The Effects of Principals’ Digital Leadership on Teachers’ Digital Teaching during the Covid-19 Pandemic in Malaysia

Education involving digital technology is the latest transformation of the education system, especially during the occurrence of the COVID-19 pandemic. The Malaysian Ministry of Education (MOE) has taken the initiative to spearhead efforts to develop the skills and potential of students in the use of digital technology. The main purpose of this study was to identify the level of digital leadership displayed by principals, the level of teachers' digital teaching practices and the elements of principals' digital leadership that predict the level of teachers' digital teaching. About 400 secondary school teachers in Hulu Langat District, Selangor were involved in this study. The findings of this study show that the level of digital leadership displayed by principals and teachers’ digital teaching practice are both at a high level. However, the positive correlation between the two is moderate. Multiple regression found that only digital citizenship is a strong predictor of teachers' digital teaching. The findings show that the ability to plan and organize digital leadership programs is important and can help improve students' academic performance, despite the COVID-19 pandemic crisis

Effect of vibration after filling on mechanical reliability in thin wall investment casting with fillability filling regime—part 1

A vibration technique is used in this study to explore the effect of low frequency vibration on the mechanical reliability of Al-7Si-Mg castings. The quality of castings is related to the number and the size of porosity and oxide film in thin wall investment casting. The quality of each method of casting (casting with and without vibration) was assessed by the density of the defects within the thin strips. Weibull distribution function is used to analyze the tensile strength data. The Weibull modulus is applied as a criterion to assess the mechanical reliability to identify the optimized casting condition. The results show that the effect of the vibration on the mechanical reliability is markedly dependent on acceleration of vibration, and the Weibull modulus is in the range of 12 to 12.7 when the acceleration is in range of 0 to 1 g; however, in more than 1 g, the range is 30–35

The relation between calcaneus stiffness index as a measure of bone density and body mass index in an Egyptian cohort

Background: Obesity and osteoporosis are two conditions that are associated with morbidity and mortality; there is contradictory evidence regarding this association. Purpose: The aim of the current study was to explore further the association between obesity and calcaneus stiffness index (CSI), as a measure of bone density, in a community-based cross-sectional study in an Egyptian population. Methods: A cross-sectional study was conducted among active subjects, aged ≥20 years old, over one year. CSI was measured by Quantitative ultrasound (QUS), in addition; QUS T-score and Z-score of the non-dominant heel scan were recorded. Results: Two hundred and eighty participants were recruited; 7 subjects were excluded because of Z score more than −2, mean age was 61 (± 11.9) years, and mean BMI was 29.7 (±5.6). Female participants were 77.7%, with mean of age 60.3 (± 11.6); and age range 20–82 years. Male participants were 22.3%, with mean of age 63.6 (± 12.7); and age range 30–80 years. Older subjects (>55 years) had significantly lower CSI and worse T-score than the younger subjects (P < 0.001 for both). In the younger age group, BMI was not significantly associated with CSI, even after adjustment for gender (P= 0.52). However, in the older age group, BMI was significantly associated with stiffness index (P= 0.049, O.R.= 1.73), even after adjustment for gender (P= 0.041, O.R.= 1.7). Conclusion: Compared to young subjects, older subjects (≥55 years) had significantly lower bone strength as measured by CSI, and their BMI was significantly positively associated with bone density. In younger people (<55 years), BMI was not associated with bone strength

Target Localization in MIMO OFDM Radars Adopting Adaptive Power Allocation among Selected Sub-Carriers

Multiple-input multiple-output (MIMO) radar has been introduced to enhance the performance of classical radar systems. Nevertheless, radar cross sections (RCS) fluctuations remains a known problem in radars. Target localization using narrowband signal produces reduced accuracy due to RCS fluctuations. One of the solution to this problem is utilization of frequency diversity of wideband signal. This paper presents target localization in MIMO radars using an adaptive orthogonal frequency division multiplexing (OFDM) waveform for effective frequency diversity utilization. Each transmitting antenna transmits an OFDM signal in different time slots and received by the each receiving antenna in the receiver array. A joint direction-of-departure (DOD) and direction-of-arrival (DOA) estimation scheme is applied to each of the OFDM sub-carrier using two-way multiple signal classification (MUSIC) algorithm. The estimation results at each sub-carrier are combined based on majority decision using angle histogram (non-parametric approach) to formulate the final wideband angle estimation. In addition, an adaptive power allocation among the sub-carriers is implemented, where the system evaluates the signal quality at each sub-carrier and consequently formulates a feedback to the MIMO transmitting side. The following transmission will comprise of OFDM waveform that focuses the transmit power at selected sub-carriers only. The sub-carrier selection is based on singular values obtained from singular value decomposition operation at each of the sub-carrier. The performance of the proposed scheme is evaluated through numerical simulations as well as validation by experiments in a radio anechoic chamber. It was demonstrated that the usage of larger number of sub-carriers improves the angle estimation accuracy

Multi-Layer Perceptron (MLP)-Based Nonlinear Auto-Regressive with Exogenous Inputs (NARX) Stock Forecasting Model

The prediction of stocks in the stock market is important in investment as it would help the investor to time buy and sell transactions to maximize profits. In this paper, a Multi-Layer Perceptron (MLP)-based Nonlinear Auto-Regressive with Exogenous Inputs (NARX) model was used to predict the prices of the Apple Inc. weekly stock prices over a time horizon of 1995 to 2013. The NARX model belongs is a system identification model that constructs a mathematical model from the dynamic input/output readings of the system, and predicts the future behaviour of the system based on the constructed mathematical model. The One Step Ahead (OSA) and correlation tests were used to test validate the model. Results demonstrate the predictive ability of the model while producing Gaussian residuals (indicating the validity of the model)

Dual-Band Bandpass Filter with Dumbbell Shaped Defective Ground Structure

A dumbbell shaped defective ground structure (DGS) is implemented to improve the performance of an existing dual-band bandpass filter topology. The filter design is based on parallel-coupled lines connected to matched transmission lines. Various positions and dimensions of dumbbell DGSs are implemented and their effects on the filter performance are investigated. It is found that the utilisation of dumbbell shaped DGSs in this topology improve the steepness of the responses for the first and second passbands with centre frequencies of 1.365 and 2.932 GHz respectively. The optimised dimensions of the DGS are 5 x 5 mm2 for both its rectangular slots connected by a 0.5 mm narrow slot width. The optimised positions of the DGSs are located at the centre and the edges of the parallel-coupled lines. The simulated and measured results of the filter are analysed and discussed in this paper

A review on quality enhancement of oil palm trunk waste by resin impregnation: future materials

Oil palm trunk (OPT) is a solid waste obtained in large quantities after the felling of oil palm trees and is available year-round. Scientists and industrialists face difficulties in utilizing these solid wastes for different applications due to great variations in their physical and mechanical properties. Because OPT consists of lignocellulosic materials, its cellulosic material is utilized in the production of panel products such as particleboard, medium density fibreboard, mineral-bonded particleboard, block board, and cement board. In order to control the OPT waste, it is essential to consider its alternative utilization inside buildings as lightweight construction materials and furniture. The impregnation of different resins in wood and non-wood materials can improve the quality of the OPT, making it possible to utilize OPT as raw materials for different applications. The enhanced properties and good appearance of impregnated OPT have found use in high-grade furniture and housing materials. In order to further evaluate its potential, this review has been compiled for the detailed study of various properties, characteristics, and applications of OPT

Multidimensionality of visual social media marketing and its impact on customer purchase intention on the real estate market

The modern real estate industry, including real estate market in Jordan, is highly competitive and challenging. This descriptive study aims to examine the effect of visual social media marketing (VSMM) on customer purchase intentions of Jordanian real estate companies. The paper used electronic word-of-mouth (e-WOM) as a mediator and reliability as a moderator of the relationship between e-WOM and customers’ purchase intention. A conceptual model comprised VSMM dimensions (informative content, entertainment content, and remunerative content), which affect the purchase intention of customers, mediated by thee WOM construct. The construct of reliability moderated the link between e-WOM and purchase intention. Questionnaires were distributed through Google Forms to respondents selected by convenience sampling; as a result, 250 responses were received. PLS-SEM was used to analyze the data and test the hypotheses. The results confirmed a significant impact of VSMM and e-WOM on purchase intentions. In addition, the study found that e-WOM mediates the relationship between VSMM and purchase intention, and reliability moderates the link between e-WOM and purchase intention. The results can help Jordanian real estate companies employ VSMM to increase their customers’ purchase intentions

Biventricular pacemaker therapy improves exercise capacity in patients with non‐obstructive hypertrophic cardiomyopathy via augmented diastolic filling on exercise

Aims Treatment options for patients with non‐obstructive hypertrophic cardiomyopathy (HCM) are limited. We sought to determine whether biventricular (BiV) pacing improves exercise capacity in HCM patients, and whether this is via augmented diastolic filling. Methods and results Thirty‐one patients with symptomatic non‐obstructive HCM were enrolled. Following device implantation, patients underwent detailed assessment of exercise diastolic filling using radionuclide ventriculography in BiV and sham pacing modes. Patients then entered an 8‐month crossover study of BiV and sham pacing in random order, to assess the effect on exercise capacity [peak oxygen consumption (VO2)]. Patients were grouped on pre‐specified analysis according to whether left ventricular end‐diastolic volume increased (+LVEDV) or was unchanged/decreased (–LVEDV) with exercise at baseline. Twenty‐nine patients (20 male, mean age 55 years) completed the study. There were 14 +LVEDV patients and 15 –LVEDV patients. Baseline peak VO2 was lower in –LVEDV patients vs. +LVEDV patients (16.2 ± 0.9 vs. 19.9 ± 1.1 mL/kg/min, P = 0.04). BiV pacing significantly increased exercise ΔLVEDV (P = 0.004) and Δstroke volume (P = 0.008) in –LVEDV patients, but not in +LVEDV patients. Left ventricular ejection fraction and end‐systolic elastance did not increase with BiV pacing in either group. This translated into significantly greater improvements in exercise capacity (peak VO2 + 1.4 mL/kg/min, P = 0.03) and quality of life scores (P = 0.02) in –LVEDV patients during the crossover study. There was no effect on left ventricular mechanical dyssynchrony in either group. Conclusion Symptomatic patients with non‐obstructive HCM may benefit from BiV pacing via augmentation of diastolic filling on exercise rather than contractile improvement. This may be due to relief of diastolic ventricular interaction. Clinical Trial Registration: ClinicalTrials.gov NCT00504647

Characterisation of cholinesterase from kidney tissue of Asian seabass (Lates calcarifer) and its inhibition in presence of metal ions

Aim: The chdinesterase (ChE) based inhibition studies from fish were investigated and presented here emerged to be one of thegreat potential biomarkersfor heavy metals monitoring. Methodology: In this study, the capability of ChE extracted from the kidney of Lates calcarifer was assessed for of metal. ChE was purified through ammonium sulphate precipitation and ion exchange chromatography. Results: The piffled enzyme gave 12 fold purification with the recovery of 12.17% with specific activity of 2.889 U mgJ. The Michaelis-Menten constant (K) and V,^ value obtained was 0.1426 mM and 0.0217 pmol irin'mg∗1, respectively. The enzyme has the ability to hydrolyse acetytthiocholine iodde (ATC) at a faster rate compared to other two synthetic su bstra tes , propionylthiocholine iodide (PTC) and butyrylthiocholine iodide (BTC). ChE gave highest activity at 20- 30°C in Tris-HO buffer pH 8.0. The results showed that cholinesterase from L. calcarifer kidney was very sensitive to sensitive to copper and lead after being tested argentum, arsenic, cadmium, chromium, copper, cobalt, mercury, nickel, lead and zinc. Interpretation: The effect of heavy metals studied on the activity of ChE differed from each other. The result of the study can be used as a tool for futher developing a biomarker for the detection of heavy metals in aquatic ecosystems. In addition, the information can also be used for designing a kit, that would give a rapid and accurate result