bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of learning media using teachers of Physics Senior High School in West Sumatra with curriculum demands
Authors: Desnita  , Festiyed  , Afradisca Elfa , Sari Iis Purnama
Published: May 2020

The revised 2013 edition of the curriculum requires daily context-based physics learning and the ability to solve problems. Learning as expected will be realized if supported by the right learning media. Research has been conducted to determine the compatibility between the learning media used by senior high school Physics teachers in West Sumatera and the demands of the curriculum. Applying survey research methods, using questionnaire instruments and observation sheet. A survey of 24 unit of senior high schools in West Sumatera was conducted. Information was obtained that almost teachers in the school observed using Power Point, less than half used experiment equipment and simulation programs such as PhET only for three competencies, the rest conventional learning only using Point Power. This shows that learning does not take place in accordance with the demands of the curriculum, because the curriculum requires students as subjects and centers of learning, while learning with both media used by the teachers does not facilitate students to do or work. From the observations obtained information that laboratory equipment available in schools is not used, because it is not in accordance with the demands of the curriculum. This information shows that senior high school physics learning requires learning media in accordance with the demands of the curriculum. One of the physics learning media that is in accordance with the demands of the curriculum and millennium is based-ICT. This is contextual physics-based learning videos. This media is more appropriate because it can involve all the senses of students in learning. Therefore it is necessary to develop Contextual-based learning media.
The impact of STEM-based guided inquiry learning on students’ scientific literacy in the topic of fluid statics
Authors: Parno  , Yuliati L , Munfaridah N , Ali M , Indrasari N , Rosyidah F U N
Published: May 2020

The learning in 21st century needs literacy skill, but the study regarding the application of Science, Technology, Engineering, and Mathematics (STEM)-based Guided Inquiry (GI) to develop students’ scientific literacy is limited. This study aimed to know the impact of STEM-based GI learning on students’ scientific literacy in the topic of fluid statics. Using Pre-and Posttest design in a quasi experiment research, students in grade XI of Senior High School 7 Malang, Indonesia, were placed in two classes called Experiment (STEM-GI) and Control (conventional) classes. STEM-GI class made two engineering products, which are a small-scale hydraulic robot and hydraulic lift based on Pascal Law. The Fluid Statics Scientific Literacy Test was used to measure students’ scientific literacy with Cronbach’s alpha reliability of 0.741. Data analysis with Mann-Whitney, N-gain, and Cohen’s effect size was conducted. The result showed two classes had significantly different scientific literacy. Scientific literacy of STEM-GI was higher than conventional class. The improvement of both Experiment and Control classes belonged in medium category. The effect of operational implementation of Experiment-Control pair yielded “large” category in the enhancement of scientific literacy. From the final questionnaire, it’s revealed that students had more positive response towards STEM-based GI than conventional learning.
Exploring the effectiveness of e-book for students on learning material: a literature review
Authors: Rahim Fanny Rahmatina , Suherman Dea Stevani , Muttaqiin Arief
Published: May 2020

The process of integrating various components and activities is needed to create quality education. The effort that can be done is the innovation of teaching materials used in learning. Physics is quite difficult to master by students because it requires practicum to understand it. To make it easier for students to understand the material, it is necessary to develop an e-book containing videos, animations, and images that can support students’ understanding. Therefore, an in-depth literature review is needed to see the effectiveness of using e-book in learning.
Validity of handout development of physics education statistics course using a cooperative problem solving (CPS) model
Authors: Dewi Wahyuni Satria , Afrizon Renol
Published: May 2020

This research is a study of the validity of a teaching material in the form of a Physics Education Statistics handout. The purpose of this study was to determine the level of validity of the Physics Education Statistics handout in the UNP Physics Department from four aspects of feasibility namely content feasibility, presentation feasibility, language feasibility, and graphic feasibility. This type of research is Research and Development and was developed using the ADDIE model (Analyze, Design, Develop, Implement and Evaluate). The study of the validity of this handout is part of the Develop phase, which is done after the product in the form of a handout has been developed. The developed handout was then validated by four experts, two of whom were experts in Statistics and two others were experts in Physics Education. The data of this study were obtained from the results of the validator’s assessment in the form of a validity assessment sheet containing the four aspects of the feasibility of the handout. The results of this study indicate that the Physics Education Statistics handout using the Cooperative Problem Solving model of the four aspects of feasibility has valid and feasible quality to use, this is based on the results of expert validation that reaches 85.10 with very valid criteria.
Development of work based learning (WBL) learning model in heat transfer courses
Authors: Ambiyar  , Ganefri  , Suryadimal  , Jalinus Nizwardi , Efendi Raimon , Jeprimansyah
Published: May 2020

This 4.0 industrial evolution era requires university institution to process and result its qualified graduation using 4C approach, namely; Critical thinking, Creativity, Communication, and Collaboration. Qualification of engineering graduation is dominantly determined by learning model applied in the class such as Work Based Learning. The Work Based Learning Model is a change of learning system from conventional system in the class into a system placing the education into work place, in this case is in laboratory. This system combines institutional learning pattern in classroom by real equipment in the laboratory so that it can result in integrated experiences between theories and real practices by students. Basically, WBL is a learning model approach using work place as a media to transfer learning knowledge. During student period of learning on heat transfer course, it only describes theoretical information description in uncritical learning process, less creative, passive communication and no inter-student collaboration. There are many various models studied by experts to identity any components having influences on making successful WBL. This article tries to identify and review the development of work based learning models that will be applied to the Department of Mechanical Engineering at Bung Hatta University.
Need analysis development of learning model based on production in multimedia materials in higher education
Authors: Ganefri  , Yulastri Asmar , Ambiyar  , Jeprimansyah  , Suryadimal
Published: May 2020

This study aims to develop a product-based learning model in the Multimedia course at the Information Management D3 Study Program at Mahaputra University Muhammad Yamin Solok. The product of its development is a production-based learning model which is the development of the syntax of a product-based learning model. Development carried out on syntax arrangement and addition of parts in the production process by completing learning activities on promotions and trade based online. a production-based learning model that contains guidelines for using models that have been developed for lecturers. This study uses Research and Development (R and D) research methods, and the development model using ADDIE instructional. The data analysis technique uses descriptive techniques by describing the prevalence and practicality and effectiveness
Analysis of basic electronics 2 textbook reviewed from the aspects of creative thinking in the Physics Department of FMIPA UNP Padang
Authors: Hufri  , Silvi  , Sari Yulia , Triani Frima , Syahrani Filda , Ceria Hening , Noer Fadhlina
Published: May 2020

This study aims to determine the development of the ability to think creatively in basic electronic textbook 2 used in the physics department of the FMIPA, UNP Padang. This research is a descriptive study that aims to obtain information about the development of creative thinking skills in the two textbooks used. Data collection uses analysis instruments, aspects of creative thinking. The results showed that the book used has facilitated aspects of creative thinking of its College students. The ability to think creatively facilitated includes fluency with an average of 35.79%, flexibility with an average of 20, 30%, originality with a mean of 12.21% and elaboration with an average of 31.70%. But the textbook used is not optimal in facilitating the development of college students’ creative thinking abilities.
Validity of student worksheets based on inquiry based learning models assisted by tracker application
Authors: Fadilah Rizki , Yohandri  , Yulkifli
Published: May 2020

This study aims to determine the validation of student worksheets based on inquiry based learning models assisted by tracker application on momentum and impulse material of high school physics learning. This research method uses research and development with a model Plomp. A data collection instrument using a validity sheet previously validated bay three validators. The results of the validation analysis sheet show worksheet based on inquiry based learning models assisted by tracker application developed with a valid criteria.
Validity of student’s worksheets based on project based learning assisted tracker application
Authors: Lismidarni Susri , Yohandri
Published: May 2020

This research was motivated by demands of the curriculum 2013 which states that learning physics should ideally be presented by presenting facts, objects, or the phenomenon of physics directly to students. For this reason, it was necesssary to development an innovation in the form of developing learning models, learning resources and learning media that are in accordance with demands of the curriculum 2013, including learning resources in the form easily understood LKPD and can help students to learn independently, project based learning with a scientific approach to improved student’s skills and tracker applications are the use of tecnological development so that students could be Internationally competitive. The purpose of this study was to validity of student’s worksheets based on project based learning model assisted tracker application with valid criteria. This type of research is development research using plomp model with stage preliminary research, development or prototyping phase, and assesment phase (semisummative evaluation). The result ot the analysis of students need a LKPD as a learning resource and a project based learning model as a learning model and technology utilization with a tracker application. The result of the development stage was produced by a valid LKPD with a criteria (≥0,6) and used in the implementation stage.
Integration of environmental education in elementary schools
Authors: Sukma E , Ramadhan S , Indriyani V
Published: May 2020

This study aims to determine the opinions and knowledge of teachers regarding the integration of environmental education in the learning process in the classroom for elementary school students. This research uses survey method. The instrument used was a questionnaire consisting of fifteen questions and four additional statements relating to environmental education in the learning process. The results showed that the majority of teachers agreed that it was important to integrate environmental education in the learning process for students, especially elementary school students. However, this integration still has constraints, such as insufficient time. Based on the results of the analysis shows that for elementary school level, science learning is the most likely learning to be integrated with environmental education in the learning process.
Pressure distributions on swept/unswept wings using pressure sensitive paint
Authors: Huang Y.X. , Wu H.Y. , Chung K. M. , Chang K.C.
Published: May 2020

Pressure sensitive paint (PSP) is an optical-based technique for full-field pressure measurements. A polymer-ceramic PSP, Ru(dpp), with a porous material is used and is applied onto a Mylar tape which affixed to the model surface of NACA 0012 and ONERA M6 wings. The PSP results agree with the data using conventional pressure measurements reasonably well.
Using Matlab real-time image analysis for solar panel fault detection with UAV
Authors: Liao K C , Lu J H
Published: May 2020

The main purpose of this study is to evaluate the feasibility to use Unmanned Aerial Vehicle (UAV) technology for solar panel applications and to propose a reliable, economical and fast method of fault detection. In this experiment, the UAV was used to inspect the panels of a solar farm. For this purpose, a set of tools were selected including an infrared camera and a High Definition (HD) photographic lens to scan solar panel assembly. The infrared images were immediately transmitted back with backhaul HD for analysis. The infrared image display can be roughly divided into three health conditions. The first one is the normal operation of the solar panel. In the second case, the infrared image represents an abnormal situation of the solar panel. The third one is a blurred case in which the infrared image cannot be determined to be normal or abnormal. Under this kind of situation, the Matlab® image analysis was used in this study to determine the health condition of solar panels. The results show that it is effective and efficient to use UAV to capture the thermal image and to detect different faults of solar modules. Moreover, this process is fast, low cost, and can detect defects that are not noticeable by visible light. It may provide maintenance personnel with a tool to prevent solar module failure.
Experimental measurement of anisotropic thermal conductivity of 18650 lithium battery
Authors: Huang Jian , Xu Peichen , Wang Peiyong
Published: May 2020

The accurate thermal conductivity of the 18650 cell is essential to the thermal management of the battery pack for electronic vehicles and aircrafts. The structure of the cell makes the conductivity anisotropic. Judged from the cell structure, the azimuthal and axial conductivity are approximately the same while the radial conductivity is much different from them. The axial conductivity of a cell is calculated by supplying an axial steady heat rate through the cell and measuring the axial temperature difference over the cell. For the radial conductivity, a steady heat rate is supplied on one quarter of the cylindrical outer surface of the cell, the heat crosses the cell radially and azimuthally to the opposite quarter of the cylindrical outer surface. The temperature difference of the two quarter surfaces is measured, and the radial conductivity of the cell is determined by adjusting the radial conductivity value with known azimuthal conductivity (equals to the axial conductivity) in an accurate CFD heat transfer simulation to match the measured temperature drop.
Fabrication and Strength Assessment of Composite Corrugated Expansion Tube
Authors: Liu J.W. , Kam T.Y.
Published: May 2020

A technique is proposed to develop a composite corrugated expansion tube which can achieve a prescribed axial extension when subjected to an internal pressure. The composite corrugated expansion tube was fabricated using annular carbon fabric/PU sheets via the vacuum-assisted resin transfer process. In forming the tube shape, the edges of each annular fabric/PU sheet are adhesively bound to the other two similar sheets at the outer and inner edges, respectively. A finite element model of the corrugated expansion tube is established using the shell elements of the finite element code ANSYS. To illustrate the applications of the proposed technique, the corrugated expansion tube that can sustain internal pressure of 82.73 MPa is developed and tested to verify the accuracy of the finite element model. It has been shown that compressive stresses are induced at the adhesive layers that are located at the outer edges of the corrugated expansion tube. The occurrence of such compressive stresses at the outer edge adhesive layers can increase the failure pressure of the corrugated expansion tube. The failure strength of the composite sheet dominates the incipient failure pressure of the tube. This type of failure mode makes the expansion tube design feasible for practical applications.
Improved genetic algorithm with two-level multipoint approximation for complex frame structural optimization
Authors: Ren Xingyu , Fu Jiayi , Huang Hai
Published: May 2020

In this paper, an improved structural topology and sizing optimization method is developed for the fast and efficient engineering design of complex frame structures where beam elements are mainly used in the structures. Discrete and continuous variables are included that the elimination or existence of beam elements are treated as discrete variables (0,1), and the continuous sizing variables of beam cross sections are considered to be continuous variables. To solve the mixed variable problem, the paper introduces a two-level multipoint approximation strategy (TMA). The first-level approximate problem is established by using the branched multipoint approximate function, which includes both two types of variables. Genetic algorithm (GA) is used to determine the absence or presence of beam members. The second-level approximate problem that only involving retained continuous size variables is made on this basis, which uses Taylor expansion and dual methods to solve the inner layer continuous optimization problem. Meanwhile, a strategy of adding a new complementary design point is adopted to expend the search scopes and improve the precision. Temporal deletion techniques are used to temporarily remove redundant constraints and local vibration modes processing techniques are used for continuum topology optimization under frequency constraints. Several representative examples are investigated to validate the effectiveness of the improved method.
Lateral Stability and Control of a Flying Wing Configuration Aircraft
Authors: Wang Yankui , Tang Xiangxi , Li Tao
Published: May 2020

A numerical investigation was conducted on an Unmanned Combat Air Vehicle (UCAV) model which is a moderately swept, tailless and flying wing configuration. A wind tunnel test was performed to validate the numerical results. Model forces and moments were measured using a six-component strain-gauged force balance. The computations were performed using a commercial Reynolds-Averaged Navier-Stokes (RANS) flow solver. The numerical results show that the lateral unstable of the model is caused by asymmetrical breakdown of the body vortex, and the flaps installed can induce earlier breakdown and intensity loss of the leeward vortex resulting in the enhancement of lateral stability.
Numerical simulation of dynamic multi-body separation flowfields
Authors: Han Bing , Gao Zhenxun , Jiang Chongwen
Published: May 2020

In this paper, three-dimensional unsteady Navier-Stokes equations coupled with six-degree-of-freedom equations are solved numerically to simulate the process of multi-body separation in the condition of high speed and high altitude. Overset grids are adopted to deal with the relative motion between two different parts. In order to study the security of separating process, the trajectories and attitudes of different parts are calculated and the characteristics of flow field during separation are analyzed carefully. Different initial angles of attack are considered during the simulation and its influence on the separation process is analyzed. The result shows that the initial angle of attack has significant impact on the flow field. Large angle of attack would cause shock/shock interactions between the two parts, threatening the safety of the separating process.
Numerical prediction of aerodynamic performance for open geometry centrifugal compressor
Authors: Kawahara Takahiro , Yamasaki Nobuhiko
Published: May 2020

Numerical prediction of aerodynamic performance of compressors has been widely performed by the RANS model, but there is the tendency to overestimate the work and efficiency of the impeller of a centrifugal compressor. In the RANS, we cannot analyze unsteady phenomena such as tip leakage flow. On the other hand, the LES models universal region of turbulence by performing spatial filtering operations. Since it does not include the concept of time averaging, it can be applied to unsteady calculations. In this paper we perform numerical prediction of aerodynamic performance by the RANS with the Spalart-Allmaras turbulence model and the LES with the Smagorinsky model, and reveal the unsteady phenomena, which cannot be analyzed by the RANS, by comparing each result. The CFD solver that we use is “UPACS”, which JAXA (Japan Aerospace Exploration Agency) has developed. We clarify its prediction accuracy and problem points of UPACS. The geometry data of the centrifugal compressor that we analyze is published in the papers written by Krain. The compressor is equipped with impeller with 24 full blades and vaneless diffuser. Comparing computed characteristic curves of mass-averaged total pressure, using the LES improves the overestimation of the total pressure ratio by the RANS by 10%. It seems that the LES can analyze the unsteady phenomena which the RANS cannot.
Design and implementation of a dual-antenna GPS receiver
Authors: Lin Y Y , Hsu T H , Chen T L
Published: May 2020

In the Global Position System (GPS) technology, the GPS receiver (GPSR) has to receive the satellite signal to locate its position in a 3D space. For the GPS applications where the GPSR carrier (vehicle) is rotating, the signal-receiving-path could be temporally blocked by the attitude of the vehicle. And, once the GPSR loses track of the signal, it takes at least 6 seconds for the GPSR to resume its positioning task. This paper proposes a novel dual-antenna GPSR system (hardware architecture and algorithms) that can solve the intermittent signal problem when the vehicle is rotating and continuing on its positioning task. Current experimental results indicate that the proposed GPSR design can successfully output its position when the vehicle is rotating at 7.5 rpm. At 22 rpm, some satellite signals remain on-lock but some do not, depending on the strength of receiving signals.
Fault diagnosis method for worm gearbox using convolutional network and ensemble learning
Authors: Hsiao J C , Shivam Kumar , Kam T Y
Published: May 2020

Worm gearboxes are popular across various industrial applications since they offer significant gear ratios in small installation spaces. Despite having multiple advantages, worm gearboxes are subjected to higher friction due to sliding design and are prone to damage and increased transmission error over the period of operation. Delayed diagnosis of worm gearbox degradation can lead to low-quality products and/or unnecessary production line downtime. Using vibration characteristics of worm gearbox, it is possible to determine the fault and transmission error at a given period in time. In this paper, an ensemble machine learning model is trained and deployed to monitor the transmission error of worm gearbox and classify between new, operational and old conditions. 1D CNN (one dimensional convolutional neural network) model is used to automatically extract features in vibration signal of X, Y, and Z axes and predict the relevant state of worm gear. The proposed technique uses ensemble machine learning technique fusion of features extracted by multi-layer 1D CNN for three axes vibration data. The proposed method could achieve 96% accuracy and performs significantly better than traditional sequential and ensemble machine learning models on a dataset of with 7,870 samples with 800 samples labeled as new condition, 4,740 samples as operational and 2,330 as old.
Formulation of mashed potatoes (Solanum tuberosum L.) as Tengger culinary product
Authors: Perdani C G , Wijana S , Yamin A
Published: May 2020

Indonesia is one of the tourist destination countries because of its natural beauty. Bromo Tengger Semeru National Park (TNBTS) is one of the destinations that becomes the main destination of tourists. In addition to natural attractions, culinary tourism can be an alternative in developing the tourism industry of TNBTS. A local cuisine has an important role to attract the hearts of tourists because they will be interested to try the local cuisine. Potato is one of the leading commodities in Ngadas Village TNBTS. The objective of this research was to obtain the optimal formulation of the mashed potato product. In this research, the linear programming was used as an optimisation analysis. The objective function was to minimise the cost of mashed potatoes production. The design of mashed potato composition was made of 4 types: formulation A (using cassava starch), composition B (using rice starch), C composition (using corn starch) and D composition (without using starch). The best treatment obtained was the addition of corn starch. Preparation of 100 g of mashed potato was made with 50 g of mashed potato, 20 g corn starch, 13 Ml water, 5 g of milk powder, 4 g of cheese and the rest were salt and pepper. The average value of the hedonic test on the addition of corn flour was 4.85 (acceptance). The cost of making 200-gram mashed potatoes was IDR 5,038.00.
Production of biodegradable package material from tofu industry byproduct
Authors: Antonius R , Simamora L L B , Setiani P , Sitorus T A , Luthfiyana H , Idris Z Y
Published: May 2020

Plastic has been widely used as single-use package and carrier material due to its low price, strength, practicality, and versatility. On the other hand, plastic requires a long period to naturally decompose. Nowadays, a huge number of plastic wastes have caused detrimental impacts to the global environment, hence a more environmentally benign substance of making plastic is a significant importance. This study proposed the production of biodegradable material from nata de soya, which is composed from whey waste using melt intercalation method. This environmentally-friendly substance was mainly obtained from tofu industry byproduct which is known as ‘whey’, through fermentation process using Acetobacter xylinum bacteria. Melt intercalation method was used to obtain desired texture and characteristic, the step was the fermented product mixed with chitosan, acetic acid, glycerol, and tapioca starch, with various range of concentration. The mixed component then underwent milling and drying process for finalization. As for characteristic of the materials, tested parameters include solubility, water resistance, and biodegradability in the environment. Our results showed the potential of this material to substitute the use of plastic and is applicable for versatile purposes. Water resistance was up to 95 minutes, and the material was able to be completely degraded in around 60 days.
Study of sensitivity for strain-based structural health monitoring
Authors: Herrera-Iriarte A , Alvarez-Montoya J , Sierra-Pérez J
Published: May 2020

One of the available methodologies for structural health monitoring (SHM) is based on strain field pattern recognition where, through the use of sensors capable of measuring strain on discrete points and machine learning techniques, it is possible to detect a damage event. In this study, strain data from fiber optic sensors (FOS), in particular fiber Bragg gratings (FBG), acquired through two experiments are used: an aluminum beam with 32 FBGs and CFRP beam provided with 20 FBGs, which serves as the main wing’s structure of an unmanned aerial vehicle (UAV). Both structures were subjected to dynamic loading for a pristine condition and later, for artificially damaged conditions. In the experiments presented in this paper the beams were provided with different amounts of sensors which were removed one by one in order to analyze the sensitivity of the damage detection methodology based on PCA to a change in the number of sensors. The results demonstrated that there are few sensors that contribute mostly to the methodology’s performance, these sensors are validated to be the ones located near the analyzed damage condition. Therefore, this study is the first step into the development of methodologies of damage localization using strains.
Probabilistic analysis of fatigue crack growth using efficient surrogate model
Authors: Chahine S , Riahi H , Bigaud D
Published: May 2020

In this paper probabilistic analysis of a fatigue crack growth process governed by the Walker law is performed. Sensitivity of its parameters to uncertainties related to the material properties is considered. Based on statistical analysis of experimental data, they are modelled as independent normal random variables. The effect of these uncertainties on the fatigue crack growth behaviour of Centre Cracked Plate specimen is assessed using Monte-Carlo simulations and surrogate model based on polynomial chaos expansion. An efficient truncation scheme allows to discard the high order interactions having a weak effect on the mechanical response and consequently reduce the number of finite elements calls when identifying the unknown coefficients of the polynomial chaos expansion. The statistical moments namely the mean and the standard deviation in addition to the probability density function of the mechanical response are derived with a good accuracy. The obtained results show that the fatigue crack growth life is significantly affected by the uncertainties on the material properties since its coefficient of variation reaches 21% and that it follows a log-normal distribution law.
Decision support system for quality management of cosmetic products
Authors: Shabunina O.V. , Khalyasmaa A.I. , Korelina E.V.
Published: May 2020

The paper describes the structure and the mathematical core of the decision support system developed by the authors for assessing the quality of cosmetic products based on machine learning approaches. The main goal of the study was to improve the system of quality control of cosmetic products, in particular, the quality of perfumes and cosmetics using intelligent methods of data processing, formalization of knowledge and experience of the experts, thus providing automatization of the decision-making process. The practical-oriented goal of the study was to obtain knowledge-supported decisions regarding the quality of the cosmetic products using the developed system of quality assessment based on intelligent methods of data processing, providing the possibility of unsupervised learning and adjustment of the developed system when changing final product characteristics.
Topological theory of physical fields
Authors: Jafari Amir , Vishniac Ethan
Published: May 2020

We study the topology associated with physical vector and scalar fields. A mathematical object, e.g., a ball, can be continuously deformed, without tearing or gluing, to make other topologically equivalent objects, e.g., a cube or a solid disk. If tearing or gluing get involved, i.e. the deformation is not continuous anymore, the initial topology will consequently change giving rise to a topologically distinct object, e.g., a torus. This simple concept in general topology may be employed in the study of physical systems described by fields. Instead of continuously deforming objects, we can take a continuously evolving field, with an appropriately defined topology, such that the topology remains unchanged in time unless the system undergoes an important physical change, e.g., a transition to a different energy state. For instance, a sudden change in the magnetic topology in an energetically relaxing plasma, a process called reconnection, strongly affects the dynamics, e.g., it is involved in launching solar flares and generating large scale magnetic fields in astrophysical objects. In this topological formalism, the magnetic topology in a plasma can spontaneously change due to the presence of dissipative terms in the induction equation which break its time symmetry. We define a topology for the vector field

F

in the phase space

(
x
,
F
)

. As for scalar fields represented by a perfect fluid, e.g., the inhomogeneous inflaton or Higgs fields, the fluid velocity

u

defines the corresponding topology. The vector field topology in its corresponding phase space

(
x
,
F
)

will be preserved in time if certain conditions including time reversal invariance are satisfied by the field and its governing differential equation. Otherwise, the field’s topology can suddenly change at some point, similar to a spontaneously broken symmetry, as time advances, e.g., corresponding to an energy transition.
Invited Commentary: Frontiers of Power Assessment in Mediation Analysis
Authors: VanderWeele Tyler J
Published: May 2020

The development of tools for power and sample-size calculations for mediation analysis has lagged far behind the development of methods. The accompanying paper by Rudolph et al. (Am J Epidemiol. 2020;189(12):1559–1567) is a helpful contribution in using simulations as a tool for power calculations for more complex methods and settings. Much work remains to be done in the development of easy-to-use packages and simple online websites for carrying out power and sample-size calculations for mediation analysis. Much remains to be learned with respect to the relative power of different methods in different settings. There will likely be feedback between these 2 important frontiers of the tools we have available and of our understanding of power when conducting mediation analysis.
Relationship of Socioeconomic Status to Arterial Stiffness: Comparison Between Medical Aid Beneficiaries and National Health Insurance Beneficiaries
Authors: Kim Hack-Lyoung , Lee Jin Yong , Lim Woo-Hyun , Seo Jae-Bin , Kim Sang-Hyun , Zo Joo-He , Kim Myung-A
Published: May 2020

Background

There is no general agreement on underlying pathophysiology explaining the high burden of cardiovascular disease on people at low socioeconomic status (SES). This study was conducted to investigate the association between healthcare systems and arterial stiffness.

Methods

A total of 8,929 subjects (60 years old and 55% were male) who underwent brachial-ankle pulse wave velocity (baPWV) measurement were retrospectively analyzed. There were 8,237 National Health Insurance (NHI) beneficiaries (92.2%) and 692 medical aid (MA) beneficiaries (7.8%). The median value of baPWV was 1,540 cm/s.

Results

Subjects with higher baPWV values (≥1,540 cm/s) were older, and more frequently had cardiovascular risk factors and unfavorable laboratory findings than those with lower values baPWV (<1,540 cm/s). The baPWV values were significantly higher in MA beneficiaries than in NHI beneficiaries (1,966 ± 495 vs. 1,582 ± 346 cm/s, P < 0.001). The proportion of MA beneficiaries was significantly higher in subjects with higher baPWV than those with lower baPWV (13.1% vs. 2.3%, P < 0.001). In multivariable analysis, MA beneficiaries were significantly associated with higher baPWV values even after controlling for potential confounders (odds ratio, 5.41; 95% confidence intervals, 4.02–7.27; P < 0.001).

Conclusions

The baPWV values were significantly higher in MA beneficiaries than in NHI beneficiaries. The result of this study provides additional evidence on the association between low SES and arterial stiffening.
Universal Face Masking Reduces Respiratory Viral Infections Among Inpatient Very-Low-Birthweight Neonatal Infants
Authors: Tong Wing Yee , Yung Chee Fu , Chiew Lee Chern , Chew Siong Beng , Ang Li Duan , Thoon Koh Cheng , Rajadurai Victor S , Yeo Kee Thai
Published: May 2020

We reviewed the impact of a universal face masking policy on respiratory viral infections (RVIs) among admitted very-low-birthweight infants in our neonatal department. There was a significant decrease in RVI incidence, specifically in our step-down level 2 unit, with respiratory syncytial virus and parainfluenza virus being the most common viruses isolated.
Acute peritoneal dialysis in the treatment of COVID-19-related acute kidney injury
Authors: Ponce Daniela , Balbi André L , Durand Jonathan B , Moretta Gustavo , Divino-Filho José C
Published: May 2020

The kidney is not typically the main target of severe acute respiratory syndrome coronavirus 2, but surprisingly, acute kidney injury (AKI) may occur in 4–23% of cases, whereas the dialysis management of AKI from coronavirus 2019 has not gained much attention. The severity of the pandemic has resulted in significant shortages in medical supplies, including respirators, ventilators and personal protective equipment. Peritoneal dialysis (PD) remains available and has been used in clinical practice for AKI for >70 years; however, it has been used on only a limited basis and therefore experience and knowledge of its use has gradually vanished, leaving a considerable gap. The turning point came in 2007, with a series of sequential publications providing solid evidence that PD is a viable option. As there was an availability constraint and a capacity limit of equipment/supplies in many countries, hemodialysis and convective therapies became alternatives. However, even these therapies are not available in many countries and their capacity is being pushed to the limit in many cities. Evidence-based PD experience lends support for the use of PD now.
Supportive wind conditions influence offshore movements of Atlantic Coast Piping Plovers during fall migration
Authors: Loring Pamela H , McLaren James D , Goyert Holly F , Paton Peter W C
Published: May 2020

In advance of large-scale development of offshore wind energy facilities throughout the U.S. Atlantic Outer Continental Shelf (OCS), information on the migratory ecology and routes of federally threatened Atlantic Coast Piping Plovers (Charadrius melodus melodus) is needed to conduct risk assessments pursuant to the Endangered Species Act. We tagged adult Piping Plovers (n = 150) with digitally coded VHF transmitters at 2 breeding areas within the southern New England region of the U.S. Atlantic coast from 2015 to 2017. We tracked their migratory departure flights using a regional automated telemetry network (n = 30 stations) extending across a portion of the U.S. Atlantic Bight region, a section of the U.S. Atlantic coast, and adjacent waters of the Atlantic Ocean extending from Cape Cod, Massachusetts, to Cape Hatteras, North Carolina. Most adults departed within a 10-day window from July 19 to July 29, migrated nocturnally, and over 75% of individuals departed within 3 hr of local sunset on evenings with supportive winds. Piping Plovers migrated offshore directly across the mid-Atlantic Bight, from breeding areas in southern New England to stopover sites spanning from New York to North Carolina, USA, over 800 km away. During offshore migratory flights, Piping Plovers flew at estimated mean speeds of 42 km hr−1 and altitudes of 288 m (range of model uncertainty: 36–1,031 m). This study provides new information on the timing, weather conditions, routes, and altitudes of Piping Plovers during fall migration. This information can be used in estimations of collision risk that could potentially result from the construction of offshore wind turbines under consideration across large areas of the U.S. Atlantic OCS.
Training Requirements, Automation, and Job Polarisation
Authors: Feng Andy , Graetz Georg
Published: May 2020

We analyse how job training requirements interact with engineering complexity in shaping firms’ automation decisions. A model that distinguishes between a task’s engineering complexity and its training requirements predicts that when two tasks are equally complex, firms automate the task that requires more training. Under plausible conditions this leads to job polarisation, and in particular to polarisation of employment by initial training requirements. US data provide empirical support for the model’s implications. Training requirements and a measure of engineering complexity account for much of US job polarisation from 1980 to 2008.
Effect of oral consumption of capsules containing Lactobacillus paracasei LPC-S01 on the vaginal microbiota of healthy adult women: a randomized, placebo-controlled, double-blind crossover study
Authors: Koirala Ranjan , Gargari Giorgio , Arioli Stefania , Taverniti Valentina , Fiore Walter , Grossi Elena , Anelli Gaia Maria , Cetin Irene , Guglielmetti Simone
Published: May 2020

Oral consumption of probiotics is practical and can be an effective solution to preserve vaginal eubiosis. Here, we studied the ability of orally administered Lactobacillus paracasei LPC-S01 (DSM 26760) to affect the composition of the vaginal microbiota and colonize the vaginal mucosa in nondiseased adult women. A total of 40 volunteers took oral probiotic (24 billion CFU) or placebo capsules daily for 4 weeks, and after a 4-week washout, they switched to placebo or probiotic capsules according to the crossover design. A total of 23 volunteers completed the study according to the protocol. Before and after capsule ingestion, vaginal swabs were collected for qPCR quantification to detect L. paracasei LPC-S01 and for 16S rRNA gene sequencing. Vaginal swabs were grouped according to their bacterial taxonomic structure into nine community state types (CSTs), four of which were dominated by lactobacilli. Lactobacillus paracasei LPC-S01 was detected in the vagina of two participants. Statistical modeling (including linear mixed-effects model analysis) demonstrated that daily intake of probiotic capsules reduced the relative abundance of Gardnerella spp. Quantitative PCR with Gardnerella vaginalis primers confirmed this result. Considering the pathogenic nature of G. vaginalis, these results suggest a potential positive effect of this probiotic capsule on the vaginal microbial ecosystem.
Geodetic evidence for a buoyant mantle plume beneath the Eifel volcanic area, NW Europe
Authors: Kreemer Corné , Blewitt Geoffrey , Davis Paul M
Published: May 2020

The volcanism of the Eifel volcanic field (EVF), in west-central Germany, is often considered an example of hotspot volcanism given its geochemical signature and the putative mantle plume imaged underneath. EVF's setting in a stable continental area provides a rare natural laboratory to image surface deformation and test the hypothesis of there being a thermally buoyant plume. Here we use Global Positioning System (GPS) data to robustly image vertical land motion (VLM) and horizontal strain rates over most of intraplate Europe. We find a spatially coherent positive VLM anomaly over an area much larger than the EVF and with a maximum uplift of ∼1 mm yr−1 at the EVF (when corrected for glacial isostatic adjustment). This rate is considerably higher than averaged over the Late-Quaternary. Over the same area that uplifts, we find significant horizontal extension surrounded by a radial pattern of shortening, a superposition that strongly suggests a common dynamic cause. Besides the Eifel, no other area in NW Europe shows significant positive VLM coupled with extensional strain rates, except for the much broader region of glacial isostatic adjustment. We refer to this 3-D deformation anomaly as the Eifel Anomaly. We also find an extensional strain rate anomaly near the Massif Central volcanic field surrounded by radial shortening, but we do not detect a significant positive VLM signal there. The fact that the Eifel Anomaly is located above the Eifel plume suggests that the plume causes the anomaly. Indeed, we show that buoyancy forces induced by the plume at the bottom of the lithosphere can explain this remarkable surface deformation. Plume-induced deformation can also explain the relatively high rate of regional seismicity, particularly along the Lower Rhine Embayment.
The effect of gender and educational level on dictionary use strategies adopted by upper-elementary and lower-secondary students attending Greek Schools1
Authors: Chadjipapa Elina , Gavriilidou Zoe , Markos Angelos , Mylonopoulos Antonis
Published: May 2020

The aim of the present large-scale study is to elaborate on the concept of ‘Dictionary Use Strategy’ (DUS), to investigate the effect of gender and educational level on DUSs adopted by upper elementary and lower secondary students in Greek mainstream schools, and to determine the strategic profile of the sample by using a standardized instrument of data collection. The sample consisted of 745 upper elementary and lower secondary pupils in Greek mainstream education to whom the Strategy Inventory for Dictionary Use (S.I.D.U.) was administered. Results indicate that the adoption of dictionary use strategies is significantly influenced by both educational level and gender. Results are discussed in connection with the effectiveness of dictionary use and the influence of gender and educational level on learning strategy use.
Towards a just Internet access: republican net neutrality for the EU
Authors: Rochel Johan
Published: May 2020

The issue of net neutrality has been the object of intense policy-making effort in EU institutions and in EU Member States. These efforts have led to the entry into force of EU Regulation 2015/2120 in 2016. This article aims to contribute to both legal discussion on this EU legislation and philosophical discussion on net neutrality. It relies upon a methodological approach conceived as a dialogue between law and political philosophy. The main hypothesis of this article is that ‘net neutrality’ is an open concept crystallizing distinct normative challenges. In order to address them, I develop a two-fold argument: first, identify underlying values and, second, use them as interpretative guidelines for legal norms. I will propose a republican understanding of the values at stake in the different traffic management measures addressed by EU Regulation 2015/2120. This republican approach is based on the definition of freedom as the absence of domination. I will show how this approach might be productive in interpreting EU regulations.
Characteristic Polynomials of Complex Random Matrices and Painlevé Transcendents
Authors: Deaño Alfredo , Simm Nick
Published: May 2020

We study expectations of powers and correlation functions for characteristic polynomials of $N \times N$ non-Hermitian random matrices. For the $1$-point and $2$-point correlation function, we obtain several characterizations in terms of Painlevé transcendents, both at finite $N$ and asymptotically as $N \to \infty $. In the asymptotic analysis, two regimes of interest are distinguished: boundary asymptotics where parameters of the correlation function can touch the boundary of the limiting eigenvalue support and bulk asymptotics where they are strictly inside the support. For the complex Ginibre ensemble this involves Painlevé IV at the boundary as $N \to \infty $. Our approach, together with the results in [ 49], suggests that this should arise in a much broader class of planar models. For the bulk asymptotics, one of our results can be interpreted as the merging of two “planar Fisher–Hartwig singularities” where Painlevé V arises in the asymptotics. We also discuss the correspondence of our results with a normal matrix model with $d$-fold rotational symmetries known as the lemniscate ensemble, recently studied in [ 15, 18]. Our approach is flexible enough to apply to non-Gaussian models such as the truncated unitary ensemble or induced Ginibre ensemble; we show that in the former case Painlevé VI arises at finite $N$. Scaling near the boundary leads to Painlevé V, in contrast to the Ginibre ensemble.