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Ng CKC, Kong RWH, Foo GH, Khoo G. Rapid comparison of precipitation data between satellite and in situ observations. Environ Monit Assess 2022; 195:228. [PMID: 36565392 DOI: 10.1007/s10661-022-10789-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/26/2022] [Indexed: 06/17/2023]
Abstract
The agriculture sector responsible for global food and nutrition security has an urgent need to examine climatic trends so that adaptations can be exercised in advance. Freely available dataset from satellite sources can greatly ease rainfall analysis, especially for smallholder farmers who typically operate under limited resources. Tests to determine their accuracy, however, are so far not deployed in tropical Southeast Asia. We compared in situ observations with dataset from the Global Satellite Mapping of Precipitation (GSMaP) and the Prediction of Worldwide Energy Resources (POWER) in two sites located 180 km apart in the tropical Malay Peninsula for 30 days. We found that in situ precipitation values were markedly overestimated by GSMaP (34.9-67.5%) and POWER (180.5-289.2%), and the possible reasons are discussed. Nonetheless, we conclude that GSMaP remains the best hope for smallholder farmers and its dataset can still be used under the precaution of error margins determined by the practical method described herein.
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Affiliation(s)
- Casey Keat-Chuan Ng
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
| | - Rachel Wan-Herng Kong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Gim-Hong Foo
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Gideon Khoo
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
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Selvarajan V, Wong A, Loh W, Ng Y, Nge C, Lau P, Khoo G, Loo B. Expanding T-cells using stirred-tank and a novel biaxial rotary bioreactor. Cytotherapy 2020. [DOI: 10.1016/j.jcyt.2020.03.316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ng CKC, Ooi PAC, Wong WL, Khoo G. First development of the Malaysian River Integrity Index (MyRII) based on biological, chemical and physical multi-metrics. J Environ Manage 2020; 255:109829. [PMID: 31783208 DOI: 10.1016/j.jenvman.2019.109829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 11/04/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Anthropogenic pressures are causing substantial degradation to the freshwater ecosystems globally and Malaysia has not escaped such a bleak scenario. Prompted by the predicament, this study's objective was to pioneer a river assessment system that can be readily adopted to monitor, manage and drive improvement in a wholesome manner. Three sets of a priori metrics were selected to form the Ichthyofaunal Quality Index (IQI: biological), Water Quality Index (WQI: chemical) and River Physical Quality Index (RPQI: physical). These indices were further integrated on equal weighting to construct a novel Malaysian River Integrity Index (MyRII). To test its robustness, the MyRII protocol was field tested in four eco-hydrological zones located in the Kampar River water basin for 18 months to reveal its strengths, weaknesses, and establish the "excellent", "good", "average", "poor" and "impaired" thresholds based on the "best performer" reference site in an empirical manner. The resultant MyRII showed a clear trend that corresponded with different levels of river impairment. Test site zone A which was a reference site with minimal disturbance achieved the highest MyRII (88.95 ± 4.29), followed by partially disturbed zone B (61.95 ± 5.90) and heavily disturbed zone C (50.00 ± 4.29). However, the MyRII in zone D (59.9 ± 6.39), which was a heavily disturbed wetland that was disjointed from the river, did not conform to such trend. Also unveiled and recognized, however, are some unexpected nuances, limitations and challenges that emerged from this study. These are critically discussed as precautions when interpreting and implementing the MyRII protocol. This study adds to the mounting body of evidence that water resource stakeholders and policymakers must look at the big picture and adopt the "balanced ecosystem" mind-set when assessing, restoring and managing the rivers as a freshwater resource.
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Affiliation(s)
- Casey Keat-Chuan Ng
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Peter Aun-Chuan Ooi
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Wey-Lim Wong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Gideon Khoo
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Perak, Malaysia.
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Ng CKC, Goh CH, Lin JC, Tan MS, Bong W, Yong CS, Chong JY, Ooi PAC, Wong WL, Khoo G. Water quality variation during a strong El Niño event in 2016: a case study in Kampar River, Malaysia. Environ Monit Assess 2018; 190:402. [PMID: 29904816 DOI: 10.1007/s10661-018-6784-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
El Niño and Southern Oscillation (ENSO) is a natural forcing that affects global climate patterns, thereon influencing freshwater quality and security. In the advent of a strong El Niño warming event in 2016 which induced an extreme dry weather in Malaysia, water quality variation was investigated in Kampar River which supplies potable water to a population of 92,850. Sampling points were stratified into four ecohydrological units and 144 water samples were examined from October 2015 to March 2017. The Malaysian Water Quality Index (WQI) and some supplementary parameters were analysed in the context of reduced precipitation. Data shows that prolonged dry weather, episodic and sporadic pollution incidents have caused some anomalies in dissolved oxygen (DO), total suspended solids (TSS), turbidity and ammoniacal nitrogen (AN) values recorded and the possible factors are discussed. The month of March and August 2016 recorded the lowest precipitation, but the overall resultant WQI remained acceptable. Since the occurrence of a strong El Niño event is infrequent and far between in decadal time scale, this paper gives some rare insights that may be central to monitoring and managing freshwater resource that has a crucial impact to the mass population in the region of Southeast Asia.
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Affiliation(s)
- Casey Keat-Chuan Ng
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia.
| | - Choo-Hou Goh
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Jia-Chun Lin
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Minn-Syenn Tan
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Willie Bong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Chea-Soon Yong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Jun-Yao Chong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Peter Aun-Chuan Ooi
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Wey-Lim Wong
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
| | - Gideon Khoo
- Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900, Kampar, Malaysia
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Wong BY, Awtar Singh TK, Khoo G, Alan Ong HK. Intra- and Inter-specific Variation of Four Acetes Species (Crustacea: Decapoda: Sergestidae) Sampled along the West Coast of Peninsular Malaysia. SAINS MALAYS 2017. [DOI: 10.17576/jsm-2017-4612-16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sow SLS, Khoo G, Chong LK, Smith TJ, Harrison PL, Ong HKA. Molecular diversity of the methanotrophic bacteria communities associated with disused tin-mining ponds in Kampar, Perak, Malaysia. World J Microbiol Biotechnol 2014; 30:2645-53. [PMID: 24929362 DOI: 10.1007/s11274-014-1687-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 06/07/2014] [Indexed: 11/25/2022]
Abstract
In a previous study, notable differences of several physicochemical properties, as well as the community structure of ammonia oxidizing bacteria as judged by 16S rRNA gene analysis, were observed among several disused tin-mining ponds located in the town of Kampar, Malaysia. These variations were associated with the presence of aquatic vegetation as well as past secondary activities that occurred at the ponds. Here, methane oxidizing bacteria (MOB), which are direct participants in the nutrient cycles of aquatic environments and biological indicators of environmental variations, have been characterised via analysis of pmoA functional genes in the same environments. The MOB communities associated with disused tin-mining ponds that were exposed to varying secondary activities were examined in comparison to those in ponds that were left to nature. Comparing the sequence and phylogenetic analysis of the pmoA clone libraries at the different ponds (idle, lotus-cultivated and post-aquaculture), we found pmoA genes indicating the presence of type I and type II MOB at all study sites, but type Ib sequences affiliated with the Methylococcus/Methylocaldum lineage were most ubiquitous (46.7 % of clones). Based on rarefaction analysis and diversity indices, the disused mining pond with lotus culture was observed to harbor the highest richness of MOB. However, varying secondary activity or sample type did not show a strong variation in community patterns as compared to the ammonia oxidizers in our previous study.
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Affiliation(s)
- S L S Sow
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar, 31900, Perak, Malaysia
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Thilagaratnam S, Ding YY, Au Eong KG, Chiam PC, Chow YL, Khoo G, Lim HB, Lim HYL, Lim WS, Lim WY, Peh KC, Phua KT, Sitoh YY, Tan BY, Wong SF, Wong WP, Yee R. Health Promotion Board-Ministry of Health clinical practice guidelines: functional screening for older adults in the community. Singapore Med J 2010; 51:518-522. [PMID: 20658114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The Health Promotion Board (HPB) and the Ministry of Health (MOH) publish clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the HPB-MOH clinical practice guidelines on Functional Screening for Older Adults in the Community, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Health Promotion Board website (http://www.hpb.gov.sg/uploadedFiles/HPB_Online/Publications/CPGFunctionalscreening.pdf). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
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Affiliation(s)
- S Thilagaratnam
- National University Hospital, National University of Singapore, Singapore.
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Lee CSS, Khoo G, Wong PS, Chong WA. EMB-007 Effect of ageing uterus on pregnancy outcome. Reprod Biomed Online 2008. [DOI: 10.1016/s1472-6483(10)61558-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lee CSS, Chen A, Singh S, Khoo G. EMB-009 Implantation rates in patients with and without PGD. Reprod Biomed Online 2008. [DOI: 10.1016/s1472-6483(10)61560-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Khoo G, Lim MH, Suresh H, Gan DKY, Lim KF, Chen F, Chan WK, Lim TM, Phang VPE. Genetic linkage maps of the guppy ( Poecilia reticulata): assignment of RAPD markers to multipoint linkage groups. Mar Biotechnol (NY) 2003; 5:279-293. [PMID: 14502400 DOI: 10.1007/s10126-002-0072-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2002] [Accepted: 08/20/2002] [Indexed: 05/24/2023]
Abstract
Genetic linkage maps of the guppy ( Poecilia reticulata) were constructed from independent crosses between the Tuxedo strain and a feral line (Wildtype). Segregation patterns of random amplified polymorphic DNA (RAPD) markers and phenotypic markers were investigated in F(2) offspring of Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol crosses. Among the 300 and 276 RAPD markers scored for the respective crosses, linkages were identified for 230 and 212, respectively. The Tuxedo male symbol male symbol x Wildtype female symbol female symbol and Wildtype male symbol male symbol x Tuxedo female symbol female symbol maps spanned 2100 Kosambi centiMorgans (cM(K)) and 1900 cM(K), respectively, in 28 linkage groups. Average marker resolution was 10 cM(K). Genome length was estimated at 4410 cM(K) and 4060 cM(K) for the respective crosses, with an average physical distance of 166 kbp/cM(K). Several RAPD markers were closely linked to or mapped onto the loci for the sex-determining region (SdR), and the sex-linked black caudal-peduncle ( Bcp) and red tail ( Rdt) genes. These primary linkage maps are the initial step toward the construction of a composite high-density map to facilitate map-based cloning and marker-assisted selection of quantitative trait loci that are essential for the development of comprehensive breeding programs for the guppy.
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Affiliation(s)
- Gideon Khoo
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore
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Khoo G, Lim KF, Gan DKY, Chen F, Chan WK, Lim TM, Phang VPE. Genetic diversity within and among feral populations and domesticated strains of the guppy (Poecilia reticulata) in Singapore. Mar Biotechnol (NY) 2002; 4:367-378. [PMID: 14961248 DOI: 10.1007/s10126-002-0007-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2001] [Accepted: 11/26/2001] [Indexed: 05/24/2023]
Abstract
Genetic variability within and among feral populations and cultured strains of the guppy (Poecilia reticulata) was investigated by random amplification of polymorphic DNA (RAPD) fingerprinting. Feral guppies were collected from 6 isolated populations (BT, Bukit Timah; NS, Nee Soon; TS, Tuas; MF, Mount Faber; KR, Kranji; LI, laboratory-inbred feral line), while the Tuxedo and Green Variegated strains were sampled from 2 guppy farms in Singapore. Pairwise genetic distances analyzed by unweighted pair-group method with arithmetic means revealed distinct clustering of guppy individuals into their respective populations and strains. Percentage polymorphic loci ranged from 54.96% (TS) to 68.70% (KR), while average heterozygosity ranged from 0.220 (GV) to 0.271 (KR). In contrast, TS guppies had the highest (0.850) intrapopulation genetic similarity (S), whereas KR had the lowest (0.781). Among populations and strains, S ranged from 0.703 (between GV and LI) to 0.809 (between NS and MB). The GV strain S was closer to TX (0.784) than to the feral guppies. Bootstrapped genetic distance trees depicted 3 major nodes comprising BT-TS, NS-MF, and TX-GV. Principal coordinate analysis also differentiated the 6 feral populations from the 2 cultured strains.
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Affiliation(s)
- Gideon Khoo
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore
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Khoo G, Lim TM, Chan WK, Phang VPE. Linkage Analysis and Mapping of Three Sex-Linked Color Pattern Genes in the Guppy, Poecilia reticulata. Zoolog Sci 1999. [DOI: 10.2108/zsj.16.893] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Phang VPE, Khoo G, Ang SP. Interaction between the Autosomal Recessive barGene and the Y-Linked Snakeskin Body ( Ssb) Pattern Gene in the Guppy, Poecilia reticulata. Zoolog Sci 1999. [DOI: 10.2108/zsj.16.905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Khoo G, Lim TM, Chan WK, Phang VPE. Sex-Linkage of the Black Caudal-Peduncle and Red Tail Genes in the Tuxedo Strain of the Guppy, Poecilia reticulata. Zoolog Sci 1999. [DOI: 10.2108/zsj.16.629] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sherrid M, Goyal A, Delia E, Khoo G, Heropoulos M, McCabe JB, Dwyer EM. Unsuspected mitral stenosis. Am J Med 1991; 90:189-92. [PMID: 1996586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE AND PATIENTS AND METHODS We observed a series of patients in whom the diagnosis of mitral stenosis was first discovered in the echocardiography laboratory. Because of this experience, we examined the records of 152 patients with echocardiographic evidence of rheumatic mitral stenosis to determine the clinical characteristics and course of patients with unsuspected mitral stenosis as well as those factors that may have obscured the diagnosis. RESULTS Of these 152 patients, 18 had mitral stenosis that was unsuspected clinically until the echocardiogram. These patients were elderly, with a median age of 72 years. They were all referred for echocardiography because of cardiac symptoms. Eight patients were referred for evaluation of congestive heart failure. Five patients were referred for evaluation of aortic valve disease. Three patients were referred because of cerebrovascular accidents and atrial fibrillation. The Doppler-determined mean diastolic mitral gradient ranged from 4 to 15 mm Hg (mean: 7 mm Hg). Mitral stenosis ranged in severity from trivial to very severe. Eight patients had moderate to severe mitral stenosis with estimated mitral valve areas less than or equal to 1.5 cm2. Seven had mild or trivial mitral stenosis with estimated mitral valve areas greater than 1.5 cm2. After further evaluation, two patients underwent mitral valve surgery with improvement of congestive failure. In three patients, warfarin therapy was begun to prevent emboli. Thus, five of 18 patients had a significant immediate change in therapy because of the discovery of mitral stenosis. CONCLUSION The diagnosis of mitral stenosis may not be suspected in the presence of advanced age, other serious cardiac and medical conditions, or mechanical factors that complicate the physical examination. In these patients, mitral stenosis may be hemodynamically significant and may cause significant symptoms.
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Affiliation(s)
- M Sherrid
- Department of Medicine, St. Luke's-Roosevelt Hospital, New York, New York
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