MyMedR

Displaying publications 441 - 460 of 660 in total

Abstract:

Sort:

Fulltext If doctors and nurses said vaping is safe ... it is safe… why not! A study on the acceptance of e-cigarettes among future healthcare providers in one of higher learning institutions in East Malaysia. [Abstract]

Hamidah H, Theresa A, Jennifer D Y, Nurfarina NJ, Siti Aisyah W

Malaysian Journal of Medicine and Health Sciences, 2020;16(105):20.
MyJurnal

1st UMS INTERNATIONAL NURSING CONFERENCE IN CONJUNCTION WITH 11TH INTERNATIONAL NURSING STUDENTS’ FORUM. A view into the future of nursing: Nursing Transformation towards IR-4.0
Held at the Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia. On 6-8th March 2020
Introduction: Vaping is a use of electronic devices which do not produce smoke or steam, rather an aerosol consisting of fine particles, containing varying amounts of propylene glycol, glycerine, flavourings and other chemicals. It is battery-powered devices that mimic the action of smoking. In Malaysia, vaping has become a major trend. Videos are going viral on social media showing school students in uniform proudly puffing away. The aim of this study was to find out the acceptance of vaping among medical and nursing students.
Methods: A descriptive cross-sectional study with multiple stage of sampling technique on population of 624 medical and nursing students. Total samples were 389, by Krejci Morgan (1970) sampling technique. Structured questionnaires by A. Gorukanti (2018) with 15 items consisted of knowledge, attitude and acceptance and attitude and believe as data collection tools.
Results: Results showed 9% to 10% of respondents are still smoking, they believed e-cigarette is safe and would not affect one’s health, as it is a water-based product trademarked. They also regard e-cigarette a way of quitting or cutting down smoking.
Conclusion: 10% of respondents consistently believed e-cigarettes is harmless. Although the percentage may look small but the impact on the public is huge. However, 90% strongly agreed e-cigarettes ‘vapour is dan- gerous to babies and kids. What concerns us is the consistent group of the 10%, are students who will become our healthcare providers in the future. Their strong-belief in vaping will influence the future of the public understanding, “If doctors and nurses said vaping is safe ... it is safe… right? why not. which is harmful. However, this study has impelled us not only to look at the strength and the significance outcomes of study and neglecting the trifle ones that may prime to serious healthcare consequences of the future society.

Matched MeSH terms: Borneo
Ethnobotanical study of medicinal plants used by the Kenyah community of Borneo

Sundara Rajoo K, Lepun P, Alan R, Singh Karam D, Abdu A, Rosli Z, et al.

J Ethnopharmacol, 2023 Jan 30;301:115780.
PMID: 36202163 DOI: 10.1016/j.jep.2022.115780

ETHNOPHARMACOLOGICAL RELEVANCE: Sarawak is located in one of the world's most biodiverse regions and is home to more than 40 sub-ethnic groups that each have their own distinct culture, language and lifestyle. This has given rise to numerous, unique ethnobotanical systems. However, due to rapid urbanization, this traditional knowledge is at a risk of extinction. Yet, ethnobotanical studies in Sarawak are almost non-existent, especially among Orang Ulu communities like the Kenyah.
AIM OF STUDY: Therefore, this study was conducted to document the ethnomedicinal knowledge of the Kenyah community. The main objectives of this study are: 1) To determine and document the diversity of medicinal plants used by the Kenyah community, 2) To determine whether the availability of modern medicine has affected Kenyah traditional medicine, and 3) To identify plants which have not been previously cited or used for previously unreported medical uses.
MATERIALS AND METHODS: We conducted repeated interviews and field surveys at the Asap-Koyan Resettlement Area, Belaga Sarawak. A total of 24 respondents from four Kenyah longhouses were interviewed in this study. Individuals possessing extensive traditional medicinal knowledge were identified via preliminary interviews or by viva voce. Translators were employed to ensure that there was no miscommunication. The results were evaluated based on the plant's total use-reports and number of respondents citing the plant. The data was also evaluated based on use-reports by ailment category.
RESULTS: Over 95% of the respondents were 40 years and older (58.21 years old ± 11.21). This was due to the younger members of the community (40 years old and below) admitting that they had almost no knowledge regarding traditional medicine, as they preferred relying on modern medicine. A total of 61 plant species were mentioned by the 24 respondents Seven plants had five or more respondents citing it, which was more than 20% of the respondents. These plants were Piper betle, Homalomena cordata, Senna alata, Annona muricata, Derris elliptica, Blumea balsamifera and Coscinium fenestratum.
CONCLUSION: Almost all of the cited plants had been previously recorded to be used in either Ayurvedic, Chinese herbal medicine, Malay traditional medicine or other Asian ethnomedicinal systems. However, there were four highly cited species that were used for treatments that were scarcely reported in past literature. These were piper betle (used by Kenyah to treat fever), Sauropus andrognus (used by Kenyah to treat fever), Derris elliptica (used by Kenyah to treat fever and influenza) and Coscinuim fenestratum (used by Kenyah to treat toxic effects from non-medical substances).

Matched MeSH terms: Borneo
Plasmodium knowlesi Duffy binding protein alpha region II (PkDBPαII) in clinical isolates from Peninsular Malaysia and Malaysian Borneo exhibit different immune responses in animal models

Azlan UK, Cheong FW, Lau YL, Fong MY

Parasitol Res, 2022 Dec;121(12):3443-3454.
PMID: 36152079 DOI: 10.1007/s00436-022-07665-7

Plasmodium knowlesi utilizes the Duffy binding protein alpha (PkDBPα) to facilitate its invasion into human erythrocytes. PkDBPα region II (PkDBPαII) from Peninsular Malaysia and Malaysian Borneo has been shown to occur as distinct haplotypes, and the predominant haplotypes from these geographical areas demonstrated differences in binding activity to human erythrocytes in erythrocyte binding assays. This study aimed to determine the effects of genetic polymorphisms in PkDBPαII to immune responses in animal models. The recombinant PkDBPαII (~ 45 kDa) of Peninsular Malaysia (PkDBPαII-H) and Malaysian Borneo (PkDBPαII-S) were expressed in a bacterial expression system, purified, and used in mice and rabbit immunization. The profile of cytokines IL-1ra, IL-2, IL-6, IL-10, TNF-α, and IFN-γ in immunized mice spleen was determined via ELISA. The titer and IgG subtype distribution of raised antibodies was characterized. Immunized rabbit sera were purified and used to perform an in vitro merozoite invasion inhibition assay. The PkDBPαII-immunized mice sera of both groups showed high antibody titer and a similar IgG subtype distribution pattern: IgG2b > IgG1 > IgG2a > IgG3. The PkDBPαII-H group was shown to have higher IL-1ra (P = 0.141) and IL-6 (P = 0.049) concentrations, with IL-6 levels significantly higher than that of the PkDBPαII-S group (P ≤ 0.05). Merozoite invasion inhibition assay using purified anti-PkDBPαII antibodies showed a significantly higher inhibition rate in the PkDBPαII-H group than the PkDBPαII-S group (P ≤ 0.05). Besides, anti-PkDBPαII-H antibodies were able to exhibit inhibition activity at a lower concentration than anti-PkDBPαII-S antibodies. PkDBPαII was shown to be immunogenic, and the PkDBPαII haplotype from Peninsular Malaysia exhibited higher responses in cytokines IL-1ra and IL-6, antibody IgM level, and merozoite invasion inhibition assay than the Malaysian Borneo haplotype. This suggests that polymorphisms in the PkDBPαII affect the level of immune responses in the host.

Matched MeSH terms: Borneo
Fulltext The critical role of natural forest as refugium for generalist species in oil palm-dominated landscapes

Guerrero-Sanchez S, Goossens B, Saimin S, Orozco-terWengel P

PLoS One, 2021;16(10):e0257814.
PMID: 34614000 DOI: 10.1371/journal.pone.0257814

In Borneo, oil palm plantations have replaced much of natural resources, where generalist species tend to be the principal beneficiaries, due to the abundant food provided by oil palm plantations. Here, we analyse the distribution of the Asian water monitor lizard (Varanus salvator) population within an oil palm-dominated landscape in the Kinabatangan floodplain, Malaysian Borneo. By using mark-recapture methods we estimated its population size, survival, and growth in forest and plantation habitats. We compared body measurements (i.e. body weight and body length) of individuals living in forest and oil palm habitats as proxy for the population's health status, and used general least squares estimation models to evaluate its response to highly fragmented landscapes in the absence of intensive hunting pressures. Contrary to previous studies, the abundance of lizards was higher in the forest than in oil palm plantations. Recruitment rates were also higher in the forest, suggesting that these areas may function as a source of new individuals into the landscape. While there were no morphometric differences among plantation sites, we found significant differences among forested areas, where larger lizards were found inhabiting forest adjacent to oil palm plantations. Although abundant in food resources, the limited availability of refugia in oil palm plantations may intensify intra-specific encounters and competition, altering the body size distribution in plantation populations, contrary to what happens in the forest. We conclude that large patches of forest, around and within oil palm plantations, are essential for the dynamics of the monitor lizard population in the Kinabatangan floodplain, as well as a potential source of individuals to the landscape. We recommend assessing this effect in other generalist species, as well as the impact on the prey communities, especially to reinforce the establishment of buffer zones and corridors as a conservation strategy within plantations.

Matched MeSH terms: Borneo
Fulltext Ancient divergence time estimates in Eutropis rugifera support the existence of Pleistocene barriers on the exposed Sunda Shelf

Karin BR, Das I, Jackman TR, Bauer AM

PeerJ, 2017;5:e3762.
PMID: 29093993 DOI: 10.7717/peerj.3762

Episodic sea level changes that repeatedly exposed and inundated the Sunda Shelf characterize the Pleistocene. Available evidence points to a more xeric central Sunda Shelf during periods of low sea levels, and despite the broad land connections that persisted during this time, some organisms are assumed to have faced barriers to dispersal between land-masses on the Sunda Shelf. Eutropis rugifera is a secretive, forest adapted scincid lizard that ranges across the Sunda Shelf. In this study, we sequenced one mitochondrial (ND2) and four nuclear (BRCA1, BRCA2, RAG1, and MC1R) markers and generated a time-calibrated phylogeny in BEAST to test whether divergence times between Sundaic populations of E. rugifera occurred during Pleistocene sea-level changes, or if they predate the Pleistocene. We find that E. rugifera shows pre-Pleistocene divergences between populations on different Sundaic land-masses. The earliest divergence within E. rugifera separates the Philippine samples from the Sundaic samples approximately 16 Ma; the Philippine populations thus cannot be considered conspecific with Sundaic congeners. Sundaic populations diverged approximately 6 Ma, and populations within Borneo from Sabah and Sarawak separated approximately 4.5 Ma in the early Pliocene, followed by further cladogenesis in Sarawak through the Pleistocene. Divergence of peninsular Malaysian populations from the Mentawai Archipelago occurred approximately 5 Ma. Separation among island populations from the Mentawai Archipelago likely dates to the Pliocene/Pleistocene boundary approximately 3.5 Ma, and our samples from peninsular Malaysia appear to coalesce in the middle Pleistocene, about 1 Ma. Coupled with the monophyly of these populations, these divergence times suggest that despite consistent land-connections between these regions throughout the Pleistocene E. rugifera still faced barriers to dispersal, which may be a result of environmental shifts that accompanied the sea-level changes.

Matched MeSH terms: Borneo
Fulltext Land snails of Leptopoma Pfeiffer, 1847 in Sabah, Northern Borneo (Caenogastropoda: Cyclophoridae): an analysis of molecular phylogeny and geographical variations in shell form

Phung CC, Heng PS, Liew TS

PeerJ, 2017;5:e3981.
PMID: 29104827 DOI: 10.7717/peerj.3981

Leptopoma is a species rich genus with approximately 100 species documented. Species-level identification in this group has been based on shell morphology and colouration, as well as some anatomical features based on small sample sizes. However, the implications of the inter- and intra-species variations in shell form to the taxonomy of Leptopoma species and the congruency of its current shell based taxonomy with its molecular phylogeny are still unclear. There are four Leptopoma species found in Sabah, Borneo, and their taxonomy status remains uncertain due to substantial variation in shell forms. This study focuses on the phylogenetic relationships and geographical variation in shell form of three Leptopoma species from Sabah. The phylogenetic relationship of these species was first estimated by performing Maximum Likelihood and Bayesian analysis based on mitochondrial genes (16S rDNA and COI) and nuclear gene (ITS-1). Then, a total of six quantitative shell characters (i.e., shell height, shell width, aperture height, aperture width, shell spire height, and ratio of shell height to width) and three qualitative shell characters (i.e., shell colour patterns, spiral ridges, and dark apertural band) of the specimens were mapped across the phylogenetic tree and tested for phylogenetic signals. Data on shell characters of Leptopoma sericatum and Leptopoma pellucidum from two different locations (i.e., Balambangan Island and Kinabatangan) where both species occurred sympatrically were then obtained to examine the geographical variations in shell form. The molecular phylogenetic analyses suggested that each of the three Leptopoma species was monophyletic and indicated congruence with only one of the shell characters (i.e., shell spiral ridges) in the current morphological-based classification. Although the geographical variation analyses suggested some of the shell characters indicating inter-species differences between the two Leptopoma species, these also pointed to intra-species differences between populations from different locations. This study on Leptopoma species is based on small sample size and the findings appear only applicable to Leptopoma species in Sabah. Nevertheless, we anticipate this study to be a starting point for more detailed investigations to include the other still little-known (ca. 100) Leptopoma species and highlights a need to assess variations in shell characters before they could be used in species classification.

Matched MeSH terms: Borneo
Resistance of tropical seedlings to drought is mediated by neighbourhood diversity

O'Brien MJ, Reynolds G, Ong R, Hector A

Nat Ecol Evol, 2017 Nov;1(11):1643-1648.
PMID: 28963453 DOI: 10.1038/s41559-017-0326-0

Occasional periods of drought are typical of most tropical forests, but climate change is increasing drought frequency and intensity in many areas across the globe, threatening the structure and function of these ecosystems. The effects of intermittent drought on tropical tree communities remain poorly understood and the potential impacts of intensified drought under future climatic conditions are even less well known. The response of forests to altered precipitation will be determined by the tolerances of different species to reduced water availability and the interactions among plants that alleviate or exacerbate the effects of drought. Here, we report the response of experimental monocultures and mixtures of tropical trees to simulated drought, which reveals a fundamental shift in the nature of interactions among species. Weaker competition for water in diverse communities allowed seedlings to maintain growth under drought while more intense competition among conspecifics inhibited growth under the same conditions. These results show that reduced competition for water among species in mixtures mediates community resistance to drought. The delayed onset of competition for water among species in more diverse neighbourhoods during drought has potential implications for the coexistence of species in tropical forests and the resilience of these systems to climate change.

Matched MeSH terms: Borneo
Fulltext Feeding strategies and competition between terrestrial Haemadipsa leeches (Euhirudinea: Arhynchobdellida) in Danum Valley rainforest (Borneo, Sabah)

Gasiorek P, Rozycka H

Folia Parasitol., 2017 10 03;64.
PMID: 28980971 DOI: 10.14411/fp.2017.031

Haemadipsid leeches are among the most successful terrestrial invertebrates in Bornean rainforests. They are very common ectoparasites of vertebrates, and their abundance has facilitated the conduction of numerous projects in the fields of ecology, zoogeography and taxonomy. We undertook research on two species inhabiting lowland dipterocarp forest, Haemadipsa picta Moore, 1929 and Haemadipsa subagilis (Moore, 1929), in order to address the following questions: (a) is there a difference in leech abundance between trails and off-trails?; (b) is ambush location dependent on specimen size or is species-specific?; (c) is intra- and interspecific competition limited by differences in foraging behaviours or vertical niche partitioning? Our results clearly show that H. picta is more abundant on trails than on off-trails and is vertically dispersed within the understory; the size of a specimen is strongly correlated with plant height. Haemadipsa subagilis was found not to exhibit such patterns. We suggest a possible lowering of interspecific competition between these species as a result of: (i) size-dependent dispersion of H. picta (together with reduction of intraspecific competition); and (ii) habitat specialisation of H. subagilis. Moreover, we provide new observations on their foraging behaviour.

Matched MeSH terms: Borneo
Fulltext Characterisation of the semi-volatile component of Dissolved Organic Matter by Thermal Desorption - Proton Transfer Reaction - Mass Spectrometry

Materić D, Peacock M, Kent M, Cook S, Gauci V, Röckmann T, et al.

Sci Rep, 2017 Nov 21;7(1):15936.
PMID: 29162906 DOI: 10.1038/s41598-017-16256-x

Proton Transfer Reaction - Mass Spectrometry (PTR-MS) is a sensitive, soft ionisation method suitable for qualitative and quantitative analysis of volatile and semi-volatile organic vapours. PTR-MS is used for various environmental applications including monitoring of volatile organic compounds (VOCs) emitted from natural and anthropogenic sources, chemical composition measurements of aerosols, etc. Here we apply thermal desorption PTR-MS for the first time to characterise the chemical composition of dissolved organic matter (DOM). We developed a clean, low-pressure evaporation/sublimation system to remove water from samples and coupled it to a custom-made thermal desorption unit to introduce the samples to the PTR-MS. Using this system, we analysed waters from intact and degraded peat swamp forest of Kalimantan, Indonesian Borneo, and an oil palm plantation and natural forest in Sarawak, Malaysian Borneo. We detected more than 200 organic ions from these samples and principal component analysis allowed clear separation of the different sample origins based on the composition of organic compounds. The method is sensitive, reproducible, and provides a new and comparatively cheap tool for a rapid characterisation of water and soil DOM.

Matched MeSH terms: Borneo
Fulltext Recycling of phenolic compounds in Borneo's tropical peat swamp forests

Yule CM, Lim YY, Lim TY

Carbon Balance Manag, 2018 Feb 07;13(1):3.
PMID: 29417248 DOI: 10.1186/s13021-018-0092-6

BACKGROUND: Tropical peat swamp forests (TPSF) are globally significant carbon stores, sequestering carbon mainly as phenolic polymers and phenolic compounds (particularly as lignin and its derivatives) in peat layers, in plants, and in the acidic blackwaters. Previous studies show that TPSF plants have particularly high levels of phenolic compounds which inhibit the decomposition of organic matter and thus promote peat accumulation. The studies of phenolic compounds are thus crucial to further understand how TPSF function with respect to carbon sequestration. Here we present a study of cycling of phenolic compounds in five forests in Borneo differing in flooding and acidity, leaching of phenolic compounds from senescent Macaranga pruinosa leaves, and absorption of phenolics by M. pruinosa seedlings.
RESULTS: The results of the study show that total phenolic content (TPC) in soil and leaves of three species of Macaranga were highest in TPSF followed by freshwater swamp forest and flooded limestone forest, then dry land sites. Highest TPC values were associated with acidity (in TPSF) and waterlogging (in flooded forests). Moreover, phenolic compounds are rapidly leached from fallen senescent leaves, and could be reabsorbed by tree roots and converted into more complex phenolics within the leaves.
CONCLUSIONS: Extreme conditions-waterlogging and acidity-may facilitate uptake and synthesis of protective phenolic compounds which are essential for impeded decomposition of organic matter in TPSF. Conversely, the ongoing drainage and degradation of TPSF, particularly for conversion to oil palm plantations, reverses the conditions necessary for peat accretion and carbon sequestration.

Matched MeSH terms: Borneo
Logging disturbance shifts net primary productivity and its allocation in Bornean tropical forests

Riutta T, Malhi Y, Kho LK, Marthews TR, Huaraca Huasco W, Khoo M, et al.

Glob Chang Biol, 2018 07;24(7):2913-2928.
PMID: 29364562 DOI: 10.1111/gcb.14068

Tropical forests play a major role in the carbon cycle of the terrestrial biosphere. Recent field studies have provided detailed descriptions of the carbon cycle of mature tropical forests, but logged or secondary forests have received much less attention. Here, we report the first measures of total net primary productivity (NPP) and its allocation along a disturbance gradient from old-growth forests to moderately and heavily logged forests in Malaysian Borneo. We measured the main NPP components (woody, fine root and canopy NPP) in old-growth (n = 6) and logged (n = 5) 1 ha forest plots. Overall, the total NPP did not differ between old-growth and logged forest (13.5 ± 0.5 and 15.7 ± 1.5 Mg C ha-1 year-1 respectively). However, logged forests allocated significantly higher fraction into woody NPP at the expense of the canopy NPP (42% and 48% into woody and canopy NPP, respectively, in old-growth forest vs 66% and 23% in logged forest). When controlling for local stand structure, NPP in logged forest stands was 41% higher, and woody NPP was 150% higher than in old-growth stands with similar basal area, but this was offset by structure effects (higher gap frequency and absence of large trees in logged forest). This pattern was not driven by species turnover: the average woody NPP of all species groups within logged forest (pioneers, nonpioneers, species unique to logged plots and species shared with old-growth plots) was similar. Hence, below a threshold of very heavy disturbance, logged forests can exhibit higher NPP and higher allocation to wood; such shifts in carbon cycling persist for decades after the logging event. Given that the majority of tropical forest biome has experienced some degree of logging, our results demonstrate that logging can cause substantial shifts in carbon production and allocation in tropical forests.

Matched MeSH terms: Borneo
Genetic relatedness of indigenous ethnic groups in northern Borneo to neighboring populations from Southeast Asia, as inferred from genome-wide SNP data

Yew CW, Hoque MZ, Pugh-Kitingan J, Minsong A, Voo CLY, Ransangan J, et al.

Ann. Hum. Genet., 2018 07;82(4):216-226.
PMID: 29521412 DOI: 10.1111/ahg.12246

The region of northern Borneo is home to the current state of Sabah, Malaysia. It is located closest to the southern Philippine islands and may have served as a viaduct for ancient human migration onto or off of Borneo Island. In this study, five indigenous ethnic groups from Sabah were subjected to genome-wide SNP genotyping. These individuals represent the "North Borneo"-speaking group of the great Austronesian family. They have traditionally resided in the inland region of Sabah. The dataset was merged with public datasets, and the genetic relatedness of these groups to neighboring populations from the islands of Southeast Asia, mainland Southeast Asia and southern China was inferred. Genetic structure analysis revealed that these groups formed a genetic cluster that was independent of the clusters of neighboring populations. Additionally, these groups exhibited near-absolute proportions of a genetic component that is also common among Austronesians from Taiwan and the Philippines. They showed no genetic admixture with Austro-Melanesian populations. Furthermore, phylogenetic analysis showed that they are closely related to non-Austro-Melansian Filipinos as well as to Taiwan natives but are distantly related to populations from mainland Southeast Asia. Relatively lower heterozygosity and higher pairwise genetic differentiation index (FST ) values than those of nearby populations indicate that these groups might have experienced genetic drift in the past, resulting in their differentiation from other Austronesians. Subsequent formal testing suggested that these populations have received no gene flow from neighboring populations. Taken together, these results imply that the indigenous ethnic groups of northern Borneo shared a common ancestor with Taiwan natives and non-Austro-Melanesian Filipinos and then isolated themselves on the inland of Sabah. This isolation presumably led to no admixture with other populations, and these individuals therefore underwent strong genetic differentiation. This report contributes to addressing the paucity of genetic data on representatives from this strategic region of ancient human migration event(s).

Matched MeSH terms: Borneo
Extensive sharing of mitochondrial COI and CYB haplotypes among reef-building staghorn corals (Acropora spp.) in Sabah, North Borneo

Robert R, Rodrigues KF, Waheed Z, Kumar SV

Mitochondrial DNA A DNA Mapp Seq Anal, 2019 01;30(1):16-23.
PMID: 29521145 DOI: 10.1080/24701394.2018.1448080

This study is aimed at establishing a baseline on the genetic diversity of the Acropora corals of Sabah, North Borneo based on variations in the partial COI and CYB nucleotide sequences. Comparison across 50 shallow-water Acropora morphospecies indicated that the low substitution rates in the two genes were due to negative selection and that rate heterogeneity between them was asymmetric. CYB appeared to have evolved faster than COI in the Acropora as indicated by differences in the rate of pairwise genetic distance, degrees of transition bias (Ts/Tv), synonymous-to-nonsynonymous rate ratio (dN/dS), and substitution patterns at the three codon positions. Despite the relatively high haplotype diversity (Hd), nucleotide diversity (π) of the haplotype datasets was low due to stringent purifying selection operating on the genes. Subsequently, we identified individual COI and CYB haplotypes that were each extensively shared across sympatrically and allopatrically distributed Indo-Pacific Acropora. These reciprocally common mtDNA types were suspected to be ancestral forms of the genes whereas other haplotypes have mostly evolved from autoapomorphic mutations which have not been fixed within the species even though they are selectively neutral. To our knowledge, this is the first report on DNA barcodes of Acropora species in North Borneo and this understanding will play an important role in the management and conservation of these important reef-building corals.

Matched MeSH terms: Borneo
Speciation in Indo-Pacific swiftlets (Aves: Apodidae): integrating molecular and phenotypic data for a new provisional taxonomy of the Collocalia esculenta complex

Rheindt FE, Christidis L, Norman JA, Eaton JA, Sadanandan KR, Schodde R

Zootaxa, 2017 Apr 07;4250(5):401-433.
PMID: 28609999 DOI: 10.11646/zootaxa.4250.5.1

White-bellied swiftlets of the Collocalia esculenta complex constitute a radiation of colony-breeding swifts distributed throughout the tropical Indo-Pacific region. Resolution of their taxonomy is challenging due to their morphological uniformity. To analyze the evolutionary history of this complex, we combine new biometric measurements and results from plumage assessment of museum specimens with novel as well as previously published molecular data. Together, this body of information constitutes the largest systematic dataset for white-bellied swiftlets yet compiled, drawn from 809 individuals belonging to 32 taxa for which new molecular, biometric, and/or plumage data are presented. We propose changing the classification of white-bellied swiftlets, for which two species are currently recognized, to elevate eight regional forms to species level, and we also describe two new subspecies. The ten taxa we recommend recognizing at the species level are: Collocalia linchi (Java to Lombok, Sumatran hills), C. dodgei (montane Borneo), C. natalis (Christmas Island), C. affinis (Greater Sundas, including the Thai-Malay Peninsula and Andaman-Nicobar Islands), C. marginata (Philippines), C. isonota (Philippines), C. sumbawae (west Lesser Sundas), C. neglecta (east Lesser Sundas), C. esculenta (Sulawesi, Moluccas, New Guinea, Bismarck Archipelago, Solomon Islands), and C. uropygialis (Vanuatu, New Caledonia). Future molecular and morphological work is needed to resolve questions of speciation and population affinities in the Philippines, Christmas Island, Wallacea and central Melanesia, and to shed light on historic diversification and patterns of gene flow in the complex.

Matched MeSH terms: Borneo
Fulltext Spatio-temporal distribution and hotspots of Plasmodium knowlesi infections in Sarawak, Malaysian Borneo

Yunos NE, Sharkawi HM, Hii KC, Hu TH, Mohamad DSA, Rosli N, et al.

Sci Rep, 2022 Oct 14;12(1):17284.
PMID: 36241678 DOI: 10.1038/s41598-022-21439-2

Plasmodium knowlesi infections in Malaysia are a new threat to public health and to the national efforts on malaria elimination. In the Kapit division of Sarawak, Malaysian Borneo, two divergent P. knowlesi subpopulations (termed Cluster 1 and Cluster 2) infect humans and are associated with long-tailed macaque and pig-tailed macaque hosts, respectively. It has been suggested that forest-associated activities and environmental modifications trigger the increasing number of knowlesi malaria cases. Since there is a steady increase of P. knowlesi infections over the past decades in Sarawak, particularly in the Kapit division, we aimed to identify hotspots of knowlesi malaria cases and their association with forest activities at a geographical scale using the Geographic Information System (GIS) tool. A total of 1064 P. knowlesi infections from 2014 to 2019 in the Kapit and Song districts of the Kapit division were studied. Overall demographic data showed that males and those aged between 18 and 64 years old were the most frequently infected (64%), and 35% of infections involved farming activities. Thirty-nine percent of Cluster 1 infections were mainly related to farming surrounding residential areas while 40% of Cluster 2 infections were associated with activities in the deep forest. Average Nearest Neighbour (ANN) analysis showed that humans infected with both P. knowlesi subpopulations exhibited a clustering distribution pattern of infection. The Kernel Density Analysis (KDA) indicated that the hotspot of infections surrounding Kapit and Song towns were classified as high-risk areas for zoonotic malaria transmission. This study provides useful information for staff of the Sarawak State Vector-Borne Disease Control Programme in their efforts to control and prevent zoonotic malaria.

Matched MeSH terms: Borneo
Fulltext Ovarian neoplasms in Sarawak

Kothare SN

Singapore Med J, 1980 Dec;21(6):756-9.
PMID: 7221588

This is an analysis of ovarian neoplasms encountered in Sarawak during the period January 1976-December 1977. There were 149 benign and 36 primary malignant tumours with an incidence of 44.3 per cent and 23.6 per cent respectively, in neoplasms 01 the Reproductive System. Amongst the benign ovarian tumours Dermoid Cyst
(Cystic Teratoma) was quite frequent (29.5 per cent). In malignant neoplasms Cystadenocarcinomas constituted 66.7 per cent of the total. A case each of Granulosa cell earcinoma, Adenoacanthoma and Endodermal sinus tumours, 4 of Dysgerminoma and 6 of metastatic ovarian tumours were also recorded.

Matched MeSH terms: Borneo
Fulltext Logged tropical forests have amplified and diverse ecosystem energetics

Malhi Y, Riutta T, Wearn OR, Deere NJ, Mitchell SL, Bernard H, et al.

Nature, 2022 Dec;612(7941):707-713.
PMID: 36517596 DOI: 10.1038/s41586-022-05523-1

Old-growth tropical forests are widely recognized as being immensely important for their biodiversity and high biomass1. Conversely, logged tropical forests are usually characterized as degraded ecosystems2. However, whether logging results in a degradation in ecosystem functions is less clear: shifts in the strength and resilience of key ecosystem processes in large suites of species have rarely been assessed in an ecologically integrated and quantitative framework. Here we adopt an ecosystem energetics lens to gain new insight into the impacts of tropical forest disturbance on a key integrative aspect of ecological function: food pathways and community structure of birds and mammals. We focus on a gradient spanning old-growth and logged forests and oil palm plantations in Borneo. In logged forest there is a 2.5-fold increase in total resource consumption by both birds and mammals compared to that in old-growth forests, probably driven by greater resource accessibility and vegetation palatability. Most principal energetic pathways maintain high species diversity and redundancy, implying maintained resilience. Conversion of logged forest into oil palm plantation results in the collapse of most energetic pathways. Far from being degraded ecosystems, even heavily logged forests can be vibrant and diverse ecosystems with enhanced levels of ecological function.

Matched MeSH terms: Borneo
Effects of rainfall exclusion on leaf gas exchange traits and osmotic adjustment in mature canopy trees of Dryobalanops aromatica (Dipterocarpaceae) in a Malaysian tropical rain forest

Inoue Y, Ichie T, Kenzo T, Yoneyama A, Kumagai T, Nakashizuka T

Tree Physiol, 2017 10 01;37(10):1301-1311.
PMID: 28541561 DOI: 10.1093/treephys/tpx053

Climate change exposes vegetation to unusual levels of drought, risking a decline in productivity and an increase in mortality. It still remains unclear how trees and forests respond to such unusual drought, particularly Southeast Asian tropical rain forests. To understand leaf ecophysiological responses of tropical rain forest trees to soil drying, a rainfall exclusion experiment was conducted on mature canopy trees of Dryobalanops aromatica Gaertn.f. (Dipterocarpaceae) for 4 months in an aseasonal tropical rain forest in Sarawak, Malaysia. The rainfall was intercepted by using a soft vinyl chloride sheet. We compared the three control and three treatment trees with respect to leaf water use at the top of the crown, including stomatal conductance (gsmax), photosynthesis (Amax), leaf water potential (predawn: Ψpre; midday: Ψmid), leaf water potential at turgor loss point (πtlp), osmotic potential at full turgor (π100) and a bulk modulus of elasticity (ε). Measurements were taken using tree-tower and canopy-crane systems. During the experiment, the treatment trees suffered drought stress without evidence of canopy dieback in comparison with the control trees; e.g., Ψpre and Ψmid decreased with soil drying. Minimum values of Ψmid in the treatment trees decreased during the experiment, and were lower than πtlp in the control trees. However, the treatment trees also decreased their πtlp by osmotic adjustment, and the values were lower than the minimum values of their Ψmid. In addition, the treatment trees maintained gs and Amax especially in the morning, though at midday, values decreased to half those of the control trees. Decreasing leaf water potential by osmotic adjustment to maintain gs and Amax under soil drying in treatment trees was considered to represent anisohydric behavior. These results suggest that D. aromatica may have high leaf adaptability to drought by regulating leaf water consumption and maintaining turgor pressure to improve its leaf water relations.

Matched MeSH terms: Borneo
Vertical variation in wood CO2 efflux is not uniformly related to height: measurement across various species and sizes of Bornean tropical rainforest trees

Katayama A, Kume T, Ichihashi R, Nakagawa M

Tree Physiol, 2019 06 01;39(6):1000-1008.
PMID: 30976804 DOI: 10.1093/treephys/tpz022

Limited knowledge about vertical variation in wood CO2 efflux (Rwood) is still a cause of uncertainty in Rwood estimates at individual and ecosystem scales. Although previous studies found higher Rwood in the canopy, they examined several tree species of similar size. In contrast, in the present study, we measured vertical variation in Rwood for 18 trees including 13 species, using a canopy crane for a more precise determination of the vertical variation in Rwood, for various species and sizes of trees in order to examine the factors affecting vertical variation in Rwood and thus, to better understand the effect of taking into account the vertical and inter-individual variation on estimates of Rwood at the individual scale. We did not find any clear pattern of vertical variation; Rwood increased significantly with measurement height for only one tree, while it decreased for two more trees, and was not significantly related with measurement height in 15 other trees. Canopy to breast height Rwood ratio was not related to diameter at breast height or crown ratio, which supposedly are factors affecting vertical variation in Rwood. On average, Rwood estimates at individual scale, considering inter-individual variation but ignoring vertical variation, were only 6% higher than estimates considering both forms of variation. However, estimates considering vertical variation, while ignoring inter-individual variation, were 13% higher than estimates considering both forms of variation. These results suggest that individual measurements at breast height are more important for estimating Rwood at the individual scale, and that any error in Rwood estimation at this scale, due to the absence of any more measurements along tree height, is really quite negligible. This study measured various species and sizes of trees, which may be attributed to no clear vertical variation because factors causing vertical variation can differ among species and sizes.

Matched MeSH terms: Borneo
Vertical variations in wood CO2 efflux for live emergent trees in a Bornean tropical rainforest

Katayama A, Kume T, Komatsu H, Ohashi M, Matsumoto K, Ichihashi R, et al.

Tree Physiol, 2014 May;34(5):503-12.
PMID: 24876294 DOI: 10.1093/treephys/tpu041

Difficult access to 40-m-tall emergent trees in tropical rainforests has resulted in a lack of data related to vertical variations in wood CO2 efflux, even though significant variations in wood CO2 efflux are an important source of errors when estimating whole-tree total wood CO2 efflux. This study aimed to clarify vertical variations in wood CO2 efflux for emergent trees and to document the impact of the variations on the whole-tree estimates of stem and branch CO2 efflux. First, we measured wood CO2 efflux and factors related to tree morphology and environment for seven live emergent trees of two dipterocarp species at four to seven heights of up to ∼ 40 m for each tree using ladders and a crane. No systematic tendencies in vertical variations were observed for all the trees. Wood CO2 efflux was not affected by stem and air temperature, stem diameter, stem height or stem growth. The ratios of wood CO2 efflux at the treetop to that at breast height were larger in emergent trees with relatively smaller diameters at breast height. Second, we compared whole-tree stem CO2 efflux estimates using vertical measurements with those based on solely breast height measurements. We found similar whole-tree stem CO2 efflux estimates regardless of the patterns of vertical variations in CO2 efflux because the surface area in the canopy, where wood CO2 efflux often differed from that at breast height, was very small compared with that at low stem heights, resulting in little effect of the vertical variations on the estimate. Additionally, whole-tree branch CO2 efflux estimates using measured wood CO2 efflux in the canopy were considerably different from those measured using only breast height measurements. Uncertainties in wood CO2 efflux in the canopy did not cause any bias in stem CO2 efflux scaling, but affected branch CO2 efflux.

Matched MeSH terms: Borneo

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links