Displaying publications 61 - 80 of 151 in total

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  1. Hill JK, Gray MA, Khen CV, Benedick S, Tawatao N, Hamer KC
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3265-76.
    PMID: 22006967 DOI: 10.1098/rstb.2011.0050
    Large areas of tropical forest now exist as remnants scattered across agricultural landscapes, and so understanding the impacts of forest fragmentation is important for biodiversity conservation. We examined species richness and nestedness among tropical forest remnants in birds (meta-analysis of published studies) and insects (field data for fruit-feeding Lepidoptera (butterflies and moths) and ants). Species-area relationships were evident in all four taxa, and avian and insect assemblages in remnants typically were nested subsets of those in larger areas. Avian carnivores and nectarivores and predatory ants were more nested than other guilds, implying that the sequential loss of species was more predictable in these groups, and that fragmentation alters the trophic organization of communities. For butterflies, the ordering of fragments to achieve maximum nestedness was by fragment area, suggesting that differences among fragments were driven mainly by extinction. In contrast for moths, maximum nestedness was achieved by ordering species by wing length; species with longer wings (implying better dispersal) were more likely to occur at all sites, including low diversity sites, suggesting that differences among fragments were driven more strongly by colonization. Although all four taxa exhibited high levels of nestedness, patterns of species turnover were also idiosyncratic, and thus even species-poor sites contributed to landscape-scale biodiversity, particularly for insects.
    Matched MeSH terms: Population Density
  2. Jaal Z, MacDonald WW
    PMID: 1488703
    Collections of adult anopheline mosquitos were made from a cow-baited trap in nine coastal villages located along nearly 160km of northwest peninsular Malaysia. Two collections, separated by 1.5 to 6 months, were made at each site. Nearly 6,000 anophelines of 19 species were collected. The dominant species were Anopheles peditaeniatus. An. sinensis, An. subpictus and An. lesteri paraliae. Small numbers of the malaria vectors An. maculatus (at one site) and An. campestris (at four sites) were collected, but no An. sundaicus were recorded.
    Matched MeSH terms: Population Density
  3. 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
  4. Jayasuriya JE
    PMID: 12265642
    Matched MeSH terms: Population Density*
  5. Kabir MJ, Hassanzadeh-Rostami Z, Ashrafian Amiri H, Nasrollapour Shirvani SD, Keshavarzi A, Hosseini S
    Malays Fam Physician, 2019;14(3):28-36.
    PMID: 32175038
    Background and objective: A successful family physician program needs ongoing and full cooperation between people and the organizations in charge. Ensuring the satisfaction of family physicians through improvement of the underlying factors could motivate them to provide high-quality services. This study aimed to determine the family physicians' satisfaction level with the factors affecting the dynamism of the urban family physicians program in the Fars and Mazandaran provinces of Iran.

    Method: This cross-sectional study was carried out in urban areas in the Fars and Mazandaran provinces in 2016. The sample consisted of 143 and 96 family physicians, respectively, in Fars and Mazandaran provinces and was selected using the stratified random sampling method. Data were collected using a questionnaire and included both sociodemographic variables and factors assessing the family physicians' satisfaction levels. Each factor was scored based on a Likert scale from 0 to 5 points, and any satisfaction level higher than 3 out of 5 was equated with being satisfied.

    Results: The overall satisfaction levels among family physicians in Fars and Mazandaran provinces were 2.77±0.53 and 3.37±0.56, respectively, revealing a statistically significant difference between provinces (p<0.001). Moreover, the mean satisfaction scores for the performances of healthcare centers, insurance companies, specialists, healthcare workers, and the population covered were 2.78±0.1, 2.54±0.9, 2.52±0.8, 4.24±0.07, and 2.96±0.8, respectively. The family physicians' levels of satisfaction were significantly correlated with population size (p=0.02, r= -0.106), and willingness to stay in an urban family physician program (p<0.001, r= +0.398).

    Conclusion: This study revealed that family physicians exhibited a low level of satisfaction with the urban family physician program. Given the direct association between family physicians' satisfaction levels and retention in the program, it is expected that family physicians will no longer stay in the program, and it is likely to have subsequent executive problems.

    Matched MeSH terms: Population Density
  6. Khairuddin NL, Raghazli R, Sah SA, Shafie NJ, Azman NM
    Trop Life Sci Res, 2011 Dec;22(2):81-92.
    PMID: 24575219 MyJurnal
    A study of the population size of Bandicota bengalensis rats in three markets in Penang was conducted from April 2004 through May 2005. Taman Tun Sardon Market (TTS), Batu Lanchang Market (BTLG) and Bayan Lepas Market (BYNLP) were surveyed. Six sampling sessions were conducted in each market for four consecutive nights per session. The total captures of B. bengalensis in TTS, BTLG and BYNLP were 92%, 73% and 89% respectively. The total population of B. bengalensis in TTS was estimated as 265.4 (with a 95% confidence interval of 180.9-424.2). The total population at BTLG was estimated as 69.9 (with a 95% confidence interval of 35.5-148.9). At BYNLP, the total population was estimated as 134.7 (with a 95% confidence interval of 77.8-278.4). In general, adult male rats were captured most frequently at each site (55.19%), followed by adult females (31.69%), juvenile males (9.84%) and juvenile females (3.27%). The results showed that the number of rats captured at each site differed significantly according to sex ratio and maturity (χ(2) = 121.45, df = 3, p<0.01). Our results suggest that the population sizes found by the study may not represent the actual population size in each market owing to the low numbers of rats recaptured. This finding might have resulted from the variety of foods available in the markets.
    Matched MeSH terms: Population Density
  7. Khalili Samani N, Esa Y, Amin SM, Fatin Mohd Ikhsan N
    PeerJ, 2016;4:e1930.
    PMID: 27231645 DOI: 10.7717/peerj.1930
    Plotosus canius (Hamilton, 1822) is a significant marine species in Malaysia from nutritional and commercial perspectives. Despite numerous fundamental research on biological characteristics of P. canius, there are various concerns on the level of population differentiation, genomic structure, and the level of genetic variability among their populations due to deficiency of genetic-based studies. Deficiency on basic contexts such as stock identification, phylogenetic relationship and population genetic structure would negatively impact their sustainable conservation. Hence, this study was conducted to characterize the genetic structure of P. canius for the first time through the application of mitochondrial Cytochrome Oxidase I (COI) gene, cross amplification of Tandanus tandanus microsatellites, and a total of 117 collected specimens across five selected populations of Malaysia. The experimental results of the mitochondrial analysis revealed that the haplotype diversity and nucleotide diversity varied from 0.395-0.771 and 0.033-0.65 respectively. Moreover, the statistical analysis of microsatellites addressed a considerable heterozygote insufficiency in all populations, with average observed heterozygosity (Ho ) value of 0.2168, which was lower than the standard heterozygosity in marine populations (Ho = 0.79). This alongside the high Fis values estimation, high pairwise differentiation among populations and low within population variations are supposed to be associated with small sample size, and inbreeding system. Besides, the significant finding of this study was the sharing of common haplotype KR086940, which reflects a historical genetic connectivity between Peninsular Malaysia and Borneo populations due to the geological history of Southeast Asia during Pleistocene era. Demographic analyses showed that all populations were in an equilibrium state with no significant evidence of population expansion. To put it briefly, the current study has managed to provide an initial genomic database toward understanding of the genetic characterization, phylogenetic, molecular diversification and population structure in P. canius, and should be necessary highlighted for appropriate management and conservation of species. Further studies must be carried out involving more geographical and sampling sites, larger population size per site, and utilization of species specific microsatellites loci.
    Matched MeSH terms: Population Density
  8. Kok KY, Rajendran P
    PLoS One, 2016;11(3):e0150558.
    PMID: 26943630 DOI: 10.1371/journal.pone.0150558
    The differential evolution algorithm has been widely applied on unmanned aerial vehicle (UAV) path planning. At present, four random tuning parameters exist for differential evolution algorithm, namely, population size, differential weight, crossover, and generation number. These tuning parameters are required, together with user setting on path and computational cost weightage. However, the optimum settings of these tuning parameters vary according to application. Instead of trial and error, this paper presents an optimization method of differential evolution algorithm for tuning the parameters of UAV path planning. The parameters that this research focuses on are population size, differential weight, crossover, and generation number. The developed algorithm enables the user to simply define the weightage desired between the path and computational cost to converge with the minimum generation required based on user requirement. In conclusion, the proposed optimization of tuning parameters in differential evolution algorithm for UAV path planning expedites and improves the final output path and computational cost.
    Matched MeSH terms: Population Density
  9. Kondo T, Nishimura S, Tani N, Ng KK, Lee SL, Muhammad N, et al.
    Am J Bot, 2016 Nov;103(11):1912-1920.
    PMID: 27797714
    PREMISE OF THE STUDY: In tropical rainforests of Southeast Asia, a highly fecund thrips (Thrips spp.) responds rapidly to the mass flowering at multiple-year intervals characteristic of certain species such as the canopy tree studied here, Shorea acuminata, by feeding on flower resources. However, past DNA analyses of pollen adherent to thrips bodies revealed that the thrips promoted a very high level of self-pollination. Here, we identified the pollinator that contributes to cross-pollination and discuss ways that the pollination system has adapted to mass flowering.

    METHODS: By comparing the patterns of floral visitation and levels of genetic diversity in adherent pollen loads among floral visitors, we evaluated the contribution of each flower visitor to pollination.

    KEY RESULTS: The big-eyed bug, Geocoris sp., a major thrips predator, was an inadvertent pollinator, and importantly contributed to cross-pollination. The total outcross pollen adhering to thrips was approximately 30% that on the big-eyed bugs. Similarly, 63% of alleles examined in S. acuminata seeds and seedlings occurred in pollen adhering to big-eyed bugs; about 30% was shared with pollen from thrips.

    CONCLUSIONS: During mass flowering, big-eyed bugs likely travel among flowering S. acuminata trees, attracted by the abundant thrips. Floral visitation patterns of big-eyed bugs vs. other insects suggest that these bugs can maintain their population size between flowering by preying upon another thrips (Haplothrips sp.) that inhabits stipules of S. acuminata throughout the year and quickly respond to mass flowering. Thus, thrips and big-eyed bugs are essential components in the pollination of S. acuminata.

    Matched MeSH terms: Population Density
  10. Lananan F, Jusoh A, Ali N, Lam SS, Endut A
    Bioresour Technol, 2013 Aug;141:75-82.
    PMID: 23562179 DOI: 10.1016/j.biortech.2013.03.006
    A study was performed to determine the effect of Conway and f/2 media on the growth of microalgae genera. Genera of Chlorella sp., Dunaliella sp., Isochrysis sp., Chaetoceros sp., Pavlova sp. and Tetraselmis sp. were isolated from the South China Sea. During the cultivation period, the density of cells were determined using Syringe Liquid Sampler Particle Measuring System (SLS-PMS) that also generated the population distribution curve based on the size of the cells. The population of the microalgae genera is thought to consist of mother and daughter generations since these microalgae genera reproduce by releasing small non-motile reproductive cells (autospores). It was found that the reproduction of Tetraselmis sp., Dunaliella sp. and Pavlova sp. could be sustained longer in f/2 Medium. Higher cell density was achieved by genus Dunaliella, Chlorella and Isochrysis in Conway Medium. Different genera of microalgae had a preference for different types of cultivation media.
    Matched MeSH terms: Population Density
  11. Latif MT, Dominick D, Ahamad F, Ahamad NS, Khan MF, Juneng L, et al.
    Sci Total Environ, 2016 Dec 15;573:494-504.
    PMID: 27572541 DOI: 10.1016/j.scitotenv.2016.08.121
    Malaysian Borneo has a lower population density and is an area known for its lush rainforests. However, changes in pollutant profiles are expected due to increasing urbanisation and commercial-industrial activities. This study aims to determine the variation of surface O3concentration recorded at seven selected stations in Malaysian Borneo. Hourly surface O3data covering the period 2002 to 2013, obtained from the Malaysian Department of Environment (DOE), were analysed using statistical methods. The results show that the concentrations of O3recorded in Malaysian Borneo during the study period were below the maximum Malaysian Air Quality Standard of 100ppbv. The hourly average and maximum O3concentrations of 31 and 92ppbv reported at Bintulu (S3) respectively were the highest among the O3concentrations recorded at the sampling stations. Further investigation on O3precursors show that sampling sites located near to local petrochemical industrial activities, such as Bintulu (S3) and Miri (S4), have higher NO2/NO ratios (between 3.21 and 5.67) compared to other stations. The normalised O3values recorded at all stations were higher during the weekend compared to weekdays (unlike its precursors) which suggests the influence of O3titration by NO during weekdays. The results also show that there are distinct seasonal variations in O3across Borneo. High surface O3concentrations were usually observed between August and September at all stations with the exception of station S7 on the east coast. Majority of the stations (except S1 and S6) have recorded increasing averaged maximum concentrations of surface O3over the analysed years. Increasing trends of NO2and decreasing trends of NO influence the yearly averaged maximum of O3especially at S3. This study also shows that variations of meteorological factors such as wind speed and direction, humidity and temperature influence the concentration of surface O3.
    Matched MeSH terms: Population Density
  12. Lau YY, How KY, Yin WF, Chan KG
    PeerJ, 2020;8:e10068.
    PMID: 33150063 DOI: 10.7717/peerj.10068
    Over the past decades, Enterobacter spp. have been identified as challenging and important pathogens. The emergence of multidrug-resistant Enterobacteria especially those that produce Klebsiella pneumoniae carbapenemase has been a very worrying health crisis. Although efforts have been made to unravel the complex mechanisms that contribute to the pathogenicity of different Enterobacter spp., there is very little information associated with AHL-type QS mechanism in Enterobacter spp. Signaling via N-acyl homoserine lactone (AHL) is the most common quorum sensing (QS) mechanism utilized by Proteobacteria. A typical AHL-based QS system involves two key players: a luxI gene homolog to synthesize AHLs and a luxR gene homolog, an AHL-dependent transcriptional regulator. These signaling molecules enable inter-species and intra-species interaction in response to external stimuli according to population density. In our recent study, we reported the genome of AHL-producing bacterium, Enterobacter asburiae strain L1. Whole genome sequencing and in silico analysis revealed the presence of a pair of luxI/R genes responsible for AHL-type QS, designated as easI/R, in strain L1. In a QS system, a LuxR transcriptional protein detects and responds to the concentration of a specific AHL controlling gene expression. In E. asburiae strain L1, EasR protein binds to its cognate AHLs, N-butanoyl homoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL), modulating the expression of targeted genes. In this current work, we have cloned the 693 bp luxR homolog of strain L1 for further characterization. The functionality and specificity of EasR protein in response to different AHL signaling molecules to activate gene transcription were tested and validated with β-galactosidase assays. Higher β-galactosidase activities were detected for cells harboring EasR, indicating EasR is a functional transcriptional regulator. This is the first report documenting the cloning and characterization of transcriptional regulator, luxR homolog of E. asburiae.
    Matched MeSH terms: Population Density
  13. Lee CC, Neoh KB, Lee CY
    J Econ Entomol, 2014 12;107(6):2154-62.
    PMID: 26470081 DOI: 10.1603/EC14193
    The efficacy of chitin synthesis inhibitors (CSIs) against fungus-growing termites is known to vary. In this study, 0.1% chlorfluazuron (CFZ) cellulose bait was tested against medium and large field colonies of Macrotermes gilvus (Hagen). The termite mounds were dissected to determine the health of the colony. Individual termites (i.e., workers and larvae) and fungus combs were subjected to gas chromatography-mass spectrometry (GC-MS) analysis to detect the presence of CFZ. In this study, 540.0 ± 25.8 g (or equivalent to 540.0 ± 25.8 mg active ingredient) and 680.0 ± 49.0 g (680.0 ± 49.0 mg active ingredient) of bait matrix were removed by the medium- and large-sized colonies, respectively, after baiting. All treated medium-sized colonies were moribund. The dead termites were scattered in the mound, larvae were absent, population size had decreased by 90%, and the queens appeared unhealthy. In contrast, no or limited effects were found in large-sized colonies. Only trace amounts of CFZ were detected in workers, larvae, and fungus combs, and the population of large-sized colonies had declined by only up to 40%. This might be owing to the presence of large amount of basidiomycete fungus and a drastic decrease of CFZ content per unit fungus comb (a main food source of larvae) in the large-sized colonies, and hence reduced the toxic effect and longer time is required to accumulate the lethal dose in larvae. Nevertheless, we do not deny the possibility of CSI bait eliminating or suppressing the higher termite if the test colonies could pick up adequate lethal dose by installing more bait stations and prolonging the baiting period.
    Matched MeSH terms: Population Density
  14. Lee CC, Lee CY
    J Econ Entomol, 2015 Jun;108(3):1243-50.
    PMID: 26470252 DOI: 10.1093/jee/tov112
    The optimum maintenance conditions of the fungus-growing termite, Macrotermes gilvus (Hagen) (Blattodea: Termitidae), in the laboratory were studied. Termites were kept on a matrix of moist sand and with fungus comb as food. The survival of groups of termites was measured when maintained at different population densities by changing group size and container volume. Larger groups (≥0.6 g) were more vigorous and had significant higher survival rates than smaller groups (≤0.3 g). The population density for optimal survival of M. gilvus is 0.0025 g per container volume (ml) or 0.0169 g per matrix volume (cm(3)), i.e., 1.2 g of termites kept in a 480-ml container filled with 71 cm3 of sand. In termite groups of smaller size (i.e., 0.3 g) or groups maintained in smaller container (i.e., 100 ml) the fungus comb was overgrown with Xylaria spp., and subsequently all termites died within the study period. The insufficient number of workers for regulating the growth of unwanted fungi other than Termitomyces spp. in the fungus comb is the most likely reason. Unlike some other mound-building termite species, M. gilvus showed satisfactory survival when maintained in non-nutritious matrix (i.e., sand). There was no significant difference in the survival rate between different colonies of M. gilvus (n=5), with survival in the range of 78.5-84.4% after 4 wk. Advances in the maintenance of Macrotermes will enable researchers to study with more biological relevance many aspects of the biology, behavior, and management of this species.
    Matched MeSH terms: Population Density
  15. 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
  16. Lee SL, Ng KK, Saw LG, Norwati A, Salwana MH, Lee CT, et al.
    Am J Bot, 2002 Mar;89(3):447-59.
    PMID: 21665641 DOI: 10.3732/ajb.89.3.447
    A field survey of Virgin Jungle Reserve (VJR) compartments in Peninsular Malaysia allowed us to identify six populations of Intsia palembanica for this study. These were Pasoh Forest Reserve (FR) (Pasoh), Sungai Lalang FR (Lalang), Bukit Lagong FR (Lagong), Bubu FR (Bubu), Bukit Kinta FR (Kinta), and Bukit Perangin FR (Perangin). About 40 adult individuals were sampled in each population. In addition, progeny arrays were collected from nine mother plants at Lagong for a mating system study. A total of nine allozymes, encoded by 14 putative gene loci, were consistently resolved in I. palembanica. The mating system study showed that the species exhibited a mixed-mating system, with multilocus outcrossing rate of 0.766. The levels of diversity were comparably high (mean number of alleles per polymorphic locus = 2.4, mean effective number of alleles per polymorphic locus = 1.64, and mean expected heterozygosity (H(e)) = 0.242), and the majority of the diversity was partitioned within population (G(ST) = 0.040 and F(ST) = 0.048). Significant levels of inbreeding were detected in Bubu and Perangin. Probability tests of recent effective population size reduction using the Infinite Allele Model showed the occurrence of genetic bottlenecks on Lalang and Kinta. Two genetically unique populations (Pasoh and Perangin) were inferred using jackknife analysis. By using the neutral mutation rates, effective population size (N(e)) to maintain the H(e) was 80-800 000 individuals. A simulation study based on pooled samples, however, circumscribed the N(e) to 200 and 210 individuals. Implications of the study for managing the species and the VJRs are discussed.
    Matched MeSH terms: Population Density
  17. Leong SC, Kueh RJ
    ScientificWorldJournal, 2011;11:2330-8.
    PMID: 22203789 DOI: 10.1100/2011/753484
    Seasonal population of the fruit-piercing moths Eudocima spp. was monitored throughout the citrus growing seasons in a citrus orchard and in site adjacent to secondary forest from July 2007 to June 2009. The moth was detected practically throughout the year with activity lowest during the wet months (September-February) when fruits are still available and while highest during the dry months (May-June) which also coincided with the main fruiting season. The effects of an nC24 horticultural mineral oil (HMO) on the citrus fruit damage caused by fruit-piecing moths was also determined. The percent fruit damage was significantly lowest (P≤0.05) in HMO-treated plots (8.4), followed by Dimethoate-treated plots (11.6) and untreated plots (22.5). However, there was no significant difference between HMO and Dimethoate treated plots indicating HMO is effective in reducing percent fruit damage.
    Matched MeSH terms: Population Density
  18. Lim KW, Sit NW, Norzahira R, Sing KW, Wong HM, Chew HS, et al.
    Trop Biomed, 2010 Aug;27(2):185-92.
    PMID: 20962714 MyJurnal
    A year-long ovitrap surveillance was conducted between November 2007 and October 2008 in two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) within the Malaysian island of Pulau Ketam. Eighty standard ovitraps were placed indoors and outdoors of randomly selected houses/locations. Results demonstrated an endemic baseline Aedes population throughout the year without weekly large fluctuations. Kampung Pulau Ketam has high Aedes aegypti and Aedes albopictus population, but only Ae. aegypti was found in Kampung Sungai Lima. Aedes aegypti showed no preference for ovitraps placed indoor versus outdoor. However, as expected, significantly more outdoor ovitraps were positive for Ae. albopictus (p<0.05). Trends in Ae. albopictus and Ae. aegypti populations mirrored each other suggesting that common factors influenced these two populations.
    Matched MeSH terms: Population Density
  19. Lim, Chai Ling, Usman Bala, Leong, Melody Pui-Yee, Johnson Stanslas, Rajesh Ramasamy, Ling, King-Hwa, et al.
    MyJurnal
    Down syndrome (DS) is a genetic condition resulting from triplication of human chromosome (HSA)21. Besides intellectual disability, DS is frequently associated with hypotonia. Satellite cells are the resident cells that provides robust and remarkable regenerative capacity to the skeletal muscles, and its population size has been reported to be disease-associated. However, little is known about the population size of satellite cells in DS and the association of its intrinsic cellular functionality and hypotonia seen in DS. Here, we studied the Ts1Cje mouse, a DS murine model displays the muscle weakness characteristic. Satellite cell populations were immunostained with Pax7 and myonuclei numbers in the Ts1Cje extensor digitorum longus muscle were assessed. Their cellular function was further determined via in vitro assay in high-serum conditioned medium. Subsequently, the in vitro self-renewal, proliferative, and differentiation activities of these myogenic precursor cells were assessed after 24, 48, and 72h using Pax7, MyoD, and Ki67 immunomarkers. Our results showed that the population and functionality of Ts1Cje satellite cell did not differ significantly when compared to the wildtype cells isolated from disomic littermates. In conclusion, our findings indicated that intrinsic cellular functionality of the satellite cells, do not contribute to muscle weakness in Ts1Cje mouse.
    Matched MeSH terms: Population Density
  20. 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
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