GARCH Diagnosis with Portmanteau Bicorrelation Test: An Application on the Malaysia's Stock Market

This study employed the Hinich portmanteau bicorrelation test (Hinich and Patterson, 1995; Hinich, 1996) as a diagnostic tool to determine the adequacy of the GARCH model in describing the returns generating process of Malaysia’s stock market, specifically the Kuala Lumpur Stock Exchange Composite Index (KLSE CI). The bicorrelation results demonstrated that, while GARCH model is commonly applied to financial time series, this model cannot provide an adequate characterization for the underlying process of KLSE CI. Further investigation using the windowed test procedure revealed that this was due to the presence of episodic non- stationarity in the data, which could not be captured by any kind of ARCH or GARCH model, even after modifications to the specifications of the GARCH model. Thus, this study points to the need to continue the search for a parsimonious and congruent model capable of capturing the episodic features presence in the returns series of KLSE CI.GARCH; Non-linearity; Non-stationarity; Data generating process; Bicorrelation; Malaysian stock market.

Neural network transient stability assessment of a single-machine system under asymmetrical fault conditions

The authors propose a neural network approach for transient stability assessment and for critical fault clearing time estimation for a single-machine system under asymmetrical fault conditions. They describe the back-propagation neural network configurations adopted and detail the different stages in the training process of the neural networks. Results obtained by applying the neural network approach to a single-machine system show that fast and accurate assessment of transient stability boundaries can be achieved but the approach requires further improvement for use in the estimation of critical fault clearing times

Effects of rare earth nanoparticles (M = Sm2O3, Ho2O3, Nd2O3) addition on the microstructure and superconducting transition of Bi1.6Pb0.4Sr2Ca2Cu3O10+δ ceramics

The effect of rare earth nanoparticles, M=Sm2O3, Nd2O3 and Ho2O3 added to (Bi1.6Pb0.4Sr2Ca2Cu3O10+δ)1-x(M)x, where x = 0.00 - 0.05, superconductor were studied by X-ray diffraction technique (XRD), resistivity (R), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The volume fraction of high-Tc phase, Bi-2223, decreased from 84% for pure sample to 48, 30 and 23% at x = 0.05 for Sm2O3, Ho2O3 and Nd2O3 additions, respectively. The critical temperature Tc(R=0) that is 102 K for the pure sample decreased to 78, 73 and 69 K at x = 0.05 for samples with Sm2O3, Nd2O3 and Ho2O3 nanoparticles additions, respectively. The additions of rare earth nanoparticles decreased the grain size and increased the random orientation of the grains. The results showed that the phases’ formations, variations of lattice parameters and electrical properties are sensitive to the size of nanoparticles and magnetic properties of its ions

Fishes of the Eastern Johor Strait

© National University of Singapore. We record the presence of 435 fish species from the Eastern Johor Strait based on our fieldwork, a review of the existing literature, and an examination of photographs and museum specimens. Four species are recorded for the first time from the waters of Singapore: Pseudorhombus elevatus (Paralichthyidae), Heteromycteris hartzfeldii (Soleidae), Nuchequula manusella (Leiognathidae) and Johnius carouna (Sciaenidae)

Phase evolution and crystallite size of La-substituted YIG at differentcalcination temperatures.

Yttrium iron garnet (YIG) substituted lanthanum ions (La3+) Y3-xLaxFe5O12 were synthesized at different temperatures. The effect of calcination temperature on crystalline structures was investigated by using X-ray diffraction (XRD). The results show that the crystallization of the samples La-substituted YIG x=0.0 and x=0.5 is more completed when the calcination temperature increases. However, Fe2O3 phase was formed in the sample with La substitution of x=1.0 when the temperature increases. The sizes of substituted YIG particles calculated from Scherrer equation were ranged from 29 to 71 nm and it was found increased with the increasing of calcination temperature

Is intrinsic lumbar spine shape associated with lumbar disc degeneration? An exploratory study

Acknowledgements Thank you to Lesley Honeyfield (Lead Research Radiographer, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London) for assisting with imaging optimisation and the acquisition of MR images and to all participants in this study. We also thank the University of Aberdeen Data Management Team for programming support for ‘Shape’ software. Funding JD would like to acknowledge the support of Versus Arthritis (Clinical Doctoral Fellowship award, grant number 20172) and the UKSSB and Society for Back Pain Research (Travel Fellowship award) for funding this research. Funders did not have a role in the design of the study, analysis or interpretation of the data.Peer reviewedPublisher PD

Resuscitation and quantification of stressed Escherichia coli K12 NCTC8797 in water samples

The aim of this study was to investigate the impact on numbers of using different media for the enumeration of Escherichia coli subjected to stress, and to evaluate the use of different resuscitation methods on bacterial numbers. E. coli was subjected to heat stress by exposure to 55 °C for 1 h or to light-induced oxidative stress by exposure to artificial light for up to 8 h in the presence of methylene blue. In both cases, the bacterial counts on selective media were below the limits of detection whereas on non-selective media colonies were still produced. After resuscitation in non-selective media, using a multi-well MPN resuscitation method or resuscitation on membrane filters, the bacterial counts on selective media matched those on non-selective media. Heat and light stress can affect the ability of E. coli to grow on selective media essential for the enumeration as indicator bacteria. A resuscitation method is essential for the recovery of these stressed bacteria in order to avoid underestimation of indicator bacteria numbers in water. There was no difference in resuscitation efficiency using the membrane filter and multi-well MPN methods. This study emphasises the need to use a resuscitation method if the numbers of indicator bacteria in water samples are not to be underestimated. False-negative results in the analysis of drinking water or natural bathing waters could have profound health effects

Comparative genome analysis of multiple vancomycin-resistant Enterococcus faecium isolated from two fatal cases

Enterococcus faecium is both a commensal of the human intestinal tract and an opportunistic pathogen. The increasing incidence of enterococcal infections is mainly due to the ability of this organism to develop resistance to multiple antibiotics, including vancomycin. The aim of this study was to perform comparative genome analyses on four vancomycin-resistant Enterococcus faecium (VREfm) strains isolated from two fatal cases in a tertiary hospital in Malaysia. Two sequence types, ST80 and ST203, were identified which belong to the clinically important clonal complex (CC) 17. This is the first report on the emergence of ST80 strains in Malaysia. Three of the studied strains (VREr5, VREr6, VREr7) were each isolated from different body sites of a single patient (patient Y) and had different PFGE patterns. While VREr6 and VREr7 were phenotypically and genotypically similar, the initial isolate, VREr5, was found to be more similar to VRE2 isolated from another patient (patient X), in terms of the genome contents, sequence types and phylogenomic relationship. Both the clinical records and genome sequence data suggested that patient Y was infected by multiple strains from different clones and the strain that infected patient Y could have derived from the same clone from patient X. These multidrug resistant strains harbored a number of virulence genes such as the epa locus and pilus-associated genes which could enhance their persistence. Apart from that, a homolog of E. faecalis bee locus was identified in VREr5 which might be involved in biofilm formation. Overall, our comparative genomic analyses had provided insight into the genetic relatedness, as well as the virulence potential, of the four clinical strains

Transnational teaching teams: Professional development for quality enhancement of teaching and learning-Final Report

The Transnational Teaching Teams: professional development for quality enhancement of learning and teaching project was a two-year Office for Learning and Teaching (OLT)-funded project that targeted professional-practice development for transnational teaching teams to enhance quality learning and teaching in transnational education programs. Five partner universities were involved: the University of Wollongong (lead), INTI International University and Colleges (Malaysia), RMIT International University (Vietnam), RMIT University and La Trobe University

Effect of Grain Boundary Character Distribution on the Impact Toughness of 410NiMo Weld Metal

Grain boundary character distributions in 410NiMo weld metal were studied in the as-welded, first-stage, and second-stage postweld heat treatment (PWHT) conditions, and these were correlated with the Charpy-V impact toughness values of the material. The high impact toughness values in the weld metal in the as-welded and first-stage PWHT conditions compared to that in the second-stage condition are attributed to the higher fraction of low-energy I pound boundaries. A higher volume fraction of retained austenite and coarser martensite after second-stage PWHT accompanied by the formation of the ideal cube component in the 2-hour heat-treated specimen led to a reduction in the toughness value. A subsequent increase in the PWHT duration at 873 K (600 A degrees C) enhanced the formation of {111}aOE (c) 112 >, which impedes the adverse effect of the cubic component, resulting in an increase in the impact toughness. In addition to this, grain refinement during 4-hour PWHT in the second stage also increased the toughness of the weld metal