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Fulltext Assessing the Efficacy of Adjustable Moving Averages Using ASEAN-5 Currencies

Chan Phooi M'ng J, Zainudin R

PLoS One, 2016;11(8):e0160931.
PMID: 27574972 DOI: 10.1371/journal.pone.0160931

The objective of this research is to examine the trends in the exchange rate markets of the ASEAN-5 countries (Indonesia (IDR), Malaysia (MYR), the Philippines (PHP), Singapore (SGD), and Thailand (THB)) through the application of dynamic moving average trading systems. This research offers evidence of the usefulness of the time-varying volatility technical analysis indicator, Adjustable Moving Average (AMA') in deciphering trends in these ASEAN-5 exchange rate markets. This time-varying volatility factor, referred to as the Efficacy Ratio in this paper, is embedded in AMA'. The Efficacy Ratio adjusts the AMA' to the prevailing market conditions by avoiding whipsaws (losses due, in part, to acting on wrong trading signals, which generally occur when there is no general direction in the market) in range trading and by entering early into new trends in trend trading. The efficacy of AMA' is assessed against other popular moving-average rules. Based on the January 2005 to December 2014 dataset, our findings show that the moving averages and AMA' are superior to the passive buy-and-hold strategy. Specifically, AMA' outperforms the other models for the United States Dollar against PHP (USD/PHP) and USD/THB currency pairs. The results show that different length moving averages perform better in different periods for the five currencies. This is consistent with our hypothesis that a dynamic adjustable technical indicator is needed to cater for different periods in different markets.
A new species of Leptolalax from Sarawak, Western Borneo (Anura: Megophryidae)

Matsui M, Zainudin R, Nishikawa K

Zoolog Sci, 2014 Nov;31(11):773-9.
PMID: 25366161 DOI: 10.2108/zs140137

A new megophryid species is described from southwestern Sarawak, Malaysian Borneo. In appearance, Leptolalax marmoratus sp. nov. is most similar to L. hamidi also from southwestern Sarawak, but differs from it by mtDNA sequence, larger body size, and higher dominant frequency of advertisement call. The assumption that more than one species of Leptolalax coexist at one locality in Borneo is supported. The finding of the new species raises the species number of Leptolalax known from Borneo to nine, and the island is thought to be one of the diversification centers of the genus.
Gastrointestinal parasites of zoonotic importance observed in the wild, urban, and captive populations of non-human primates in Malaysia

Adrus M, Zainudin R, Ahamad M, Jayasilan MA, Abdullah MT

J Med Primatol, 2019 02;48(1):22-31.
PMID: 30370934 DOI: 10.1111/jmp.12389

BACKGROUND: A study was undertaken to determine gastrointestinal (GI) parasites commonly found in Malaysia's non-human primates (NHP) living in three different types of populations (wild, urban, and captive) and the basis of major GI parasites of zoonotic importance.
METHODS: A total of 308 samples was collected and microscopically screened from the NHP in the wild (n = 163), urban (n = 76), and captive (n = 69) populations. The samples were taken from 12 species of local NHPs.
RESULTS: At least, 44 species of GI parasites comprising of protozoans (seven species), nematodes (26 species), cestodes (five species), trematodes (five species), and pentastomida (one species) were detected. There were no significant differences for the overall prevalence and no great differences in GI parasite species among the wild, urban, and captive NHP populations.
CONCLUSION: The most common GI parasite was Ascaris spp. (49.7%), followed by Oesophagostomum spp. (26.9%), and 31 species discovered in this study are of known public health importance.
Fulltext New Insights on the Evolution of the Sweet Taste Receptor of Primates Adapted to Harsh Environments

Tamrin NAM, Zainudin R, Esa Y, Alias H, Isa MNM, Croft L, et al.

Animals (Basel), 2020 Dec 10;10(12).
PMID: 33321745 DOI: 10.3390/ani10122359

Taste perception is an essential function that provides valuable dietary and sensory information, which is crucial for the survival of animals. Studies into the evolution of the sweet taste receptor gene (TAS1R2) are scarce, especially for Bornean endemic primates such as Nasalis larvatus (proboscis monkey), Pongo pygmaeus (Bornean orangutan), and Hylobates muelleri (Muller's Bornean gibbon). Primates are the perfect taxa to study as they are diverse dietary feeders, comprising specialist folivores, frugivores, gummivores, herbivores, and omnivores. We constructed phylogenetic trees of the TAS1R2 gene for 20 species of anthropoid primates using four different methods (neighbor-joining, maximum parsimony, maximum-likelihood, and Bayesian) and also established the time divergence of the phylogeny. The phylogeny successfully separated the primates into their taxonomic groups as well as by their dietary preferences. Of note, the reviewed time of divergence estimation for the primate speciation pattern in this study was more recent than the previously published estimates. It is believed that this difference may be due to environmental changes, such as food scarcity and climate change, during the late Miocene epoch, which forced primates to change their dietary preferences. These findings provide a starting point for further investigation.
Fulltext Malaria parasites of long-tailed macaques in Sarawak, Malaysian Borneo: a novel species and demographic and evolutionary histories

Nada Raja T, Hu TH, Zainudin R, Lee KS, Perkins SL, Singh B

BMC Evol. Biol., 2018 04 10;18(1):49.
PMID: 29636003 DOI: 10.1186/s12862-018-1170-9

BACKGROUND: Non-human primates have long been identified to harbour different species of Plasmodium. Long-tailed macaques (Macaca fascicularis), in particular, are reservoirs for P. knowlesi, P. inui, P. cynomolgi, P. coatneyi and P. fieldi. A previous study conducted in Sarawak, Malaysian Borneo, however revealed that long-tailed macaques could potentially harbour novel species of Plasmodium based on sequences of small subunit ribosomal RNA and circumsporozoite genes. To further validate this finding, the mitochondrial genome and the apicoplast caseinolytic protease M genes of Plasmodium spp. were sequenced from 43 long-tailed macaque blood samples.
RESULTS: Apart from several named species of malaria parasites, long-tailed macaques were found to be potentially infected with novel species of Plasmodium, namely one we refer to as "P. inui-like." This group of parasites bifurcated into two monophyletic clades indicating the presence of two distinct sub-populations. Further analyses, which relied on the assumption of strict co-phylogeny between hosts and parasites, estimated a population expansion event of between 150,000 to 250,000 years before present of one of these sub-populations that preceded that of the expansion of P. knowlesi. Furthermore, both sub-populations were found to have diverged from a common ancestor of P. inui approximately 1.5 million years ago. In addition, the phylogenetic analyses also demonstrated that long-tailed macaques are new hosts for P. simiovale.
CONCLUSIONS: Malaria infections of long-tailed macaques of Sarawak, Malaysian Borneo are complex and include a novel species of Plasmodium that is phylogenetically distinct from P. inui. These macaques are new natural hosts of P. simiovale, a species previously described only in toque monkeys (Macaca sinica) in Sri Lanka. The results suggest that ecological factors could affect the evolution of malaria parasites.
Fulltext Disease progression in Plasmodium knowlesi malaria is linked to variation in invasion gene family members

Ahmed AM, Pinheiro MM, Divis PC, Siner A, Zainudin R, Wong IT, et al.

PLoS Negl Trop Dis, 2014 Aug;8(8):e3086.
PMID: 25121807 DOI: 10.1371/journal.pntd.0003086

Emerging pathogens undermine initiatives to control the global health impact of infectious diseases. Zoonotic malaria is no exception. Plasmodium knowlesi, a malaria parasite of Southeast Asian macaques, has entered the human population. P. knowlesi, like Plasmodium falciparum, can reach high parasitaemia in human infections, and the World Health Organization guidelines for severe malaria list hyperparasitaemia among the measures of severe malaria in both infections. Not all patients with P. knowlesi infections develop hyperparasitaemia, and it is important to determine why. Between isolate variability in erythrocyte invasion, efficiency seems key. Here we investigate the idea that particular alleles of two P. knowlesi erythrocyte invasion genes, P. knowlesi normocyte binding protein Pknbpxa and Pknbpxb, influence parasitaemia and human disease progression. Pknbpxa and Pknbpxb reference DNA sequences were generated from five geographically and temporally distinct P. knowlesi patient isolates. Polymorphic regions of each gene (approximately 800 bp) were identified by haplotyping 147 patient isolates at each locus. Parasitaemia in the study cohort was associated with markers of disease severity including liver and renal dysfunction, haemoglobin, platelets and lactate, (r = ≥ 0.34, p = <0.0001 for all). Seventy-five and 51 Pknbpxa and Pknbpxb haplotypes were resolved in 138 (94%) and 134 (92%) patient isolates respectively. The haplotypes formed twelve Pknbpxa and two Pknbpxb allelic groups. Patients infected with parasites with particular Pknbpxa and Pknbpxb alleles within the groups had significantly higher parasitaemia and other markers of disease severity. Our study strongly suggests that P. knowlesi invasion gene variants contribute to parasite virulence. We focused on two invasion genes, and we anticipate that additional virulent loci will be identified in pathogen genome-wide studies. The multiple sustained entries of this diverse pathogen into the human population must give cause for concern to malaria elimination strategists in the Southeast Asian region.