR Models
Authors: Nasution Hamidah , Sitompul Pardomuan , Sinaga Lasker P
Published: March 2021

Tuberculosis (TB) is an infectious disease that is very dangerous and can cause death and Tuberculosis (TB) is an infectious disease that causes the most deaths or is called the world’s biggest killer among infectious diseases, claiming more than 4000 lives every day. The unprecedented Corona Virus pandemic has a serious impact on people with pre-existing health conditions such as Tuberculosis. Tuberculosis is not caused by heredity and Tuberculosis is curable. Treatment of TB disease is time-consuming and costly. Therefore the term prevention is better than cure very precisely for Tuberculosis. One of the efforts made by the government is to provide vaccines. This study uses the SIR (susceptible, infected, and recovered) model by considering the effect of vaccines. Also, this study adopts the application of the Optimum Control theory which aims to provide control over the parameters that affect the spread of Tuberculosis. The purpose of this study is not only to show the dynamics of the spread of tuberculosis but also to see to what extent the effect of vaccines reduces the spread of tuberculosis. And how does the optimal control theory influence the spread of tuberculosis?This research is proposed to estimate the basic reproduction number (R0) from the dynamics of the Tuberculosis epidemic. The basic reproductive number ((R0) is often used as a threshold parameter to determine the boundary betweenextinction and endemic. If R0<1 indicates the dengue virus will become extinct and if R0> 1 shows the Tuberculosis is endemic. By considering vaccines identified a slowing of the spread of tuberculosis.
Worksheet to Built Critical Thinking Skills for Prevalence Covid-19 in Indonesia on Limited Time: Curve Matching Modelling
Authors: Bunawan Wawan , Sabani  , Lubis Rajo Hasim
Published: March 2021

Data on the spread of covid 19 in Indonesia is usually displayed in the form of a bar chart and a graph of the function of the number of people versus time for cases of increase, death and recovery. Display data in the form of graphs and diagrams is quite adequate for use in television news shows or breaking news. The Covid 19 case can be used as a source of authentic learning data in the Data Processing Workshop course investigation. Curve matching based data modelling can be developed in the form of scientific worksheets. The challenge of developing worksheets is at what stages must be done in order for the mathematical model to match the distribution of the data. The development of worksheets has met the academic requirements in terms of pedagogy and knowledge content. The validity and reliability of the worksheets have met the requirements according to the validator’s decision and evidence of empirical data analysis. Worksheets are developed based on excel, SPSS and Matlab with studies based on critical thinking skills. The scientific worksheets can improve critical thinking skills needed in the 21st century with several relevant indicators. The limitation of this study is that the prediction formula produced still does not meet the real data that occurs for cases of infection, recovery and death for a long time interval. The original research contained in the learning source data is authentic and continues to move during the pandemic. data is inputted into scientific worksheets that apply critical thinking skills in excel, spss and matlab presentation.
Best Medium for Production and the Activity of Biosurfactant from Local Strain of Pseudomonas
Authors: Priyani Nunuk , Munir Erman
Published: March 2021

A local strain of Pseudomonas has been isolated from Belawan, a big port in Medan, North Sumatera. This isolate was already tested on its ability to break down carbofuran, an active compound of widely used pesticide. The ability of bacteria to degrade carbofuran is closely related to the ability of bacteria to secrete biosurfactant. This compound promotes bacteria on carbofuran metabolism. This study aimed to find out the best medium for the local strain of Pseudomonas to produce biosurfactant and to characterize the compound. The isolate was cultured in several media with different combination of three different carbon sources which are glycerol, glucose, and olive oil; two types of nitrogen sources: sodium nitrate and ammonium sulfate at C/N ratio 20 and 60, two different time of incubation, 24 and 72 hours. The parameters observed were the bacterial growth, the concentration and the activities of biosurfactant. The results showed that during 24 hours of incubation the best medium for the production of biosurfactant was the combination of glucose and ammonium sulfate with C/N ratio was 60. The bacterial population was 2.230 at OD 621 nm, the highest biosurfactant activity, the Index of emulsion was 0.42 and the surface tension was 36.3 mN/m and the concentration of biosurfactant was 75.530 g/L. Meanwhile during 72 hours of incubation the best medium was shown by the combination of glucose and ammonium sulfate with C/N ratio was 20. The bacterial population was 2.252 at OD 621 nm, the Index of emulsion was 0.25 and surface tension was 30.0 mN/m and the biosurfactant concentration was 76.494 g/L.
Geothermal Fluid Identification at Geothermal Area Sorik Marapi using 2d Resistivity Imaging
Authors: Kadri Muhamad , Nordiana M.M.
Published: March 2021

This research is done to determine the geothermal fluid flows by using 2D resistivity imaging and to identify the stones that compile the mineral by using XRD at geothermal Area Sorik Marapi, North Sumatera Province. The area is located at 99°32’.050” E- 0°41’193’ N to 99°32.861” E- 0°41’214’N. The results from XRD by using difractometer Jeol-350 Shimadzu 6100 Show that the intensity from x ray difraction has the geothermal fluid spreads laterally to the geothermal manifestation. Four lines were surveyed by using 2d resistivity imaging for geothermal delineation purpose. The 2d resistivity imaging survey site shows the existence of geothermal fluid flows. The maximum depth of investigations for the surveys is 31,3 meters and 155 m of length of each line. The array used in this study areWennerSchlumberger. In general the results show that all the subsurface is made up of limestone (resistivity value of less 100 ohm-m) and clay with resistivity also less than 100 ohm-m in all the sections. XRD survey shows the mean mineral that compile the get othermal stones at Sorik Marapi are Quartz (O2Si) and magnesium (Mg). This mineral is the mean mineral that compile the clay.
Development of Test Instrument Based Realistic Mathematics Education to Improve High Order Thinking Skills
Authors: Fadlila N , Sagala P N
Published: March 2021

Based on result of PISA 2015 in mathematics showed that characteristics of learning mathematics Indonesia students still used to the Lower Order Thinking Skill. Based on it, developed test instrument becomes important. This Research aims to develop and produce a test instrument based on realistic mathematics education to improve the high order thinking skills for grade VIII students. The type of research is a development research (Research & Development), where this research using the ADDIE model. ADDIE consist five stages: Analysis, design, development, implementation and evaluation). This research was conducted in one of the junior high schools in Medan. The result showed that the quality of test instrument had been successfully developed from validity aspect, practicality aspect and effectiveness aspect.
Facial Emotion Detection Using Haar-Cascade Classifier and Convolutional Neural Networks
Authors: Riyantoko P A , Sugiarto  , Hindrayani K M
Published: March 2021

Computer vision has the challenge to detect the facial emotions of humans. Recently, in computer vision and machine learning, it’s possible to detect emotion from video or image accurate. In our research will propose to classify facial emotion using Haar-Cascade Classifier and Convolutional Neural Networks. The experiment uses the FER2013 dataset which was collected for the facial expression recognition dataset, and we proposed seven classified facial expression. The CNN model gain MSE and accuracy value based on epoch variety. The results showed that with the increase in the epoch value, the smaller MSE value would be obtained, likewise, the accuracy value would be increased. Thus, the proposed algorithm of CNN is proven to be effective for facial emotion detection.
Generation Reliability Enhancement based on Reliability Indices
Authors: Al-Bahrani L T , Saaed W , Al-Kaabi M
Published: March 2021

Reliability of generation system is an important aspect of planning, designing and operating for forecasting the plant capacity growth to make assurance that the totality generation is adequate to secure demand. The probability distributions correlating with the reliability indices may be utilized as complementary measures for accurate description and worthy information for system planners and operators. In the current research, the yearly load demand and its impact on the reliability of generating units was highlighted by some reliability indices that standardize against the international usefulness custom which are, Loss of Load Probability LOLP, Loss of Load Expectation LOLE, Loss of Energy Expectation LOEE, Loss of Energy Probability LOEP and Expected Energy Not Served EENS. This article is also dealing with the issue of generation capacity reserve assessment and the relation between the system reliability level and the expansion of the load. The notion of capacity extending analysis is clarify using a system of 4 stations. The effect on system reliability of adding a generation unit to the overall system can be observe in terms of decreasing the reliability indices and increasing the system Effective Load Carrying Capability (ELCC). This article has been used the Loss of Load Expectation LOLE in terms of day/ year as a critical limit for reliable and unreliable system.
Dengue prediction model: A systematic review using social network analysis
Authors: Wahyuni S N , Sediyono E , Sembiring I
Published: March 2021

Since 1968, Dengue Harmonic Fever’s incidence in Indonesia has continued to rise and has become a public health issue. Indonesia has the largest number of Dengue Harmonic Fever cases than 30 other epidemic countries worldwide. It is very important to carry out research related to dengue cases’ prediction to prevent the spread of Dengue. This literature review is intended to determine the extent of the dengue prediction approach carried out by previous researchers, and a research gap will be obtained. The algorithm used to cluster articles is a modularity algorithm, using several open-source tools to process data. The online databases used are Google Scholar and Crossref by using keywords: journal, algorithm, prediction, and Dengue. The data are taken from the expansion of 1928-2020. This study’s results are 200 articles that are suitable and divided into four clusters of important articles. Also, several important parameters were obtained in the prediction study of dengue fever, namely humidity, temperature, rainfall, and population density.
SIMO Converter Design as Emergency Power Supply Multi Output for Disaster Areas
Authors: Ferdiansyah I , Effendi M Z , Shamil M
Published: March 2021

This paper discusses the design of emergency power supply systems in disaster affected areas. Communication and information on post-disaster conditions is very important to be known by the family or authorities. However, a condition that often occurs after a disaster is that the communication system is cut off due to loss of electricity sources. The proposed system aims to provide backups of electrical energy especially in communication equipment such as cellphone chargers and Backup Battery systems on BTS. The flyback converter topology applied provides a multi output voltage of 5 volts for cellphone chargers and 13 volts for Battery systems on BTS, where each system is able to provide an SOC of 20-40%.