bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review on Methods to Improve and Balance the Assembly Line
Authors: Kharuddin M H , Ramli M F
Published: March 2020

Assembly line is well known as an important part in manufacturing process. It consists of several workstations that linked together to create a complete product. Each of workstation is doing their own tasks. However, during the process of item moving from workstation to another workstation to become a finished product, the unbalance of workload among workstation will create a bottleneck effect. This problem will cause the performance of assembly line is not optimal. Therefore, to improve the performance of assembly line, many methods are applied and used to solve assembly line balancing problem. In this paper, different methods which can be used to improve and balance the assembly line are discussed.
Investigation on the Effect of Deflected Ground Structure in Multi-Direction Steerable Antenna for WSN
Authors: Zainudin N A F M , Osman M N , Sabapathy T , Jusoh M
Published: March 2020

In this paper, a multi-direction steerable radiation pattern antenna is designed and investigated, which operates at 2.45 GHz frequency. The radiation pattern reconfigurable is achieved by locating four parasitic elements surrounding the driving element at the centre. The artificial switches, are currently used to replace the ideal diode for proof of the concept, are inserted at the specific position on the parasitic element. By controlling the state ON/OFF of the switches, the parasitic is grounded via shorting pin, thus realizing the beam steering to be directed into four direction angles; right, left, upwards and downwards. In this research, an investigation on the effect of deflected ground plane on the steering angles has been carried out. With minimum numbers of switches deployed, the proposed antenna is a potential candidate to serve as a transmitting element in WSN applications.
Determination of soft starter firing angle performance to mitigate motor high inrush current using current limitation method
Authors: Abdul Rahim Mohamad Shukor , Azizan Muhammad Mokhzaini , Yusoff Mohd Irwan , Mat Mohd Hafizuddin , Binti Ahmad Nur Irwany , Binti Fadzail Noor Fazliana , Md Esa Suhaireza Binti
Published: March 2020

Inrush current in the simplest form can also be determined as current drawn by an induction motor during startup period. This starting current will shoot up about 5 to 7 times the rated current. However, this high current usually occur in the starting period only. To overcome this, several techniques can be implemented to reduce the high current. The configuration of soft starter just involving some power semiconductor device act as switches that control the current flow from power source to the motor. The switches is in form of thyristor and are connected back-to-back because the system conduct in AC system. The current output can be controlled by varying the firing angle. This changing of firing angle will be managed by a firing angle control circuit. This soft starter was connected between power source and motor. The thyristors that built in soft starter act like a gate to control the voltage applied to the motor. The firing angle for current limitation soft starter was changed to several angle and what can be concluded that the high current succeed to mitigate with increasing the firing angle. The current drawn for this type of starter is steadily constant. The lower current during starting took longer time for motor to reach its rated speed. This type of starter successfully reduces inrush current about 42 percent. Finally what can be concluded is that the soft starter was proven to mitigate inrush current. Type of soft starter that going to implement is depending on the application of motor. When the application need to control the torque is more suitable to use current limitation soft starter because the current is steadily control.
Design and on-body evaluations of a low-cost wearable PIFA for on-body applications
Authors: Ahmadihaji Azadeh , Aliakbarian Hadi , Saaid Nordiana Mohamad , Soh Ping Jack
Published: March 2020

A flexible low profile textile antenna based on planar inverted-F antenna (PIFA) structure is presented in this paper. This topology has been chosen due to its design simplicity, relatively large bandwidth and the existence of a full rear ground plane, which shields against the effects of the body. The antenna topology which is designed on a 4 mm-thick felt substrate is presented. Conductive textile (Aaronia-shield) is applied as the antenna’s radiator and ground plane due to its light weight, low surface resistance and good conductivity. The antenna performance in free space and bent conditions in the proximity of human body are studied, followed by a numerical investigation on the influence of relative humidity on the textile antenna performance. The fabricated PIFA is assessed experimentally and is found to be in good agreements with the simulation results. Finally, the antenna is attached to a compact RF module and is evaluated on body in a practical environment. The wireless link quality is also evaluated in an indoor laboratory environment.
An Identification of Software Requirement for Web Based Judging System
Authors: Zahari N.A.A. , Gining R.A.JM. , Fauzi S.S.M. , Razak T.R. , Jamaluddin M.N.F.
Published: March 2020

The paper aims to identify the requirement for the judging system. The requirement identification of the system involves two phases; requirement gathering and requirement analysis. Several activities are done in each of the phases and the result is discussed. This study translated the requirement gathered from the interview and document analysis into several diagrams; use case diagram, activity diagram and entity relationship diagram.
A New Modulation Technique to Improve Received Power Under Turbulence Effects For Free Space Optical Communication
Authors: Rahman A K , Tom A L , Mohtadzar N.A.A , Buswig YMY , Zamhari Nurdiani , Zaidel D N A , Sahari S K , Julai N
Published: March 2020

This paper focus on new modulation technique to improve the performance of the conventional modulation that uses intensity modulation/direct detection (IM/DD) for On-Off Keying (OOK) modulation. This new modulation technique that is Dual Diffuser Modulation (DDM) can create superior modulation with able to reduce scintillation index, enhance power received and threshold signal level. The analysis result shows that the free space optical (FSO) can have good performance of power received under strong turbulence. The DDM are better performance as compare with conventional IM/DD-OOK and IM/DD-OOK with diffuser. This can help FSO system to combat with severe turbulence effect for optimum operation.
Investigation to Reduce Flux Variance Effects Using Partial Coherent Beam in Free Space Optical Communication
Authors: Rahman A K , Tom A L , Mohtadzar N A A , Buswig YMY , Zamhari Nurdiani , Sharip M R M , Sahari S K
Published: March 2020

This paper focus on the employment of partial coherent beam (PCB) in free space optical communication to reduce the flux variance effects in the system. The implementation of PCB in the free space optical system is significantly able to reduce the flux variance effect. The reduction of the flux variance effect by using PCB in free space optical communication by using Gamma-Gamma distribution is presented in this paper. The analysis result shows that the FSO system with PCB have an improved in performance compares with FSO system without PCB implemented on it as it capable to decrease the flux variance and scintillation index. This can help FSO system to encounter with severe turbulence effect for optimum operation.
Development and Performance Analysis of the Rogowski coil sensor for Arcing Fault Measurement
Authors: Nanyan A N , Isa M , Rohani M N K H , Hamid H A , Rosmi A S , Othman M. , Abdullah A. Z. , Kasa Z.C.M , Abdullah A. Nazifah
Published: March 2020

Arcing fault is an overvoltage that usually occurs in the power system network, and it is necessary to monitor this phenomenon in electrical equipment. This paper presents the Rogowski coil (RC) as an arcing fault sensor. Finite element method (FEM) software used for analysing the RC magnetic flux density with two types of RC with the different turns and size demonstrated. The sizing of RC based on the 240 mm2 cross-link polyethene (XLPE) 11 kV underground cable. The prototypes of the RC sensors were designed using Solidworks software and three-dimensional (3D) printer for fabrication purposes. The main objective of the experiment is to investigate the RC effect with high magnetic flux density by implementing in real measurement. An experimental setup for real arcing fault with various voltages (up to 15 kV) was conducted to verify the RC performance, such as sensitivity and bandwidth range. The result has shown that the bandwidth of RC 1 is higher than RC 2 in all measurement by 22.6%.
An Overview of Enhance Bandwidth Management in Cellular Network
Authors: Isam H M , Ong B L , Ahmad R B , Elshaikh M , Al-Mejibli I
Published: March 2020

cellular networks have changed our life. However, current cellular network does not have an efficient bandwidth management during congestion. Some of these techniques was used have a few drawbacks such as the performance of the handoff mechanism depends on the channel quality, QoS, bandwidth, delay and speed of the cellular node, the handoff optimizing tend to increase the ping-pong handoff rate, frequency and bandwidth. The paper indicates the promising factors of the handoff mechanisms as decrease delay, enhance speed, saving energy and control bandwidth to achieve better throughput in wireless networks as compared to predecessor networks. How limited bandwidth are segregated among nodes is discussed in details in this paper. We believe that having implemented the proposed enhanced bandwidth management, congestion in current cellular network can perform better.
Explosive Pressing Experiment and Its Challenges to Conduct it on University Level
Authors: Hilmi A.H. , Yusuf M.A.
Published: March 2020

Typical press force for hydraulic press machine for most universities are around 10 to 30 ton. For higher load, student uses Ultimate Testing Machine (UTM). Typical press force for UTM for higher learning institution is 300 ton. To obtain more press force, the specimen must be small. This is according to force equation where the smaller the surface area, the higher the force generated on it. However, the problem with small specimen is that it is difficult for researchers to do further investigations for hardness test, tensile test and microstructural analysis. Besides, there is a limit to maximum force a UTM machine can give. This paper presents steps for doing experiments using explosive pressing at university level. The explosive pressing apparatus was an improved designed by the same author. This experiment uses an amount of explosive that is place at top of the apparatus. The experiment is done underground for safety purposes. Explosive handling was done with help from authorized explosive expert. Major benefits of explosive pressing are larger samples can be pressed and the press force is very high. This paper will discuss the steps to do experiment and the challenges while doing explosive pressing using this apparatus. This paper will also show that higher pressing force can lead to finer microstructure of material being pressed.
Modelling the statistical dependence of rainfall variables using copula: A case study of Terengganu state
Authors: Fauzi M F , Rauf U F Abdul , Khan R , Jamaludin N A A
Published: March 2020

Extreme rainfall can have severe negative impacts possibly resulting in loss of life and property, hence the need for means of predicting the occurrence of extreme rainfall. One method that addresses extreme phenomena is the extreme value theory. In bivariate data, extreme value analysis can be approximated by the distribution of maximum likelihood estimation. This paper discusses the role of the copula in modeling the structure of dependencies between two rainfall variables, namely duration, and severity. Goodness-of-fit approaches are used to resolve whether or not to reject a parametric copula which then determines the best copula to utilise for the data set. In this paper the Akaike information criterion (AIC) is investigated for its ability to choose an appropriate copula model from Archimedean copula models. The analysis shows that the Frank copula is the best model to explain the dependency structure of the two variables discussed.
A review of detecting outlier in a circular regression model
Authors: Ramlee I M , Ibrahim S , Leow W Z , Yusoff M I
Published: March 2020

Circular data is very relevant and important application technique in many fields such as physical science, medical science and others. During the last few years, writers have shown a deep interest of outlier detection in the circular regression model. In this case, authors have a tendency to study and explore in detail about the outlier detection in circular regression model. This paper aims to review the outlier detection methods in circular regression model. Here, we concentrate the attention on the methods of identifying outlier in this model. These survey of circular regression models in which many interesting properties and is good enough to detect the occurrence of outlier. Through the survey may highlight the significant of methods to detect outliers in circular regressions model and provide guideline for future work to look into the research gap.
Technologies of solar tracking systems: A review
Authors: Amelia A.R. , Irwan Y.M. , Safwati I. , Leow W.Z. , Mat M.H. , Rahim Mohd Shukor Abdul
Published: March 2020

Solar energy is abundantly in nature and sustainable energy resources around the world. The main challenge with the solar field is less amount of sun energy captured by using photovoltaic (PV) systems. The great performance of the PV systems can be achieved if the panel is kept perpendicular to the direction of the radiations of sun. Hence, solar tracker system is the method to keep the optimum position of the PV panel for always perpendicular to the solar radiation. This paper aims to review on various technologies of solar tracking to determine the best PV panel orientation. The various types of technologies of solar tracking system have been discussed which includes passive solar tracker, active solar tracker and chronological tracker system. The movement degrees of solar tracking system also have been addressed which consisting single-axis solar tracking system and dual-axis solar tracking system. This paper is also overviews the tracking techniques performance, construction, performance, advantages, and disadvantages of existing solar tracking system. The limitations of solar tracking systems are also highlighted for future action improvement. Through this research studies, the most favorable solar tracking system was identified as active solar tracker with the dual axis rotation.
Voice-Based Malay Commands Recognition by Using Audio Fingerprint Method for Smart House Applications
Authors: Abu M , Amir A , Zahri N A H , Ngadiran R
Published: March 2020

Voice-based command recognition is commonly used in security systems, phones, household appliances and hardware designed for handicapped people. Most of the current research study the voice command recognition for the smart home in English. Lack of study for voice command recognition in Malay makes it challenging to apply the voice command services for the smart home in Malaysia. Also, voice recognition is a non-trivial task in natural language processing. This project is to identify the command used for smart home appliances using Malay and design the algorithm for this system. Then, the proposed algorithm will be deployed on a Raspberry Pi to see the performance of Malay command in accuracy and the suitability of the algorithm to be deployed on low cost embedded devices. Light, fan, and television had been chosen as electrical appliances to build the command. An algorithm that previously used to recognize songs, the robust quad algorithm, is used in this project for voice command recognition. The proposed method has two main processes, known as feature extraction and voice recognition. In the feature extraction process, the audio fingerprint will extract data from the command spectral peak. For voice recognition, audio fingerprint matching will be used to analyze the audio commands. The outcome of this project is when the voice command is given by the user by activate or deactivate the target home appliance. The second outcome is the background noise that affects the system is reduced by using robust quad algorithm and increase the accuracy of the system. The results of this project have shown that the proposed algorithm is suitable to be implemented on a Raspberry Pi and achieve a high recognition rate with 87%. In the presence of noise with 15 dB, the proposed algorithm can maintain the high recognition rate with 82%.
Comparative Study of Parallelism and Pipelining of RGB to HSL Colour Space Conversion Architecture on FPGA
Authors: Ehkan Phaklen , Siew Soon Voon , Zakaria Fazrul Faiz , Mohd Warip Mohd Nazri , Ilyas Mohd Zaizu
Published: March 2020

RGB colour model is a basic colour model and complements together to produce full colour range but it is unable to produce sufficient information for digital image analysis. However, HSL is capable to provide other useful information such as colour in degree, saturation of the colour and brightness of colour. In this work, RGB to HSL mathematical conversion algorithm is implemented on FPGA chip. Parallelism and pipelining capabilities of FPGA helps to speed up conversion performance. The RGB to HSL equation is implemented by using two architectures which are parallel and 7-stages pipeline architectures. The designed parallel and pipeline converters have one clock and seven clock cycle of data latency respectively. The parallel and pipeline architectures for RGB to HSL converter have been achieved rate of accuracy by hardware verification up to 99% and 98% and possessed maximum operating frequency merit of 50 MHz and 120 MHz respectively.
Indoor Navigation System for Vision Impairment People through Visible Light Communications
Authors: Rithuan Muhamad Nurnajib , Md Zain ‘Aini Syuhada , Nawawi Norizan Mohamed
Published: March 2020

Indoor navigation is opportune for everyone, and it is particularly requisite for the visually impaired. The paper proposes an indoor navigation system for the Visually Impaired to attain audio output through visible light communications. The transmission of data occurs after identifying the person who has entered the room and the technology light fidelity is used for presenting information to the user. Light fidelity technology is used by the proposed system for the wider range of transmission of data. The usage of visible light for transmitting the data encompasses a wide variety of advantages and eliminates most problems of communication caused by the electromagnetic waves outside the visible spectrum. Light fidelity technology is an evolving branch of Optical Wireless Communication and can be beneficial in coming years for indoor communication because it can afford higher data rate transmission along with the capability to utilize additional users since it uses a broader spectrum bandwidth. The main idea of our project is to create internal navigation system by using Arduino software and Arduino hardware. The transmission of data can act as transceiver, where LED and solar cell are used as the medium to transmit and receive the data.
Design of Compact UHF-RFID Tag Antenna with Meander Line Technique
Authors: Fazilah A F M , Jusoh M , Zakaria A , Sabapathy T , Ibrahim M F , Osman M N , Yaasin M N , Malhotra S , Rahim H A
Published: March 2020

In this paper, a compact UHF RFID tag antenna that can operate at Malaysia UHF RFID frequency (860 MHz – 960MHz) is proposed. The antenna with a common geometry structure without any shorting pin consists of 90degree angled line (meander line) and double T-match structure. The proposed antenna has been designed and simulated using CST Simulation software. The proposed tag antenna design shows a good performance in terms of size, gain and impedance with a dimension of 36 mm × 25 mm × 1.6 mm. The simulated gain of antenna obtained is -0.135 dB at 910 MHz with 19 MHz bandwidth.
Shared Cache Partitioning Based on Performance Gain Estimations
Authors: Mahrom N , Liebelt M J
Published: March 2020

In multiprocessor systems, dynamic cache distribution has been used to increase system performance by effectively partitioning the cache resources. However, different performance metrics used at runtime used to dynamically decide the partition sizes can give different impacts on performance, as well as varying impacts on the hardware cost of the system. In this paper, we propose an Adaptive CPI-based Cache Partitioning (ACCP) scheme to provide better utilisation of the shared cache resources among the competing applications in the system. ACCP uses performance gain estimations of the cache, without incurring significant hardware overhead. It aims to allow all applications in the system to run at approximately the same speed by accelerating the slowest application without significantly decelerating the others. We evaluated the ACCP on a quad-core system on which it achieved on average 23% reduction in miss rate, compared to an unpartitioned shared cache. ACCP also yields a similar IPC throughput improvement to a well-known UCP scheme, and better performance compared to the CPI by Muralidhara et al. Overall, the throughput of the system is improved at minimal complexity without yielding significant additional hardware cost. Hence, ACCP shows better overall performance in managing the hardware overhead compared to the UCP scheme.
Miniaturized and high gain RFID reader antenna at 13.56MHz
Authors: Saleh Y.M. , Wee F.H. , Yew B.S. , Ibrahim S. Z. , Lee Y.S.
Published: March 2020

Technology for radio frequency identification (RFID) is commonly used worldwide. RFID is a developing wireless technology which make new vital challenge. The ability to precisely read a set of RFID tags become major concern in RFID networks coverage Detailed analysis of the design based on the 13.56 MHz radio frequency was suggested to design a kind of RFID reader antenna. Previously, researchers did facing problem with the size of the antenna which was to maintain the compact size at low frequency is challenging. The proposed antenna will be designed in the shape of rectangular spiral which contribute into miniaturize of the antenna size. The antenna will be fabricated after the optimum length and width had been achieved. The goal of this project is to design a small size antenna with 55mm × 55 mm at frequency resonance of 13.56 MHz. to reduce the antenna gain on the future. We are going to design and add the metamaterial to the RFID reader antenna and combine them together and that will help to reduce the antenna gain.
Mobile Augmented Reality (AR) Marker-based for Indoor Library Navigation
Authors: Romli Rusnida , Razali Amir Firdhaus , Ghazali Nur Hafizah , Hanin Nik Adilah , Ibrahim Siti Zuraidah
Published: March 2020

This paper presents the development of Augmented Reality (AR) for smart campus urbanization using library as the environment for the demonstration of the AR prototype. The main goal of the AR development is to help users to get information and direction easily using AR based mobile application when walking inside the library. In normal circumstances, users typically walk around and explore the library area before reaching their targeted destinations. Depending on the library size and number of reading corners, exploration and walking in the library can be time consuming. Therefore, an AR technology is introduced in this paper to improve the user experience inside the library in the right direction and information instantly. This application is developed using Vuforia software to set the image marker-based and process the output into Unity3D software, Android Studio for the Main Menu interface and IBM Watson for voice recognition. The final form of the application is successfully generated from the development of Augmented Reality (AR) application for the smart campus by using a library for the demonstration of the AR prototype. A series of application tests are conducted in each corner of the library to evaluate the effectiveness of developed AR.
Effect of acids formation on the breakdown voltage properties of transformer insulating oil
Authors: Chairul Imran Sutan , Ghani Sharin Ab , Bakar Norazhar Abu , Rahim Nor Hidayah , Ab Aziz Nur Hakimah
Published: March 2020

Studies show that acids influence the electrical insulation strength of transformer insulating oil. Thus, this study was conducted to verify the influence of Low Molecular Acid (LMA) and High Molecular Acid (HMA) on the breakdown voltage of transformer insulating oil. Different weight of LMA and HMA were added into transformer insulating oil samples and then mixed using hotplate magnetic stirrer at 50°C and 750 rpm for 3 hours. Prior to the mixing process, mineral insulating oil samples were filtered, dried and its moisture content were determined according to ASTM D1533 standard test condition. After the mixing process, total acid number (TAN) and AC breakdown voltage (BdV) of the oil mixtures were measured according to standard test conditions of ASTM D974 and ASTM D1816 respectively. The obtained results verified that LMA significantly reduced the breakdown voltage of mineral insulating oil compared to HMA for acidity lower than 1 mg KOH/g.
Automated Detection of Printed Circuit Boards (PCB) Defects by Using Machine Learning in Electronic Manufacturing: Current Approaches
Authors: Zakaria S S , Amir A , Yaakob N , Nazemi S
Published: March 2020

The manufacturing of a printed circuit board in the SMT assembly line goes through multiple phases of automatic handling. To ensure the quality of the board and reduce the number of defects, inspection tasks such as solder paste inspection and automatic optical inspection are conducted. The inspection tasks are carried out at various phases of the assembly line. The paper aims to answer the questions of how machine learning technology can contribute for better PCB fault detection in the assembly line and at which parts of the assembly line this technology has been applied. The paper discusses the PCB defect detection by using machine learning and other approaches. The current research shows that PCB defect detection using machine learning are miniscule. Early detection is still unexplored and experimented in the industry.
Real-Time Drowsiness Detection System for Driver Monitoring
Authors: Arunasalam M , Yaakob N , Amir A. , Elshaikh M , Azahar N F
Published: March 2020

Nowadays, the rate of road accidents due to microsleep has been alarming. During microsleep, people might doze off without realizing it. For many decades, drowsiness detection system for vehicles was not among the major concerns though it turns out as one of imperative features that could have avoid microsleep and thus should be implemented in all vehicles in order to ensure safety of drivers and other vehicles on the road. To the best of our knowledge, enforcements on driving restriction during drowsiness state is yet to be implemented. The absence of such system in the current transportation systems expose drivers to great danger especially at night because accidents are highly likely to happen at night due to drowsy and fatigue drivers. Therefore, this project proposes a real-time drowsiness detection system for vehicles, featuring ignition lock to reduce accidents. An eye blink sensor is embedded in a wearable glasses and heart beat sensor is used to detect drowsiness level of drivers. The system also includes SMS notification system to relatives or friends with location details of the drowsy driver. This project is able to detect and react based on 3 levels of drowsiness by alerting the driver through buzzer. Ignition lock will be applied when high level of drowsiness is detected. Consequently, the vehicle will be slowed down and eventually stopped when dangerous level of drowsiness is detected as a safety precaution.
Machine Learning Algorithms for Optic Pathway Disease Diagnostics: A Review
Authors: Abu M , Zahri N A H , Amir A , Ismail I
Published: March 2020

Most of people are unaware that some of the indicators of optic pathway diseases such as stroke or tumor can be detected from the loss part of human vision, or referred as visual field defect. Ophthalmologist will manually examine the site, size and margin of the lesion from patient’s visual field points mapped by Humphrey Field Analyzer. Different site, size and margin of lesion indicates different type of defects and disease that associated with it. Therefore, an effective automated detection mechanism of multi class visual field defect is in demand to help decision making by ophthalmologist. In this paper, we review multiple techniques of supervised and unsupervised learning method for detection of optic pathway disease.
Low Cost Autonomous Robot Cleaner using Mapping Algorithm based on Internet of Things (IoT)
Authors: Ong R J , Azir K N F Ku
Published: March 2020

The objective of this study is to design and develop a low-cost Arduino autonomous robot cleaner using mapping algorithm to clean floor area of houses or offices. The idea is basically to detect any obstacles with the help of sensor and sent its output to microcontroller that will control the autonomous vacuum cleaner movement. A low-cost solution is proposed in this study by using HC-SR04 ultrasonic sensor for obstacle avoidance and control by Arduino UNO. By using an autonomous vacuum cleaner, user can turn ON the autonomous vacuum robot to clean without any help of a human operator. Wall mapping and random mapping is being applied in this study to find the effective mapping algorithm for autonomous robot cleaner. Additionally, instead of using the traditional button or switch to activate the robot, voice recognition through Google Assistant implemented in this project. Hence, this provides a more user friendly platform not only for normal user but also help visually impaired people to activate the robot.
Inclusion of Cannabis Users in Alcohol Research Samples: Screening In, Screening Out, and Implications
Authors: Venegas Alexandra , Meredith Lindsay R , Cooper Ziva D , Towns Brandon , Ray Lara A
Published: March 2020

Background

Alcohol and cannabis are frequently co-used, as 20–50% of those who drink alcohol report co-using cannabis. This study is based on the argument that alcohol researchers should enroll cannabis users in human laboratory studies of alcohol use disorder (AUD) to strengthen generalizability. This study examines how heavy drinking cannabis users differ from non-cannabis using heavy drinkers.

Methods

In a community sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users were identified through: (a) self-reported cannabis use in the past 6 months and (b) positive urine toxicology test for tetrahydrocannabinol (THC). Cannabis users, identified as described previously, were compared with non-cannabis users on demographic and clinical characteristics.

Results

Those who endorsed cannabis use in the past 6 months reported more binge drinking days. Participants who tested positive for THC had higher Alcohol Use Disorder Identification Test scores and more binge drinking days. Younger age and being a tobacco smoker were associated with an increased likelihood of cannabis use in the past 6 months, whereas male gender and being a tobacco use were associated with a greater likelihood of testing positive for THC. Individuals with cannabis use disorder (CUD) endorsed more depression and anxiety and had higher AUD symptom counts than cannabis users without CUD.

Conclusions

The inclusion of cannabis users in AUD samples allows for increased clinical severity. Excluding cannabis users from AUD studies may limit representativeness and expend unnecessary study resources. Lastly, tobacco use may explain a large portion of the effects of cannabis use on sample characteristics.

Short Summary

Alcohol and cannabis are frequently co-used substances. In a sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users reported higher alcohol use and higher likelihood of tobacco use than non-cannabis users. Including cannabis users in alcohol research studies will improve representativeness and likely increase clinical severity.
Systematics, biogeography, and diversification of Scytalopus tapaculos (Rhinocryptidae), an enigmatic radiation of Neotropical montane birds
Authors: Cadena Carlos Daniel , Cuervo Andrés M , Céspedes Laura N , Bravo Gustavo A , Krabbe Niels , Schulenberg Thomas S , Derryberry Graham E , Silveira Luis Fabio , Derryberry Elizabeth P , Brumfield Robb T , Fjeldså Jon
Published: March 2020

We studied the phylogeny, biogeography, and diversification of suboscine passerines in the genus Scytalopus (Rhinocryptidae), a widespread, species-rich, and taxonomically challenging group of Neotropical birds. We analyzed nuclear (exons, regions flanking ultraconserved elements) and mitochondrial (ND2) DNA sequence data for a taxonomically and geographically comprehensive sample of specimens collected from Costa Rica to Patagonia and Brazil. We found that Scytalopus is a monophyletic group sister to Eugralla and consists of 3 main clades roughly distributed in (1) the Southern Andes, (2) eastern Brazil, and (3) the Tropical Andes and Central America. The clades from the Southern Andes and eastern Brazil are sister to each other. Despite their confusing uniformity in plumage coloration, body shape, and overall appearance, rates of species accumulation through time in Scytalopus since the origin of the clade in the Late Miocene are unusually high compared with those of other birds, suggesting rapid non-adaptive diversification in the group. We attribute this to their limited dispersal abilities making them speciation-prone and their occurrence in a complex landscape with numerous barriers promoting allopatric differentiation. Divergence times among species and downturns in species accumulation rates in recent times suggest that most speciation events in Scytalopus predate climatic oscillations of the Pleistocene. Our analyses identified various cases of strong genetic structure within species and lack of monophyly of taxa, flagging populations which likely merit additional study to clarify their taxonomic status. In particular, detailed analyses of species limits are due in S. parvirostris, S. latrans, S. speluncae, the S. atratus complex, and the Southern Andes clade.
Epidemiological and Clinical Predictors of COVID-19
Authors: Sun Yinxiaohe , Koh Vanessa , Marimuthu Kalisvar , Ng Oon Tek , Young Barnaby , Vasoo Shawn , Chan Monica , Lee Vernon J M , De Partha P , Barkham Timothy , Lin Raymond T P , Cook Alex R , Leo Yee Sin ,   National Centre for Infectious Diseases COVID-19 Outbreak Research Team, Lian Lim Poh , Ang Brenda , Chuan Lee Cheng , Lye David Chien Boon , Ling Li Min , Lee Lawrence Soon-U , Sadarangani Sapna , Seong Wong Chen , Lee Tau Hong , Junhao Lin Ray , Chia Po Ying , Sadasiv Mucheli Sharavan , Ng Deborah Hee Ling , Choy Chiaw Yee , Yeo Tsin Wen , Tan Glorijoy Shi En , Chan Yu Kit , Tay Jun Yang , Lee Pei Hua , Ong Sean Wei Xiang , Sutjipto Stephanie , Wee Ian Liang En , Frederico Dimatatac , Go Chi Jong , Isais Florante Santo
Published: March 2020

Background

Rapid identification of COVID-19 cases, which is crucial to outbreak containment efforts, is challenging due to the lack of pathognomonic symptoms and in settings with limited capacity for specialized nucleic acid–based reverse transcription polymerase chain reaction (PCR) testing.

Methods

This retrospective case-control study involves subjects (7–98 years) presenting at the designated national outbreak screening center and tertiary care hospital in Singapore for SARS-CoV-2 testing from 26 January to 16 February 2020. COVID-19 status was confirmed by PCR testing of sputum, nasopharyngeal swabs, or throat swabs. Demographic, clinical, laboratory, and exposure-risk variables ascertainable at presentation were analyzed to develop an algorithm for estimating the risk of COVID-19. Model development used Akaike’s information criterion in a stepwise fashion to build logistic regression models, which were then translated into prediction scores. Performance was measured using receiver operating characteristic curves, adjusting for overconfidence using leave-one-out cross-validation.

Results

The study population included 788 subjects, of whom 54 (6.9%) were SARS-CoV-2 positive and 734 (93.1%) were SARS-CoV-2 negative. The median age was 34 years, and 407 (51.7%) were female. Using leave-one-out cross-validation, all the models incorporating clinical tests (models 1, 2, and 3) performed well with areas under the receiver operating characteristic curve (AUCs) of 0.91, 0.88, and 0.88, respectively. In comparison, model 4 had an AUC of 0.65.

Conclusions

Rapidly ascertainable clinical and laboratory data could identify individuals at high risk of COVID-19 and enable prioritization of PCR testing and containment efforts. Basic laboratory test results were crucial to prediction models.
Fears of Falling Short versus Anxieties of Decline: Explaining Russia and China’s Approach to Status-Seeking
Authors: Krickovic Andrej , Zhang Chang
Published: March 2020

Although recent scholarship has advanced our understanding of status, little attention has been paid to the factors that shape states’ status-seeking behaviour. Consequently, existing theories are unable to explain why Russia has been more aggressive and confrontational in its status-seeking than China. What is missing is a detailed examination of the ways in which status-seekers’ power trajectories affect their status-seeking behaviour. Whether a status-seeker is rising or in decline shapes its propensity to take risks in pursuit of status, its calculations regarding the utility of attaining more status, and its ability to use non-confrontational and non-aggressive status-seeking strategies to induce other states to accord it higher status. Declining powers, such as Russia, engage in aggressive status-seeking to avoid imminent status losses. Decliners need to initiate confrontations with other states to compel them to recognise their status. Risers, such as China, are more cautious and restrained. Recognising that aggressive status-seeking can jeopardise imminent gains, they are conscious of the costs that accompany elevated status. Their admirable successes and growing power, moreover, make other states all the more willing to accord them higher status. Risers, therefore, can enhance their status without resorting to aggressive or confrontational methods.
Systematic Review of Development and Content Validity of Patient-reported Outcome Measures in Inflammatory Bowel Disease: Do We Measure What We Measure?
Authors: van Andel Emma M , Koopmann Brechtje D M , Crouwel Femke , Noomen Casper G , de Boer Nanne K H , van Asseldonk Dirk P , Mokkink Lidwine B
Published: March 2020

Background and Aims

Patient-reported outcome measures are increasingly important in daily care and research in inflammatory bowel disease [IBD]. This study provides an overview of the content and content validity of IBD-specific patient-reported outcome measures on three selected constructs.

Methods

Databases were searched up to May 2019 for development and/or content validity studies on IBD-specific self-report measures on health-related quality of life, disability, and self-report disease activity in adults. Evidence was synthesised on content validity in three aspects: relevance, comprehensiveness, and comprehensibility following the COnsensus-based Standards for the selection of health Measurement INstruments methodology. Questionnaire items were organised in themes to provide an overview of important aspects of these constructs.

Results

For 14/44 instruments, 25 content validity studies were identified and 25/44 measures had sufficient content validity, the strongest evidence being of moderate quality, though most evidence is of low or very low quality. The Crohn’s Life Impact Questionnaire and IBD questionnaire-32 on quality of life, the IBD-Control on disease activity, and the IBD Disability Index Self-Report and its 8-item version on disability, have the strongest evidence of sufficient relevance, comprehensiveness, and comprehensibility, ranging from moderate to very low quality. A fair number of recurring items themes, possibly important for the selected constructs, was identified.

Conclusions

The body of evidence for content validity of IBD-specific health-related quality of life, self-report disease activity, and disability self-report measures is limited. More content validity studies should be performed after reaching consensus on the constructs of interest for IBD, and studies should involve patients.
Relapse 1 week after bracket removal: a 3D superimpositional analysis
Authors: Papagiannis Alexandros , Koletsi Despina , Halazonetis Demetrios J , Sifakakis Iosif
Published: March 2020

Objectives

To measure tooth movement 1 week post-treatment and assess potential correlation with changes invoked during treatment.

Subjects and methods

Thirty-eight patients were recruited (19 males, 19 females). Polyvinyl siloxane impressions were taken after bracket debonding (T1) and 1 week later (T2) and digitally scanned. During this period no retention was used. The digital casts were superimposed on structures of the hard palate. Translation and rotation of the first molars, canines, and central incisors were recorded. Additionally, movement of these teeth was assessed from the beginning (T0) until the end of treatment (T1). The correlation between the post-treatment relapse (T1–T2) and tooth movement during treatment (T0–T1) was investigated via the Spearman correlation coefficient.

Results

Relapse was detected and reflected changes in tooth position during treatment. For the first molars (right, left) the correlation between treatment and post-treatment tooth movement was evident in the transverse direction (r = −0.38, P = 0.020; r = −0.32, P = 0.052), tipping (r = −0.40, P = 0.015; r = −0.34, P = 0.034) and the antero-posterior direction (r = −0.31, P = 0.061; r = −0.36, P = 0.027); for the canines (right and left), as rotation around their long axis (r = −0.55, P = 0.003; r = −0.58, P = 0.002); for central incisors (right and left) in the antero-posterior direction (r = −0.55, P = 0.000; r = −0.48, P = 0.03), transverse direction (r = −0.43, P = 0.07; r = −0.32, P = 0.047), and rotation around their long axis (r = −0.53, P = 0.001; r = −0.28, P = 0.089).

Conclusions

Post-treatment changes in tooth position were mostly related to tooth movement during treatment. The reported correlations may help clinicians predict short-term relapse, evaluate long-term retention need, and design individualized retention schemes.
Staying close: short local dispersal distances on a managed forest of two Patagonian Nothofagus species
Authors: Sola Georgina , El Mujtar Verónica , Gallo Leonardo , Vendramin Giovanni G , Marchelli Paula
Published: March 2020

Understanding the impact of management on the dispersal potential of forest tree species is pivotal in the context of global change, given the implications of gene flow on species evolution. We aimed to determine the effect of logging on gene flow distances in two Nothofagus species from temperate Patagonian forests having high ecological relevance and wood quality. Therefore, a total of 778 individuals (mature trees and saplings) of Nothofagus alpina and N. obliqua, from a single plot managed 20 years ago (2.85 hectares), were mapped and genotyped at polymorphic nuclear microsatellite loci. Historical estimates of gene dispersal distance (based on fine-scale spatial genetic structure) and contemporary estimates of seed and pollen dispersal (based on spatially explicit mating models) were obtained. The results indicated restricted gene flow (gene distance ≤ 45 m, both pollen and seed), no selfing and significant seed and pollen immigration from trees located outside the studied plot but in the close surrounding area. The size of trees (diameter at breast height and height) was significantly associated with female and/or male fertility. The significant fine-scale spatial genetic structure was consistent with the restricted seed and pollen dispersal. Moreover, both estimates of gene dispersal (historical and contemporary) gave congruent results. This suggests that the recent history of logging within the study area has not significantly influenced on patterns of gene flow, which can be explained by the silviculture applied to the stand. The residual tree density maintained species composition, and the homogeneous spatial distribution of trees allowed the maintenance of gene dispersal. The short dispersal distance estimated for these two species has several implications both for understanding the evolution of the species and for defining management, conservation and restoration actions. Future replication of this study in other Nothofagus Patagonian forests would be helpful to validate our conclusions.
Impact of ventilation design on the precooling effectiveness of horticultural produce—a review
Authors: Cao Yuhui , Gong Ya-Fang , Zhang Xin-Rong
Published: March 2020

Optimizing the ventilation design of packaging system is of crucial importance for improving the efficiency of the forced-air precooling process to maintain the quality of horticultural produce and extend the shelf life in food cold chain. Many efforts had been devoted to the study about the impact of ventilation design on airflow and temperature distribution inside ventilated packages. This paper reviews relevant research methods, commonly used quantities for the measurement of precooling effectiveness, attractive design parameters, and their impact on precooling effectiveness. These allow us to know exactly the characteristic and deficiency of each research method, identify dominant design parameters, and seek a promising way for the future improvement of the ventilated packaging system.
The Biomechanics of Multi-articular Muscle–Tendon Systems in Snakes
Authors: Astley Henry C
Published: March 2020

Synopsis

The geometry of the musculoskeletal system, such as moment arms and linkages, determines the link between muscular functions and external mechanical results, but as the geometry becomes more complex, this link becomes less clear. The musculoskeletal system of snakes is extremely complex, with several muscles that span dozens of vertebrae, ranging from 10 to 45 vertebrae in the snake semispinalis-spinalis muscle (a dorsiflexor). Furthermore, this span correlates with habitat in Caenophidians, with burrowing and aquatic species showing shorter spans while arboreal species show longer spans. Similar multi-articular spans are present in the prehensile tails of primates, the necks of birds, and our own digits. However, no previous analysis has adequately explained the mechanical consequences of these multi-articular spans. This paper uses techniques from the analysis of static systems in engineering to analyze the consequences of multiarticular muscle configurations in cantilevered gap bridging and compares these outcomes to a hypothetical mono-articular system. Multi-articular muscle spans dramatically reduce the forces needed in each muscle, but the consequent partitioning of muscle cross-sectional area between numerous muscles results in a small net performance loss. However, when a substantial fraction of this span is tendinous, performance increases dramatically. Similarly, metabolic cost is increased for purely muscular multi-articular spans, but decreases rapidly with increasing tendon ratio. However, highly tendinous spans require increased muscle strain to achieve the same motion, while purely muscular systems are unaffected. These results correspond well with comparative data from snakes and offer the potential to dramatically improve the mechanics of biomimetic snake robots.