bluuebunny/crossref_metadata_2025 huggingface dataset:
How the circulation and axial velocity deficit in Batchelor vortices affect their disturbance growth?
Authors: Hiejima Toshihiko
Published: July 2020

In this study, inviscid linear stability theory is used to investigate the compressibility effects of Batchelor vortices. The growth rates are obtained from asymptotic analysis with large wavenumbers, and it is shown that the growth of disturbances is affected largely by both the Mach number and the axial velocity deficit. From the maximum growth rates for various base flow conditions, the growth properties of Batchelor vortices are summarized reasonably by using a convective Mach number based on two relative Mach numbers for three-dimensional disturbances. In addition, the ratio of the circulation and velocity deficit at the maximum growth rate is closely related to the growth rate as a function of the convective Mach number because the correlation between the ratio and the growth rate is high when the Mach number is less than unity. Therefore, the compressibility effects, which are expressed as the relation between the growth property and the convective Mach number, are estimated simply from only the base flows (circulation and velocity deficit) in Batchelor vortices.
Laboratory verification of the buoyancy dependence of the carrying flow in a Maxey–Riley theory for inertial ocean dynamics
Authors: Miron P. , Medina S. , Olascoaga M. J. , Beron-Vera F. J.
Published: July 2020

We present results from laboratory experiments conducted in an air–water stream flume facility that provide controlled observational support for the buoyancy dependence of the drag-induced carrying flow velocity in a recent Maxey–Riley theory for inertial particle motion in the ocean.
Morphological profiling of tubercle bacilli identifies drug pathways of action
Authors: Smith Trever C. , Pullen Krista M. , Olson Michaela C. , McNellis Morgan E. , Richardson Ian , Hu Sophia , Larkins-Ford Jonah , Wang Xin , Freundlich Joel S. , Ando D. Michael , Aldridge Bree B.
Published: July 2020

Significance

Tuberculosis is a leading cause of death in the world and requires treatment with an arduous multidrug regimen. Many new tuberculosis drugs are in development, and the drug development pipeline would benefit from more rapid methods to learn drug mechanism of action and off-target effects. Here we describe a high-throughput imaging method for rapidly classifying drugs into categories based on the primary and secondary mechanisms of cellular damage caused by different antibacterials called Morphological Evaluation and Understanding of Stress (MorphEUS). We anticipate that MorphEUS will assist in rapidly pinpointing pathway of action of antibacterials for tuberculosis and other bacterial infections.
Crystallographic evidence of Watson–Crick connectivity in the base pair of anionic adenine with thymine
Authors: Mishra Manish Kumar , Kelley Steven P. , Smetana Volodymyr , Dixon David A. , McNeill Ashley S. , Mudring Anja-Verena , Rogers Robin D.
Published: July 2020

Significance

All genetic information on Earth is encrypted in DNA and RNA with the nucleobases and their pairs being the main information units. There are strict established rules how nucleobases can interact between each other in the DNA. These rules can though be affected by external factors such as radiation causing formation of the deprotonated charged species. Although such species are extremely unstable and low in abundance, they may affect local connectivity and introduce wrong units in the DNA chain, so proper characterization of their interactions is of enhanced importance. Here we could obtain anionic nucleobases in stable form in the solid state, opening the possibility to study them crystallographically and develop theoretical models for real biological systems.
Collective preferences in Dutch revealed by a covered-box experiment
Authors: Koster Anna de , Spenader Jennifer , Hendriks Petra
Published: July 2020

Sentences with plural expressions are compatible with distributive and collective interpretations. Adults
generally prefer collective interpretations, whereas children do not. Dotlačil (2010)
argues that the adult collective preference arises via an implicature. Adults can reason about alternative utterances with the
distributive marker each, thereby ruling out distributive interpretations in favor of collective interpretations.
Experiment 1 used the covered-box paradigm to investigate whether adults and children make the comparisons predicted by Dotlačil’s
implicature account. Adults’ responses suggest that they made comparisons with internally generated alternatives, supporting the
implicature account. Moreover, children seem to do so from around 11 years old onwards, after they have learned the distributive
character of each. Experiment 2 excluded the possibility that our results in Experiment 1 were influenced by
participants’ exposure to both collective and distributive pictures, making the collective interpretation more salient. Both
experiments thus point towards an implicature underlying the adult collective preference.
Split auxiliary selection with affected subjects in Old Majorcan Catalan
Authors: Salvà i Puig Sebastià
Published: July 2020

We aim to shed light on the split auxiliary selection found in Old Majorcan Catalan, in constructions where, instead of haver (‘have’), esser (‘be’) is used as the auxiliary verb for compound tenses, although just with persons 1 & 2; not only with unaccusative verbs, but also with transitive and unergative verbs. We claim that, in fact, these constructions have affected or undergoer subjects, derived from a lower position: at least, [Spec, ProcessP]. Hence, this system for auxiliary selection is mixed: both person-driven and event-driven. The Majorcan data provide evidence in favour of Ramchand’s (2008; 2018) decomposition of the vP, and for a nanosyntactic lexicalization of the auxiliaries: haver lexicalizes a chunk such as [Aux, i*], while esser lexicalizes only [Aux], in case a Person[+participant] head intervenes.
Palenque (Colombia)
Authors: Schwegler Armin
Published: July 2020

This article examines the revitalization of African language survivals in the former maroon community of Palenque, Colombia. During much of the 20th century, lexical Africanisms in everyday Palenquero creole were scant. Ritual language (Lumbalú) and the speech of a few elderly Palenqueros still contained isolated Africanisms, but these had become archaic, nearing extinction.

Profound sociolinguistic changes in Palenque in the 1980-90s introduced sentiments of negritud (‘black awareness’) and appreciation for “all things African”, lexicalia included. Thus, younger Palenqueros – with the help of some Lengua teachers – developed lists of Afro-Palenquero archaisms, rescuing them from oblivion. Various mechanisms spread these lexicalia “africana” to the wider speech community, where they are embraced as an index of their maroon and Afro-Colombian identity.
Prevalence of Marijuana use among Trauma Patients before and after Legalization of Medical Marijuana: The Arizona Experience
Authors: Levine Michael , Jontz Ashley , Dabrowski Paul , Claudius Ilene A. , Kreisler Rachael , Yee Noa , LoVecchio Frank
Published: July 2020

Background

In recent years, marijuana has become legal for use in many states, for either medicinal or recreational purposes. Objective: The primary objective is to determine if legalization of medical marijuana is associated with an increased use among trauma patients.

Methods

Prospective observational study included three periods; (pre-legalization; period 1); legal to grow for medicinal purposes but no dispensaries open (period 2); and legal to purchase medicinal marijuana in a dispensary (period 3). The study included all adult trauma patients presenting to an urban level I trauma center in Phoenix, AZ. The prevalence of use (as defined by positive urine drug screen or self-reporting) in each time period was determined and compared using two sample tests of proportion. Confidence intervals for prevalence (self-reporting only) were compared with published age matched data from the same geographical region of the general population.

Results

The prevalence of marijuana use increased significantly from pre-legalization (period 1) to post legalization (periods 2 and 3), but there was no significant change between the two post legalization periods. After controlling for age and sex, the odds of being marijuana positive post-legalization vs. pre-legalization was 1.36, p = 0.006 95%CI [1.09–1.7]. Overall, the prevalence of marijuana among trauma patients was nearly four-fold higher than the population as a whole in the same geographic region. Patients who use marijuana are more likely to use cocaine or amphetamine (OR 2.31; 95% CI 1.86–2.89) or had an ethanol level above 80 mg/dL (OR 1.57; 95% CI 1.32–1.87).

Conclusion

The legalization of medicinal marijuana is associated with significantly increased prevalence among trauma patients. It appears that legalization, rather than the convenience of dispensaries, is associated with an increase in use.
A SO(1,3) gauge theory of quantum gravity: quantization and renormalizability proof
Authors: Wiesendanger C
Published: July 2020

A new SO(1,3) gauge field theory classically equivalent to general relativity in a limiting case is quantized and the gauge-fixed path integral representation of the quantum effective action (QEA) is derived. Both the gauge-fixed classical action and the QEA are shown to be invariant under nilpotent BRST variations of the gauge, matter, ghost, antighost and Nakanishi–Lautrup fields defining the theory and a Zinn-Justin equation constraining the QEA is derived. Dimensional analysis and the various linear constraints put on the QEA plus the ones from the non-linear Zinn-Justin equation are deployed to demonstrate full renormalizability such that all infinities appearing in a perturbative expansion of the QEA can be absorbed into the gauge-fixed classical action solely by field renormalizations and coupling redefinitions—providing the third step in consistently quantizing the SO(1,3) gauge field theory at hands, and with it potentially gravity.
Note on equatorial geodesics in circular spacetimes
Authors: Aelst K Van
Published: July 2020

General results on equatorial geodesics are exposed in the case of circular spacetimes featuring an equatorial reflection symmetry. The way the geodesic equation equivalently rewrites in terms of an effective potential is explicitly recalled for circular and non-circular equatorial geodesics. This provides a practical tool to discuss their stability. Statements are illustrated in Kerr spacetime.
Did Schrödinger have other options?
Authors: Grave de Peralta Luis
Published: July 2020

Wave mechanics triumphed when Schrödinger published his now famous equation and showed how to describe hydrogen-like atoms using it. However, while looking for the right equation, Schrödinger first explored, but did not publish, the equation that we today call the Klein–Gordon equation. An alternative possible choice is explored in this work. It is shown a quasi-relativistic wave equation which solutions match the Schrödinger’s results at electron energies much smaller than the energy associated to the electron’s mass, but include, at higher energies, the relativity energy’s correction calculated in traditional first order perturbation theory. A discussion is presented about several consequences that would follow from using this quasi-relativistic wave equation as a quantum mechanics foundational equation. It is also suggested the academic use of this equation for introducing the students to the implications of the special theory of relativity in introductory quantum mechanics courses.
A dedicated phantom design for positron emission mammography performance evaluation
Authors: Torres-Urzúa Luis Fernando , Alva-Sánchez Héctor , Martínez-Dávalos Arnulfo , García-Pérez Francisco Osvaldo , Peruyero-Rivas Rocío Marlene , Rodríguez-Villafuerte Mercedes
Published: July 2020

A standard protocol for performance evaluation of positron emission mammography (PEM) systems has not yet been established. In this work we propose a methodology based on the design of specific phantoms for this imaging modality with component dimensions in accordance with typical breast lesion sizes together with the adaptation of current international protocols designed for clinical and preclinical positron emission tomographs (PET) systems. This methodology was used to evaluate the performance of the Flex Solo II PEM scanner in terms of spatial resolution, uniformity and contrast lesion detectability, recovery coefficients and spill-over ratios. Positron range effects were studied with 18F and 68Ga, which have very different energy spectra. Our results indicate that in-plane spatial resolution of the system is around 3.0 mm and 4.4 mm for 18F and 68Ga, respectively. Lesion detectability tests with sphere diameters between 4 and 10 mm confirmed that the PEM system can resolve all the spheres (hot or cold). Percent contrast values for 18F lie between 6%–38% and 34%–51% for hot- and cold- spheres, respectively; the corresponding intervals for 68Ga are lower, 4%–25% and 32%–44%. Regarding uniformity quantification, the system shows percentage standard deviations within 4.9%–5.7%, while the percent background variability measurements ranged between 6.7% and 10.9% for both radionuclides. Recovery coefficients measured with hot rod diameters between 1.5 and 9 mm, have values between 0.2–1.05 and 0.17–0.69 for 18F and 68Ga, respectively. Spill-over ratios have large values (0.22 in average) for both radionuclides. Our results indicate that the phantoms and the methodology developed in this work can serve as the basis for establishing an image quality protocol for the systematic evaluation of PEM systems, with a potential extension for performance evaluation of dedicated breastPET scanners.
Results from the Alfvén Eigenmode Active Diagnostic during the 2019-2020 JET deuterium campaign
Authors: Tinguely R A , Puglia P G , Fil N , Dowson S , Porkolab M , Fasoli A , Testa D , Contributors JET
Published: July 2020

This paper presents results of extensive analysis of mode excitation observed during the operation of the Alfvén Eigenmode Active Diagnostic (AEAD) in the JET tokamak during the 2019-2020 deuterium campaign. Six of eight toroidally spaced antennas, each with independent power and phasing, were successful in actively exciting stable MHD modes in 479 plasmas. In total, magnetic resonances were detected with up to fourteen fast magnetic probes. In this work, we present the calculations of resonant frequencies f
0, damping rates γ < 0, and toroidal mode numbers n, spanning the parameter ranges f
0≈ 30–250 kHz, −γ ≈ 0–13 kHz, and

|
n
|
≤

30

. In general, good agreement is seen between the resonant and the calculated toroidal Alfvén Eigenmode frequencies, and between the toroidal mode numbers applied by the AEAD and estimated of the excited resonances. We note several trends in the database: the probability of resonance detection decreases with plasma current and external heating power; the normalized damping rate increases with edge safety factor but decreases with external heating. These results provide key information to prepare future experimental campaigns and to better understand the physics of excitation and damping of Alfvén Eigenmodes in the presence of alpha particles during the upcoming DT campaign, thereby extrapolating with confidence to future tokamaks.
Carbon-based printed strain sensor array for remote and automated structural health monitoring
Authors: Zymelka Daniel , Togashi Kazuyoshi , Kobayashi Takeshi
Published: July 2020

The development of new technologies that incorporate strain sensors for reliable collection of relevant information on the state of civil structures is gaining attention. In this study, an array of 25 printed strain sensors made of inexpensive carbon-based materials is demonstrated. The sensors were incorporated into a flexible substrate with a double-sided copper wiring system. The laboratory tests revealed that the sensors have a gauge factor of 3.27. Moreover, these are highly effective in compensating for temperature variations owing to the full Wheatstone bridge configuration. Two sensor arrays equipped with a wireless data acquisition system that provides automated and remote measurements were deployed on a highway bridge for a five-month-long field test. The collected results revealed the versatility of the printed sensors for various applications within the framework of structural health monitoring (SHM), including the detection and monitoring of defects as well as quantitative analysis of traffic. The sensors demonstrate long-term durability and therefore, the potential for practical application in SHM.
Decoding multiclass motor imagery EEG from the same upper limb by combining Riemannian geometry features and partial least squares regression
Authors: Chu Yaqi , Zhao Xingang , Zou Yijun , Xu Weiliang , Song Guoli , Han Jianda , Zhao Yiwen
Published: July 2020

Objective. Due to low spatial resolution and poor signal-to-noise ratio of electroencephalogram (EEG), high accuracy classifications still suffer from lots of obstacles in the context of motor imagery (MI)-based brain-machine interface (BMI) systems. Particularly, it is extremely challenging to decode multiclass MI EEG from the same upper limb. This research proposes a novel feature learning approach to address the classification problem of 6-class MI tasks, including imaginary elbow flexion/extension, wrist supination/pronation, and hand close/open within the unilateral upper limb. Approach. Instead of the traditional common spatial pattern (CSP) or filter-bank CSP (FBCSP) manner, the Riemannian geometry (RG) framework involving Riemannian distance and Riemannian mean was directly adopted to extract tangent space (TS) features from spatial covariance matrices of the MI EEG trials. Subsequently, to reduce the dimensionality of the TS features, the algorithm of partial least squares regression was applied to obtain more separable and compact feature representations. Main results. The performance of the learned RG feature representations was validated by a linear discriminative analysis and support vector machine classifier, with an average accuracy of 80.50% and 79.70% on EEG dataset collected from 12 participants, respectively. Significance. These results demonstrate that compared with CSP and FBCSP features, the proposed approach can significantly increase the decoding accuracy for multiclass MI tasks from the same upper limb. This approach is promising and could potentially be applied in the context of MI-based BMI control of a robotic arm or a neural prosthesis for motor disabled patients with highly impaired upper limb.
Geometric properties of SOCP problem constraints on ℝ2 and ℝ3
Authors: Caturiyati  , Lestari H P , Krisnawan K P
Published: July 2020

This paper discusses the geometric properties of the intersection of SOCP problem constraints in case R2 and R3. SOCP Problem is one developing problem of linear programming where cone equalities or inequalities are as the constraints. If in linear programming problem, we can only concern to the optimal solution of the problem. However, the results of the intersection in SOCP require more serious observation. It is because of the cone-shaped constraints needed more guarantee of the convexity. The geometric properties of the intersection of SOCP problem constraints are 1.) Convex spaces in R2 and R3, 2.) Finite region, infinite region, finite space, or infinite space, and 3.) A polygon in R2 and not a polyhedron in R3.
Detection of palm fruit maturity level in the grading process through image recognition and fuzzy inference system to improve quality and productivity of crude palm oil (CPO)
Authors: Syaifuddin A , Mualifah L N A , Hidayat L , Abadi A M
Published: July 2020

The agricultural sub-sector that has the potential to develop is the plantation sub-sector. The plantation sub-sector contributes around 3.57% in GDP. Plantation sub-sector commodities whose growth is very rapid are oil palm which is the basic ingredient in making palm oil (CPO). The world need for oil and vegetable fats which continues to increase, must be supported by an increase in palm oil production. Determination / grading of oil palm fruit that is still done manually is certainly not effective if done for the large-scale oil palm industry, so there needs to be innovation in the process of selecting / grading palm fruit to obtain the right maturity of palm fruit. This research uses research & development methods. In general, this research detects the maturity level of palm fruit from its outer color. Test the colour of the outer palm fruit based on image taking. Parameters were formed based on the matrix and used the image process that is obtained as input values on the fuzzy inference system. Hardware integration with a digital image processing computing system is done so that the resulting data can be directly processed and recognized in real time. The recognition system for oil palm fruit maturity can be done by: sample data fulfillment, pre-processing of sample images, extraction of image data using the GLCM method, determining extraction features using regression methods, dividing data into training data and test data, doing clustering, building fuzzy systems use training data, testing the accuracy of the system. Obtained accuracy for training data is 73.07% and testing data is 71.4%.
Improvement of solution using local search method by perturbation on VRPTW variants
Authors: Wahyuningsih S , Satyananda D
Published: July 2020

One application of graph theory is to optimize the distribution problem. This problem can be solved using Vehicle Routing Problem with Time Window (VRPTW) model and its variants such as VRPTW, CVRPTW dan OVRPTW. This article comprehends the improvement of the solution with the local search method using perturbation on those variants. There are three parts in the method: generating an initial solution, improvement using local search, and perturbation. The initial solution was generated using the sequential insertion algorithm, the local search process used inter-route and intra-route operators, and the perturbation using ejection chain and double swap. Result of experiments showed that perturbation using double swap gave a better solution than ejection chain. This caused by two-times movement in the double swap that could examine all optimal solution possibilities. An example of implementation the VRPTW variant on distribution optimization is given in this article.
Development of Geogebra-assisted student worksheet for transformational geometry learning
Authors: Lestari H P , Sugiyono  , Listyani E
Published: July 2020

This study aims to develop Student Worksheets assisted by Geogebra software to be used in Geometry Transformation lectures. This research is a development research to develop Geogebra assisted Student Worksheet for Transformational Geometry learning. This development research refers to the Jan van den Akker model, namely: 1) Preliminary investigation, 2) Theoretical embedding, 3) Empirical testing, and 4) Process and results of documentation, analysis and reflection. The instruments in this study are the Observation Sheet and Tests. The results of this study are a set of Student Worksheets that can be used in Transformational Geometry learning. The Student Worksheets contain several student activities using Geogebra software to improve student problem solving skills. In general, developed Student Worksheets are of good quality. The aspect of practicality of Student Worksheets meets very good criteria based on student responses, namely with a score of 3.33 from the maximum score 4. Judging from the aspect of effectiveness, Student Worksheets meet good criteria based on the results of student problem solving ability tests, which score is 2.34 from the score maximum 4. The constraints faced in developing and implementing Geogebra-assisted worksheet are that students are still not fluent using Geogebra software and are still having difficulty interpreting Geogebra’s appearance and output.
Bifurcation analysis of electrostatically actuated MEMS micro-beam
Authors: Krisnawan K P
Published: July 2020

The aim of this paper is to investigate the effects of micro-beam stiffness and length change to the dynamic of the system. The nonlinear vibrations model of microbeam is simplified by Galerkin method and then transformed into a dynamical system. Based on the emergence of zero eigen values and the increase in the number of equilibria, the equation is analysed using normalization and the bifurcation diagram is drawn. Hopf and Pitchfork bifurcation showed by the normalized equation. The change of both parameters, stiffness and length, exhibits a codimension 2 bifurcation, Pitchfork–Hopf bifurcation. And, when we make a roundtrip around the Pitchfork–Hopf point, we meet Pitchfork bifurcation twice, a Hopf bifurcation, and a heteroclinic cycle.
Comparison of PROMETHEE –TOPSIS method based on SAW and AHP weighting for school e-learning readiness evaluation
Authors: Andayani S , Sumarno HM B , Waryanto NH
Published: July 2020

As the demand for using e-learning rising for all subjects at schools in digital era, the successful implementation of e-learning is important to be well prepared. The successful is influenced by many factors, including the provision of technology infrastructure, Human Resources, organizational culture and leadership factors. For this reason it is necessary to evaluate the readiness of schools in implementing e-learning, which is known as e-learning readiness (ELR). Evaluation of school ELR is carried out to analyse the strengths, weaknesses and dominant factors in implementing e-learning in schools, so that it can be a reference in policy making by related parties. ELR evaluation is carried out using the PROMETHEE and TOPSIS methods based on the weighting of Simple Additive Weighting (SAW) and Analytical Hierarchy Process (AHP). The data used is the readiness for e-learning implementation on the specified criteria. There are eight criteria to measure e-learning readiness (ELR) of schools, namely Psychological readiness, Sociological readiness, Environmental readiness, Human resource readiness, Financial readiness, Technological skill (aptitude) readiness, Equipment readiness, Content readiness. The evaluation model using the PROMETHEE and TOPSIS methods will provide the results of a school’s e-learning readiness ranking, based on the weighting of criteria determined using SAW and AHP. In addition, these results are expected to reveal the weaknesses that need improvement, as well as the strengths that support the implementation of e-learning.
The properties of magnitude ranking function of trapezoidal fuzzy numbers
Authors: Karyati  , Wutsqa D U , Binatari N
Published: July 2020

There are many ranking function of a fuzzy number. Yager, Maleki, Adamo, centre of maxima, centre of gravity, and soon. This paper discusses about the ranking function for trapezoidal fuzzy number that is called magnitude method. We get some properties related to the arithmetic operation. The other result says that this magnitude method has ordered properties.
Loss distribution approach for company operational risk analysis
Authors: Fuadi M Z , Kusumawati R , Inayati S , Sahid
Published: July 2020

The measurement of potential operational losses as an assessment of capital adequacy is needed by the company. One value that can be used to measure the potential loss of a company is Value at Risk (VaR). This paper aims to measure VaR based on the loss distribution using the Bayesian method where the loss frequency is assumed to be Poisson distribution and the loss severity is assumed to be the distribution Lognormal. VaR with Monte Carlo (MC) and Fast Fourier Transformation (FFT) simulations are compute using the values of the parameter of distributions that have been obtained by using the Bayesian method. In this paper, a numerical example of VaR estimation of a bank company is demonstrated to find the estimate VaR from several sources i.e. internal fraud, external fraud, business practices, employment practices, process failure, system failure and damage to assets. The results showed that the estimate VaR value equal to $ 8.2336044 with Monte Carlo and and $8.522028 with FFT simulation at 99% confidence level. These means that the company has the opportunity to experience operational risk losses which exceeds $ 8.2336044 and $8.522028 in the coming year by 1%.
Forecasting the farmers’ terms of trade in Yogyakarta using transfer function model
Authors: Hidayat L , Wutsqa D U
Published: July 2020

The transfer function model is one of the forecasting models that predicts future values from a time series based on its past values and the other variables. In this paper, the transfer function model is utilized to forecast the farmers’ terms of trade in Yogyakarta province. The farmers’ term of trade (FTT) is one indicator of farmers’ welfare. The variables included in the model inputs are the inflation and exchange rate in Yogyakarta. The procedure for transfer function modeling is through two stages, those are building a single input transfer function model for each input based on the autoregressive integrated moving average model, and then building the transfer functions simultaneously for all variables. The result demonstrates that the transfer function can predict farmers’ terms of trade accurately with the mean absolute percentage error value of 0.841%.
Ordinal regression model for analyzing factors affecting obesity levels in middle-aged adults in Indonesia
Authors: Kusumaningrum E , Kismiantini  , Wustqa D U , Fauzan M
Published: July 2020

Obesity is one of the major issues in many countries, including in Indonesia. In this study, the obesity category based on body mass index (BMI) is categorized into four levels, namely non-obese with BMI below 30 kg/m2, obesity I with BMI 30 – 34.9 kg/m2, obesity II with BMI 35 – 39.9 kg/m2, and obesity III with BMI above 40 kg/m2. The objective of this study was to assess factors affecting Indonesian obesity levels using ordinal logistic proportional odds models for each gender aged 40-65 years based on the fifth Indonesian Family Life Survey (IFLS 5) data. In totals of 4,658 male participants and 4,772 female participants were included in the analyses. The prevalence of severe obesity was associated with age, education, working status, and waist-hip circumference ratio for both men and women. With addition that the frequency of eating affects the prevalence of severe obesity for women. Men and women who had smaller waist-hip circumference ratio occurred to have higher probability of non-obese.
The characteristics of mathematical material deepening test for the national examination of junior high school
Authors: Prasetya Y , Hartono
Published: July 2020

The Material Deepening Test (MDT) is a test to prepare students to face the National Examination in Indonesia. The MDT test results are used as an evaluation and consideration of teachers towards students’ readiness to face the National Examination. The MDT test developed based on blue print of the National Examination. This study aims to describe the characteristics of the MDT for National Examination of junior high school in mathematics subject in Sleman Regency of Indonesia. This study is an explorative descriptive using a quantitative approach. Data collected by documentation technique. The characteristics of MDT analyzed using the classical test theory. The results show that the test is valid with Aiken’s index of 0.87 and included in the high category of content validity. Reliability index of test is 0.70 in good category. There are 19 items have discriminant index in good category, 8 items in quite good category, and 11 items in not good category. There are 3 items have difficulty index in easy category, 20 items in moderate category, and 15 items in difficult category. The most difficult material items for students are lines and angles, where the indicator is determining the angle formed from the real problem.
The ability of prospective teachers to pose contextual word problem about fractions addition
Authors: Kadir K , Kodirun  , Cahyono E , Hadi A L , Sani A , Jafar
Published: July 2020

The low understanding of students on fractional topic has hampered the development of mathematics learning in Indonesia. This study was conducted to investigate in depth the ability of prospective teachers in developing the problem. Thirty four mathematics prospective teachers were asked to ask about contextual word problem whose solution could be obtained from counting

4
5

and

2
3

. Data consists of a verbal protocol together with written notes made by the subjects. Qualitative analysis of the obtained data is focused on identifying the resulting problem structure and the type of context commonly used. The results showed that the most widely used contexts in the proposed story problem were the distribution of the cake, the weight of the object, the lots of the object, and the length of measurement. The structure of contextual problem produced by mathematicis prospective teacher has weaknesses in two components, namely: 1) in proposing appropriate contexts; and 2) in providing sufficient information so that the solution of the proposed problem can be obtained by applying the arithmetic concept of

4
5

plus

2
3

, These results suggest new findings about prospective teacher difficulties in conceptualizing fractions.
Diagnosis of learning difficulties in mathematics for students resolving problems related to material in the pythagorean theorem for 8th grade students in SMP 1 Todanan and SMP Muhammadiyah 9 Todanan, academic year 2018/2019
Authors: Puspitarani  , Retnawati H
Published: July 2020

This study was aimed at diagnosing the difficulties encountered by students of mathematics when problem solving Pythagorean Theorem materials, and at describing the type, location and factors of difficulty experienced by students in solving diagnostic questions of Pythagorean Theorem materials. The research used descriptive research with a qualitative approach. The research subjects were taken randomly. The most dominant type of difficulty experienced by all students in SMP Muhammadiyah 9 Todanan and in SMP 1 Todanan in completing the mathematical diagnostic test questions was in finding solutions to problems and checking answers. While the location of the difficulties experienced by students of both schools in completing the mathematical diagnostic test questions was in writing clues, problems, formulae and finding solutions to problems, they also experienced difficulties in reviewing answers and drawing conclusions. The factors that caused students difficulty in solving these test questions were as follows: Students were unable to solve the root of the results, they often forgot formulae and ways of answering the questions given. Students were not careful when solving problems and were in a rush to do so.
The effect of applying TPS type cooperative learning model assisted by SPSS software on students’ skills in IT-based statistical data analysis course
Authors: Ariawan R , Wahyuni A
Published: July 2020

This study aimed to discover the effect of applying TPS type cooperative learning models assisted by SPSS software on students’ skills in IT-based statistical data analysis course. The research method of this study was a Quasi Experiment with pretest-posttest non-equivalent multiple-group research design. The samples were selected by using the pusposive sampling technique. The samples were the sixth semester students of the Mathematics Education Study Program of FKIP Islamic University of Riau Academic Year 2018/2019, who were attending IT-Based Statistical Data Analysis course. The instrument of this research was questionnaires. The data were collected by using a non-test technique; then, the data were analyzed by applying inferential statistical analysis. Based on the results of data analysis, it was obtained that the value of Sig. 0.684 > 0.05 or H0 was accepted. Thus, it can be stated that there is no effect of the application of TPS type cooperative learning model assisted by SPSS software on students’ skills in IT-based statistical data analysis course.
Ethnomathematics: Utilizing South Sumatra’s cultures to emphasize prospective teachers’ creativity in creating mathematical problem
Authors: Araiku J , Somakim  , Pratiwi W D
Published: July 2020

This Study aims to describe prospective teachers’ creativity in producing mathematical problems based on South Sumatra’s Cultures. The subjects are 30 3rd-year mathematics study program students of Sriwijaya University. These students are divided to 8 groups of three or four. Each group assigned to create 2 mathematical problem from the same cultural context in two weeks. The results show that there is improvement for students’ fluency, flexibility, and elaboration aspect. Students are able to create more than one mathematical problems, proposes more than one resolution, and some of them are able to evaluate those alternatives. There is no significant improvement in the aspect of originality. The topic engaged with the culture tend to be uniform, with most groups employ the concept of geometry and transformation. However there is a sense of mathematical modeling in students’ works. Therefore, it is suggested to conduct further research on ethnomodeling.
Characteristics of non-compulsory mathematics test items on nationally standardized school examination in Kaimana Regency, West Papua Indonesia
Authors: Sampouw F , Retnawati H
Published: July 2020

Nationally Standardized School Examination result is used as a students’ graduation requirement. Therefore, it is absolutely necessary that its test items must be well constructed to assess. The aim of this study was to describe the characteristics of non-compulsory mathematics test items on Nationally Standardized School Examination of senior high school in Kaimana Regency, West Papua based on the items analysis. This study was a descriptive exploratory type of quantitative research. Data obtained from a set of Non-compulsory Mathematics test items including documentation of students’ answers of the following test items on Nationally Standardized School Examination of senior high school in Kaimana Regency, West Papua. A set of this test item was validated by 5 experts and analyzed by applying Classical Test Theory. Results showed that the content validity was valid for 0.9 as the average of index Aiken. The reliability of test items was in less reliable level. The items difficulty indicated that 29 items (85.3%) were hard and 5 items (14.7%) were moderate. The value of items discrimination index for 12 items (53.3%) were classified as good and 22 items (64.7%) were poor. For multiple-choice items, the distractor was made by the developer, worked effectively.
Flow-proof strategy in proof construction on geometry instruction
Authors: Scristia  , Hapizah  , Sumarni  , Araiku J
Published: July 2020

The purpose of this research is to assess the role of flowproof strategy implementation in improving students’ mathematical proof in similarity and congruence. Proofing similarity and congruence is a prerequisite in developing mathematical skills. The subjects include prospective mathematics teachers, and the study used a qualitative descriptive technique. The implementation of the flow-proof strategy was achieved through four activities, including re-writing existed information, stating what is needed to be proved, using existed rules such as postulate and definition, and writing the results in flowcharts. The findings shows that flow-proof strategy on Geometry construction was implemented appropriately, based on students’ performance in similarity and congruence proofs with percentage of 72% from all research subject.
Mathematics learning based on multiple intelligences with scientific approaches: How are their roles in improving mathematical literacy skills?
Authors: Hasmiwati  , Widjajanti D B
Published: July 2020

Having mathematical literacy skills have become a necessity for the 21st century. This ability is important to support the increasingly complex ability to solve everyday mathematical problems. Mathematics teachers must be able to choose the right learning approach to improve students’ mathematical literacy skills. The approach currently recommended is Scientific. However, not every child is intelligent in logical-mathematics. Therefore, the scientific approach needs to be implemented in the mathematics class based on the theory of multiple intelligences. This article discusses how mathematics learning based on multiple intelligence theories with a scientific approach can improve students’ mathematical literacy skills. Through a study of several theories and supported by relevant research results it can be concluded that the combination of learning based on multiple intelligence theories and scientific approaches has the potential to improve students’ mathematical literacy skills.
Self-esteem in mathematics learning: How to develop it through contextual teaching and learning approach?
Authors: Nabila L A , Widjajanti D B
Published: July 2020

Self esteem is important in learning mathematics. Self esteem is a part of self-concept that involves students in evaluation and self-assessment. But in fact in mathematics learning, there are still students who have not looked at themselves positively so resulting in students having low self esteem or lack of self confidence. Low self-esteem or lack of self-confidence can be caused by negative experiences that they had before when they studied mathematics. Whereas, self esteem has a positive effect on mathematics learning outcomes of students. There are studies that show a positive correlation between self esteem and mathematics learning achievement. Then the question is: what can a math teacher do to help students develop their self esteem? One of possible way, teachers can help students to develop their self-esteem is by applying contextual teaching and learning approach. Contextual teaching and learning approach is learning that connecting learning subject matter with everyday life. This article will discuss how to develop students’ self esteem in mathematics learning through contextual learning approach.
The perspective prospective professional teachers toward (specific) pedagogical content knowledge on derivative concept
Authors: Rosnawati R , Wijaya A , Tuharto
Published: July 2020

This study is aimed to investigate the pedagogical content knowledge of prospective professional teachers who participated in the In-service Teacher Professional Program (Program Profesi Guru Dalam Jabatan or PPG Daljab) for the topic of Derivative. The investigation into teachers’ knowledge was conducted during the phase of developing lesson plan. For this purpose, 24 in-service teachers were observed during their participation in the PPG program. The data analysis was performed for the interview results, the teachers’ lesson plan (RPP), and observation note from the peer teaching activities. The data analysis reveal that the teachers already possessed a correct conceptual understanding of derivative as indicated from their lesson plan. Nevertheless, the concepts that teachers presented in the lesson plan was still partial and did not represent a comprehensive conceptual understanding. This partial conceptual understanding was also observed during peer teaching activities. When performed a teaching simulation, teachers tended to deliver the concept in a procedural way so that the classroom activities did not fully support the development of students’ higher order thinking skills.
The analysis of mathematical communication skills in junior high school students
Authors: Ningtias S W , Sutiarso S , Caswita
Published: July 2020

This study aims to determine the students’ mathematical communication skills in the system of two-variable linear equations material. The subjects in this study were 8th grade students who were selected by purposive sampling technique. The method used in this research is descriptive. The data obtained from the students’ mathematical communication skills test consisting of 2 essay items including 3 indicators of mathematical communication skills, namely, drawing (expressing ideas into the form of images, graphs or diagrams), written text (providing the mathematical explanations in the correct language), and mathematical expression (making mathematical expressions). The test was given to 30 students of 8th grade at SMP Muhammadiyah 3 Bandar Lampung. The data were analyzed quantitatively and qualitatively to get a comprehensive picture related to the students’ mathematical communication skills. The results showed that the percentage of the achievement in each indicator of students was classified as low. This can be seen from the percentage of the achievement of the students’ mathematical communication indicators interpreted as follows, namely 1) drawing at 22%, 2) written text at 55%, and 3) mathematical expression at 12%.
Instructional media for space geometry based on augmented reality to improve students’ spatial reasoning
Authors: Pangestu A , Setyaningrum W
Published: July 2020

Technology development is growing rapidly in the 21st century. It takes a thorough preparation in various fields to deal with this condition, including in education field. Technology can be used to help learning process in the classroom particularly as an instructional media. This research aims to determine the effectiveness of instructional media of space geometry based on augmented reality in improving students’ spatial reasoning. The data were collected in one junior high schools in Yogyakarta-Indonesia. Thirty-three students of grade 8th were involved in this study. The results show that learning media is feasible to use and effective to improve students’ spatial reasoning as shown from the spatial test in which most of the students can solve the spatial reasoning tests and the spatial score were increase from 49 to 79.35 from the maximum score 100. This finding implies that AR instructional media could enhance spatial skill as it provides better visualization.
The profile of student math-anxiety
Authors: Widjajanti D B , Listyani E , Retnowati E
Published: July 2020

The main objective of this research was to describe the level of anxiety of junior high school students (SMP and MTs) towards mathematics and to identify what symptoms most appeared in students. The study conducted in 10 SMP/MTs in Kulon Progo Regency, Yogyakarta, Indonesia, representing 66 SMP/MTs in Kulon Progo. The research subjects were 943 junior high school students of grade VII, VIII, and IX from eight SMP and two MTs. Data collected through instruments in the form of a Likert model psychology scale. The conclusion of this research is as follows. First, the level of students’ anxiety towards mathematics (math-anxiety) was in a low category. Second, the percentages of students who have very low, low, moderate, high, and very high anxiety levels are 4%, 50%, 41%, 5%, and 0%, respectively. Third, the levels of anxiety of students towards mathematics are almost the same for each grade, which in the low category, except for grade VIII SMP who is in the moderate category. Fourth, psychological symptoms appear more often than physiological symptoms. Fifth, there are five questions that the most “often” and “always” answers. The items are as follows. Fist, I am relieved if the mathematics class is empty. Second, I am relieved if the math class ends”. Third, I am upset if I have to learn mathematical material without being explained first. Fourth, I am shocked if my teacher gives a lot of math homework. Fifth, I am appalled if my teacher suddenly gives a math quiz. To reduce students’ anxiety towards mathematics, it recommended for a mathematics teacher to use a humanist approach to learning.