Displaying publications 101 - 120 of 151 in total

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  1. Fulltext The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants
    Woodcock P, Edwards DP, Fayle TM, Newton RJ, Khen CV, Bottrell SH, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3256-64.
    PMID: 22006966 DOI: 10.1098/rstb.2011.0031
    South East Asia is widely regarded as a centre of threatened biodiversity owing to extensive logging and forest conversion to agriculture. In particular, forests degraded by repeated rounds of intensive logging are viewed as having little conservation value and are afforded meagre protection from conversion to oil palm. Here, we determine the biological value of such heavily degraded forests by comparing leaf-litter ant communities in unlogged (natural) and twice-logged forests in Sabah, Borneo. We accounted for impacts of logging on habitat heterogeneity by comparing species richness and composition at four nested spatial scales, and examining how species richness was partitioned across the landscape in each habitat. We found that twice-logged forest had fewer species occurrences, lower species richness at small spatial scales and altered species composition compared with natural forests. However, over 80 per cent of species found in unlogged forest were detected within twice-logged forest. Moreover, greater species turnover among sites in twice-logged forest resulted in identical species richness between habitats at the largest spatial scale. While two intensive logging cycles have negative impacts on ant communities, these degraded forests clearly provide important habitat for numerous species and preventing their conversion to oil palm and other crops should be a conservation priority.
    Matched MeSH terms: Population Density
  2. Transition of water demand and treatment plant overcapacity: a case study of the Seoul Metropolitan City, Korea
    Lee S, Park H
    Water Sci Technol, 2010;61(12):3129-40.
    PMID: 20555209 DOI: 10.2166/wst.2010.454
    This study deals with the overcapacity problem of water treatment plants in Korea, and mainly discusses status, causes, and engineering options. To this end, we first statistically analyze the recent trend of demand, revealing that the demands of small- and mid-size systems are still increasing while that of large-size systems is now decreasing. Since the existing approach to plan capacity implicitly assumes that demand will increase at a regular rate, we estimate excess capacities and system utilizations of large-size systems. From these results it is found that the large-size systems are suffering from serious overcapacity, thus necessitating that engineers make very difficult decisions given that systems are still expanding the capacities of plants due to a lack of awareness of the current demand trend. For other systems where there is a better understanding of the transition of demand, planners have ceased to expand plants or have closed down relatively old plants in efforts to reduce O&M costs. To address this problem, quick recognition of the transition of demand is being highlighted by the concepts of integrated resources management and cybernetics. Therefore, we examined how quickly the new trend of the Seoul case could be precisely recognized and appropriately addressed. Using the Bayesian parameter estimation method, we found that a new trend can be recognized six years after the transition of demand.
    Matched MeSH terms: Population Density
  3. Estimating the population density of the Asian tapir (Tapirus indicus) in a selectively logged forest in Peninsular Malaysia
    Rayan DM, Mohamad SW, Dorward L, Aziz SA, Clements GR, Christopher WCT, et al.
    Integr Zool, 2012 Dec;7(4):373-380.
    PMID: 23253368 DOI: 10.1111/j.1749-4877.2012.00321.x
    The endangered Asian tapir (Tapirus indicus) is threatened by large-scale habitat loss, forest fragmentation and increased hunting pressure. Conservation planning for this species, however, is hampered by a severe paucity of information on its ecology and population status. We present the first Asian tapir population density estimate from a camera trapping study targeting tigers in a selectively logged forest within Peninsular Malaysia using a spatially explicit capture-recapture maximum likelihood based framework. With a trap effort of 2496 nights, 17 individuals were identified corresponding to a density (standard error) estimate of 9.49 (2.55) adult tapirs/100 km(2) . Although our results include several caveats, we believe that our density estimate still serves as an important baseline to facilitate the monitoring of tapir population trends in Peninsular Malaysia. Our study also highlights the potential of extracting vital ecological and population information for other cryptic individually identifiable animals from tiger-centric studies, especially with the use of a spatially explicit capture-recapture maximum likelihood based framework.
    Matched MeSH terms: Population Density
  4. Fulltext Seasonal and Spatial Dynamics of the Primary Vector of Plasmodium knowlesi within a Major Transmission Focus in Sabah, Malaysia
    Wong ML, Chua TH, Leong CS, Khaw LT, Fornace K, Wan-Sulaiman WY, et al.
    PLoS Negl Trop Dis, 2015;9(10):e0004135.
    PMID: 26448052 DOI: 10.1371/journal.pntd.0004135
    BACKGROUND: The simian malaria parasite Plasmodium knowlesi is emerging as a public health problem in Southeast Asia, particularly in Malaysian Borneo where it now accounts for the greatest burden of malaria cases and deaths. Control is hindered by limited understanding of the ecology of potential vector species.

    METHODOLOGY/PRINCIPAL FINDINGS: We conducted a one year longitudinal study of P. knowlesi vectors in three sites within an endemic area of Sabah, Malaysia. All mosquitoes were captured using human landing catch. Anopheles mosquitoes were dissected to determine, oocyst, sporozoites and parous rate. Anopheles balabacensis is confirmed as the primary vector of. P. knowlesi (using nested PCR) in Sabah for the first time. Vector densities were significantly higher and more seasonally variable in the village than forest or small scale farming site. However An. balabacensis survival and P. knowlesi infection rates were highest in forest and small scale farm sites. Anopheles balabacensis mostly bites humans outdoors in the early evening between 1800 to 2000 hrs.

    CONCLUSIONS/SIGNIFICANCE: This study indicates transmission is unlikely to be prevented by bednets. This combined with its high vectorial capacity poses a threat to malaria elimination programmes within the region.

    Matched MeSH terms: Population Density
  5. The prevalence of Plasmodium falciparum and P. vivax in relation to Anopheles maculatus densities in a Malaysian village
    Rahman WA, Abu Hassan A, Adanan CR, Rashid MR
    Acta Trop, 1993 Dec;55(4):231-5.
    PMID: 8147279
    Blood from most of the residents of a remote village in northern peninsular Malaysia, bordering Thailand, was examined for malaria parasites monthly for 1 year. Plasmodium vivax was the commonest infection, but P. falciparum and mixed infections also occurred. Monthly collections of the malaria vector, Anopheles maculatus showed a positive correlation between mosquito densities and malaria positivity in the human population and a negative correlation with rainfall.
    Matched MeSH terms: Population Density
  6. Resource use of insect seed predators during general flowering and seeding events in a Bornean dipterocarp rain forest
    Nakagawa M, Itioka T, Momose K, Yumoto T, Komai F, Morimoto K, et al.
    Bull. Entomol. Res., 2003 Oct;93(5):455-66.
    PMID: 14658448
    Insect seed predators of 24 dipterocarp species (including the genera ot Dipterocarpus, Dryobalanops and Shorea) and five species belonging to the Moraceae, Myrtaceae, Celastraceae and Sapotaceae were investigated. In a tropical lowland dipterocarp forest in Sarawak, Malaysia, these trees produces seeds irregularly by intensely during general flowering and seeding events in 1996 and/or 1998. Dipterocarp seeds were preyed on by 51 insect species (11 families), which were roughly classified into three taxonomic groups: smaller moths (Trotricidae, Pyralidae, Crambidae, Immidae, Sesiidae, and Cosmopterigidae), scolytids (Scolydae) and weevils (Curdulionidae, Apionidae, Anthribidae, and Attelabidae). Although the host-specificity of invertebrate seed predators has been assumed to be high in tropical forests, it was found that the diet ranges of some insect predators were relatively wide and overlapped one another. Most seed predators that were collected in both study years changes their diets between general flowering and seeding events. The results of cluster analyses based on the number of adult of each predator species that emerged from 100 seeds of each tree species, suggested that the dominant species was not consistent, alternating between the two years.
    Matched MeSH terms: Population Density
  7. Fulltext Disease risk analysis in sea turtles: A baseline study to inform conservation efforts
    Mashkour N, Jones K, Kophamel S, Hipolito T, Ahasan S, Walker G, et al.
    PLoS One, 2020;15(10):e0230760.
    PMID: 33095793 DOI: 10.1371/journal.pone.0230760
    The impact of a range of different threats has resulted in the listing of six out of seven sea turtle species on the IUCN Red List of endangered species. Disease risk analysis (DRA) tools are designed to provide objective, repeatable and documented assessment of the disease risks for a population and measures to reduce these risks through management options. To the best of our knowledge, DRAs have not previously been published for sea turtles, although disease is reported to contribute to sea turtle population decline. Here, a comprehensive list of health hazards is provided for all seven species of sea turtles. The possible risk these hazards pose to the health of sea turtles were assessed and "One Health" aspects of interacting with sea turtles were also investigated. The risk assessment was undertaken in collaboration with more than 30 experts in the field including veterinarians, microbiologists, social scientists, epidemiologists and stakeholders, in the form of two international workshops and one local workshop. The general finding of the DRA was the distinct lack of knowledge regarding a link between the presence of pathogens and diseases manifestation in sea turtles. A higher rate of disease in immunocompromised individuals was repeatedly reported and a possible link between immunosuppression and environmental contaminants as a result of anthropogenic influences was suggested. Society based conservation initiatives and as a result the cultural and social aspect of interacting with sea turtles appeared to need more attention and research. A risk management workshop was carried out to acquire the insights of local policy makers about management options for the risks relevant to Queensland and the options were evaluated considering their feasibility and effectiveness. The sea turtle DRA presented here, is a structured guide for future risk assessments to be used in specific scenarios such as translocation and head-starting programs.
    Matched MeSH terms: Population Density
  8. Genetic Structure and Diversity Among Historic and Modern Populations of the Sumatran Rhinoceros (Dicerorhinus sumatrensis)
    Brandt JR, van Coeverden de Groot PJ, Witt KE, Engelbrektsson PK, Helgen KM, Malhi RS, et al.
    J Hered, 2018 06 27;109(5):553-565.
    PMID: 29684146 DOI: 10.1093/jhered/esy019
    The Sumatran rhinoceros (Dicerorhinus sumatrensis), once widespread across Southeast Asia, now consists of as few as 30 individuals within Sumatra and Borneo. To aid in conservation planning, we sequenced 218 bp of control region mitochondrial (mt) DNA, identifying 17 distinct mitochondrial haplotypes across modern (N = 13) and museum (N = 26) samples. Museum specimens from Laos and Myanmar had divergent mtDNA, consistent with the placement of western mainland rhinos into the distinct subspecies D. s. lasiotis (presumed extinct). Haplotypes from Bornean rhinos were highly diverse, but dissimilar from those of other regions, supporting the distinctiveness of the subspecies D. s. harrissoni. Rhinos from Sumatra and Peninsular Malaysia shared mtDNA haplotypes, consistent with their traditional placement into a single subspecies D. s sumatrensis. Modern samples of D. s. sumatrensis were genotyped at 18 microsatellite loci. Rhinos within Sumatra formed 2 sub-populations, likely separated by the Barisan Mountains, though with only modest genetic differentiation between them. There are so few remaining Sumatran rhinoceros that separate management strategies for subspecies or subpopulations may not be viable, while each surviving rhino pedigree is likely to retain alleles found in no other individuals. Given the low population size and low reproductive potential of Sumatran rhinos, rapid genetic erosion is inevitable, though an under-appreciated concern is the potential for fixation of harmful genetic variants. Both concerns underscore 2 overriding priorities for the species: 1) translocation of wild rhinos to ex situ facilities, and 2) collection and storage of gametes and cell lines from every surviving captive and wild individual.
    Matched MeSH terms: Population Density
  9. Fulltext Genetic diversity of Nile tilapia (Oreochromis niloticus) throughout West Africa
    Lind CE, Agyakwah SK, Attipoe FY, Nugent C, Crooijmans RPMA, Toguyeni A
    Sci Rep, 2019 11 14;9(1):16767.
    PMID: 31727970 DOI: 10.1038/s41598-019-53295-y
    Nile tilapia (Oreochromis niloticus) is a globally significant aquaculture species rapidly gaining status as a farmed commodity. In West Africa, wild Nile tilapia genetic resources are abundant yet knowledge of fine-scale population structure and patterns of natural genetic variation are limited. Coinciding with this is a burgeoning growth in tilapia aquaculture in Ghana and other countries within the region underpinned by locally available genetic resources. Using 192 single nucleotide polymorphism (SNP) markers this study conducted a genetic survey of Nile tilapia throughout West Africa, sampling 23 wild populations across eight countries (Benin, Burkina Faso, Côte d'Ivoire, Ghana, Togo, Mali, Gambia and Senegal), representing the major catchments of the Volta, Niger, Senegal and Gambia River basins. A pattern of isolation-by-distance and significant spatial genetic structure was identified throughout West Africa (Global FST = 0.144), which largely corresponds to major river basins and, to a lesser extent, sub-basins. Two populations from the Gambia River (Kudang and Walekounda), one from the western Niger River (Lake Sélingué) and one from the upper Red Volta River (Kongoussi) showed markedly lower levels of diversity and high genetic differentiation compared to all other populations, suggesting genetically isolated populations occurring across the region. Genetic structure within the Volta Basin did not always follow the pattern expected for sub-river basins. This study identifies clear genetic structuring and differentiation amongst West African Nile tilapia populations, which concur with broad patterns found in previous studies. In addition, we provide new evidence for fine-scale genetic structuring within the Volta Basin and previously unidentified genetic differences of populations in Gambia. The 192 SNP marker suite used in this study is a useful tool for differentiating tilapia populations and we recommend incorporating this marker suite into future population screening of O. niloticus. Our results form the basis of a solid platform for future research on wild tilapia genetic resources in West Africa, and the identification of potentially valuable germplasm for use in ongoing breeding programs for aquaculture.
    Matched MeSH terms: Population Density
  10. Fulltext Snapshot of antimicrobial stewardship programs in the hospitals of Pakistan: findings and implications
    Saleem Z, Hassali MA, Hashmi FK, Godman B, Ahmed Z
    Heliyon, 2019 Jul;5(7):e02159.
    PMID: 31384689 DOI: 10.1016/j.heliyon.2019.e02159
    Objective: We are unaware of the extent of antimicrobial stewardship programs (ASPs) among hospitals in Pakistan, which is a concern given the population size, high use of antibiotics across sectors and increasing antimicrobial resistance (AMR) rates. Consequently, we sought to address this by undertaking a comprehensive survey.

    Method: In this cross-sectional observational study in Punjab, an instrument of the measure was developed based on health care facility characteristics and ASPs after an extensive literature review. The questionnaire was circulated by mail or through drop off surveys to medical superintendents or directors/heads of pharmacy departments of hospitals.

    Results: Out of 254, a total of 137 hospitals fully completed the questionnaire - 11 primary, 65 secondary, 46 tertiary and 15 specialized hospitals. The use of antimicrobial prescribing guidelines (68.7%), provision of infectious diseases consultation services (66.4%), clinical pharmacy service (65.7%), use of drug and therapeutics committees to approve antimicrobial prescribing (65.5%), regular audit by doctors on antimicrobial prescribing (54.1%) and use of a restricted formulary for antimicrobial (50.4%) were the most common ASPs. However, most of these activities were only somewhat or moderately successful. Whereas, electronic antimicrobial prescribing approval systems (15.3%), using a sticker to notify prescribers regarding the need to obtain approval for the antimicrobial prescribed (16.1%) and participation in the national antimicrobial utilization surveillance program (19.7%) were only seen in a few hospitals.

    Conclusion: Study inferred that there are inadequate ASPs in the hospitals of Pakistan. A multidisciplinary approach, clinical leadership and availability of motivated and trained individuals are essential elements for the success of future ASPs.

    Matched MeSH terms: Population Density
  11. Fulltext Predictors of (in)efficiencies of Healthcare Expenditure Among the Leading Asian Economies - Comparison of OECD and Non-OECD Nations
    Jakovljevic M, Sugahara T, Timofeyev Y, Rancic N
    Risk Manag Healthc Policy, 2020;13:2261-2280.
    PMID: 33117004 DOI: 10.2147/RMHP.S266386
    Purpose: The goal of this study was to assess the effectiveness of healthcare spending among the leading Asian economies.

    Methods: We have selected a total of nine Asian nations, based on the strength of their economic output and long-term real GDP growth rates. The OECD members included Japan and the Republic of Korea, while the seven non-OECD nations were China, India, Indonesia, Malaysia, Pakistan, the Philippines, and Thailand. Healthcare systems efficiency was analyzed over the period 1996-2017. To assess the effectiveness of healthcare expenditure of each group of countries, the two-way fixed effects model (country- and year effects) was used.

    Results: Quality of governance and current health expenditure determine healthcare system performance. Population density and urbanization are positively associated with a healthy life expectancy in the non-OECD Asian countries. In this group, unsafe water drinking has a statistically negative effect on healthy life expectancy. Interestingly, only per capita consumption of carbohydrates is significantly linked with healthy life expectancy. In these non-OECD Asian countries, unsafe water drinking and per capita carbon dioxide emissions increase infant mortality. There is a strong negative association between GDP per capita and infant mortality in both sub-samples, although its impact is far larger in the OECD group. In Japan and South Korea, unemployment is negatively associated with infant mortality.

    Conclusion: Japan outperforms other countries from the sample in major healthcare performance indicators, while South Korea is ranked second. The only exception is per capita carbon dioxide emissions, which have maximal values in the Republic of Korea and Japan. Non-OECD nations' outcomes were led by China, as the largest economy. This group was characterized with substantial improvement in efficiency of health spending since the middle of the 1990s. Yet, progress was noted with remarkable heterogeneity within the group.

    Matched MeSH terms: Population Density
  12. Global status and conservation potential of reef sharks
    MacNeil MA, Chapman DD, Heupel M, Simpfendorfer CA, Heithaus M, Meekan M, et al.
    Nature, 2020 07;583(7818):801-806.
    PMID: 32699418 DOI: 10.1038/s41586-020-2519-y
    Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats3. Here we address this knowledge gap using data from more than 15,000 standardized baited remote underwater video stations that were deployed on 371 reefs in 58 nations to estimate the conservation status of reef sharks globally. Our results reveal the profound impact that fishing has had on reef shark populations: we observed no sharks on almost 20% of the surveyed reefs. Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population. However, opportunities for the conservation of reef sharks remain: shark sanctuaries, closed areas, catch limits and an absence of gillnets and longlines were associated with a substantially higher relative abundance of reef sharks. These results reveal several policy pathways for the restoration and management of reef shark populations, from direct top-down management of fishing to indirect improvement of governance conditions. Reef shark populations will only have a high chance of recovery by engaging key socio-economic aspects of tropical fisheries.
    Matched MeSH terms: Population Density
  13. Cold adaptation in the Asian tiger mosquito's native range precedes its invasion success in temperate regions
    Sherpa S, Blum MGB, Després L
    Evolution, 2019 09;73(9):1793-1808.
    PMID: 31313825 DOI: 10.1111/evo.13801
    Adaptation to environmental conditions within the native range of exotic species can condition the invasion success of these species outside their range. The striking success of the Asian tiger mosquito, Aedes albopictus, to invade temperate regions has been attributed to the winter survival of diapause eggs in cold environments. In this study, we evaluate genetic polymorphisms (SNPs) and wing morphometric variation among three biogeographical regions of the native range of A. albopictus. Reconstructed demographic histories of populations show an initial expansion in Southeast Asia and suggest that marine regression during late Pleistocene and climate warming after the last glacial period favored expansion of populations in southern and northern regions, respectively. Searching for genomic signatures of selection, we identified significantly differentiated SNPs among which several are located in or within 20 kb distance from candidate genes for cold adaptation. These genes involve cellular and metabolic processes and several of them have been shown to be differentially expressed under diapausing conditions. The three biogeographical regions also differ for wing size and shape, and wing size increases with latitude supporting Bergmann's rule. Adaptive genetic and morphometric variation observed along the climatic gradient of A. albopictus native range suggests that colonization of northern latitudes promoted adaptation to cold environments prior to its worldwide invasion.
    Matched MeSH terms: Population Density
  14. Fulltext Pre-extinction Demographic Stability and Genomic Signatures of Adaptation in the Woolly Rhinoceros
    Lord E, Dussex N, Kierczak M, Díez-Del-Molino D, Ryder OA, Stanton DWG, et al.
    Curr Biol, 2020 10 05;30(19):3871-3879.e7.
    PMID: 32795436 DOI: 10.1016/j.cub.2020.07.046
    Ancient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna. However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction. The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP). While humans and climate change have been proposed as potential causes of extinction [1-3], knowledge is limited on how the woolly rhinoceros was impacted by human arrival and climatic fluctuations [2]. Here, we use one complete nuclear genome and 14 mitogenomes to investigate the demographic history of woolly rhinoceros leading up to its extinction. Unlike other northern megafauna, the effective population size of woolly rhinoceros likely increased at 29.7 ka BP and subsequently remained stable until close to the species' extinction. Analysis of the nuclear genome from a ∼18.5-ka-old specimen did not indicate any increased inbreeding or reduced genetic diversity, suggesting that the population size remained steady for more than 13 ka following the arrival of humans [4]. The population contraction leading to extinction of the woolly rhinoceros may have thus been sudden and mostly driven by rapid warming in the Bølling-Allerød interstadial. Furthermore, we identify woolly rhinoceros-specific adaptations to arctic climate, similar to those of the woolly mammoth. This study highlights how species respond differently to climatic fluctuations and further illustrates the potential of palaeogenomics to study the evolutionary history of extinct species.
    Matched MeSH terms: Population Density
  15. Fulltext Breeding patterns of the JE vector Culex gelidus and its insect predators in rice cultivation areas of northern peninsular Malaysia
    Abu Hassan A, Hamady D, Tomomitsu S, Michael B, Jameel S L AS
    Trop Biomed, 2010 Dec;27(3):404-16.
    PMID: 21399580 MyJurnal
    Japanese encephalitis (JE) virus activity is an important cause of viral encephalitis in Southeast Asia. In Malaysia, JEV activity has been first detected in Culex gelidus in 1976. Since then, no study has fully addressed the seasonal dynamics of this mosquito. As irrigated rice production expands, the incidence of JEV vectors, particularly Cx. gelidus is expected to increase. We surveyed Penang Island to determine the breeding patterns of Cx. gelidus and their potential insect predators, in relation to habitat/niche and rice growing period. Six rice fields proper (RFP) and related drainage canals (DC) were visited through three cultivation cycles (CCs) over 17 months. Weekly visits were performed to each of the 36 sites and mosquito larvae and aquatic insects were sampled from RFP and DCs using dippers. Culex gelidus was abundant in RFP and almost absent in DCs. Its densities usually were high during the first and 3rd CC and when the RFs were in Fp, Pp and Gp. In DCs, the mosquito was abundant during Mp, e.g., 2nd CC. Predators, especially those belonging to the families Corixidae, Coenagrionidae and Dytiscidae, were more present in RFP. Predator numbers usually were high during the first CC; in some cases predator abundance peaked during other CCs, e.g., corixids and dysticids. In RFP, neither corixids nor coenagrionids showed any positive correlation with densities of Cx. gelidus. However, dytiscids' population peaked when the mosquito densities were on the rise. These observations suggest that Cx. gelidus is active during the period of rice cultivation. Operational vector control through bio-control or with insecticides near the end of the rice cultivation season in RFP may prove beneficial in reducing the density of Cx. gelidus, but also the amount of bio-agent or insecticide applied on riceland.
    Matched MeSH terms: Population Density
  16. Fulltext Preliminary study on the effectiveness of mosquito repelling lamp, E Da
    Chen CD, Azahari AH, Saadiyah I, Lee HL
    Trop Biomed, 2007 Dec;24(2):89-91.
    PMID: 18209714 MyJurnal
    Photon (light) technology has already been widely used in make-up, medical treatment etc, but repelling mosquitoes by photon technology is an innovation. The objective of this study was to determine the efficacy of a mosquito repelling lamp, E Da under indoor conditions. E Da lamp is a lamp coated with yellow luminous pigment on the inner part of the glass bulb of the lamp which is used to screen out the UV radiation, and when it is turned on, the yellow illuminating wavelength will drive the mosquitoes away. The tests were conducted inside 2 cabins measuring 8' X 8' X 20'. The mosquito population was estimated by using the Bare Leg Catch (BLC) techniques. For treated test, E Da lamp was placed indoor 2 - 3 meters away from a human bait. Another cabin without the lamp was used as untreated control. BLC was conducted in both sites simultaneously. The mosquitoes collected in this study were solely those of Culex quinquefasciatus and Aedes albopictus. There was an 91.34% reduction of Cx. quinquefasciatus population in the treated test compared with the untreated cabin during the 4 hours catches (p < 0.05). E Da mosquito repelling lamp used in this study exerted repellency effect against the mosquitoes especially Cx. quinquefasciatus.
    Matched MeSH terms: Population Density
  17. Fulltext Distribution and abundance of diurnal and nocturnal dipterous flies in the Federal Territory, Putrajaya
    Nazni WA, Nooraidah H, Jeffery J, Azahari AH, Mohd Noor I, Sadiyah I, et al.
    Trop Biomed, 2007 Dec;24(2):61-6.
    PMID: 18209709 MyJurnal
    A study of diurnal and nocturnal distribution of flies was conducted in Putrajaya. Six different ecological habitats were selected, namely: botanical garden, lake-area, administration building, wetland, jungle fringes and housing areas. Two different type of traps, cylinderical and rectangular in shape were used in the study. Baits used in these traps were yeast, sugar, salted fish, shrimp paste and fresh liver. Traps were placed at the sites throughout the diurnal and nocturnal periods. The time for sunrise and sunset was determined using a Geographical Positioning System gadget (GARMIN) at the sites. Both type of traps were equally effective in trapping flies. There was no significant difference between both types of traps in their ability to trap flies (p > 0.05). A total of 1,534 flies were collected and identified from both types of trap using the multiple baits and habitats. The collection consisted of 23 species of flies classified under 6 families. The highest number of flies were caught from the lake-area followed by botanical garden, administration building, housing areas, wetland and jungle fringes. The most dominant species was Chrysomya megacephala, followed by species of Sarcophagidae and Musca domestica. Diurnal period had more numbers of flies (81.55%) compared to the nocturnal periods (18.45%). Some species of flies were strictly diurnal, some exibited both diurnal and nocturnal activities while only one species was strictly nocturnal.
    Matched MeSH terms: Population Density
  18. Fulltext Dengue vector surveillance in urban residential and settlement areas in Selangor, Malaysia
    Chen CD, Benjamin S, Saranum MM, Chiang YF, Lee HL, Nazni WA, et al.
    Trop Biomed, 2005 Jun;22(1):39-43.
    PMID: 16880752
    Ovitrap surveillance was conducted in two urban residential areas (Taman Samudera Timur and Taman Samudera Selatan) and in a settlement area (Kampung Banjar), which is located 16 km from Kuala Lumpur city center, Malaysia. In Taman Samudera, dengue cases were reported monthly in 2003/2004. Thus, a study was initiated to determine the distribution and abundance of dengue vectors, Aedes aegypti and Ae. albopictus. The ovitrap surveillance indicated that Ae. aegypti and Ae. albopictus were present both indoors and outdoors. The residential sites had 73 - 79% of the ovitraps with just Ae. aegypti population and Kg. Banjar had 56% of the ovitraps with just Ae. aegypti. In the indoor and outdoor of the residential areas, together with the settlement area, the Ae. aegypti density was significantly more than Ae. albopictus (p < 0.05) by 3 - 50 folds. There was no significant difference in the larval numbers of Ae. aegypti between indoors and outdoors (p > 0.05), thus implicating that adult gravid female Ae. aegypti are present both indoors and outdoors and they do oviposit indoors and outdoors. Ae. aegypti can be incriminated as the principal dengue vector in the urban residential site, Taman Samudera and in the settlement area, Kg. Banjar.
    Matched MeSH terms: Population Density
  19. Comparison of Intrinsic Rate of Different House Fly Densities in a Simulated Condition: A Prediction for House Fly Population and Control Threshold
    Ong SQ, Ahmad H, Jaal Z, Rus A, Fadzlah FH
    J Med Entomol, 2017 Jan;54(1):24-29.
    PMID: 28082628 DOI: 10.1093/jme/tjw140
    Determining the control threshold for a pest is common prior to initiating a pest control program; however, previous studies related to the house fly control threshold for a poultry farm are insufficient for determining such a threshold. This study aimed to predict the population changes of house fly population by comparing the intrinsic rate of increase (rm) for different house fly densities in a simulated system. This study first defined the knee points of a known population growth curve as a control threshold by comparing the rm of five densities of house flies in a simulated condition. Later, to understand the interactions between the larval and adult populations, the correlation between larval and adult capacity rate (rc) was studied. The rm values of 300- and 500-fly densities were significantly higher compared with the rm values at densities of 50 and 100 flies. This result indicated their representative indices as candidates for a control threshold. The rc of larval and adult populations were negatively correlated with densities of fewer than 300 flies; this implicated adult populations with fewer than 300 flies as declining while the larval population was growing; therefore, control approaches should focus on the immature stages. The results in the present study suggest a control threshold for house fly populations. Future works should focus on calibrating the threshold indices in field conditions.
    Matched MeSH terms: Population Density
  20. Fulltext Sumatran tiger survival threatened by deforestation despite increasing densities in parks
    Luskin MS, Albert WR, Tobler MW
    Nat Commun, 2017 12 05;8(1):1783.
    PMID: 29208916 DOI: 10.1038/s41467-017-01656-4
    The continuing development of improved capture-recapture (CR) modeling techniques used to study apex predators has also limited robust temporal and cross-site analyses due to different methods employed. We develop an approach to standardize older non-spatial CR and newer spatial CR density estimates and examine trends for critically endangered Sumatran tigers (Panthera tigris sumatrae) using a meta-regression of 17 existing densities and new estimates from our own fieldwork. We find that tiger densities were 47% higher in primary versus degraded forests and, unexpectedly, increased 4.9% per yr from 1996 to 2014, likely indicating a recovery from earlier poaching. However, while tiger numbers may have temporarily risen, the total potential island-wide population declined by 16.6% from 2000 to 2012 due to forest loss and degradation and subpopulations are significantly more fragmented. Thus, despite increasing densities in smaller parks, we conclude that there are only two robust populations left with >30 breeding females, indicating Sumatran tigers still face a high risk of extinction unless deforestation can be controlled.
    Matched MeSH terms: Population Density
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