Displaying publications 81 - 100 of 317 in total

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  1. Mathematical modeling and analysis of anemia during pregnancy and postpartum
    Mat Daud AA, Toh CQ, Saidun S
    Theory Biosci, 2021 Feb;140(1):87-95.
    PMID: 33590451 DOI: 10.1007/s12064-020-00334-2
    Anemia is a significant public health problem worldwide especially among pregnant women in low- and middle-income countries. In this study, a mathematical model of the population dynamics of anemia during pregnancy and postpartum is constructed. In the modeling process, four independent variables have been considered: (1) the numbers of nonpregnant nonanemic women, (2) anemic nonpregnant women, (3) anemic pregnant or postpartum women and (4) anemic pregnant or postpartum women with complications. The mathematical model is governed by a system of first-order ordinary differential equations. The stability analysis of the model is conducted using Routh-Hurwitz criteria. There is one nonnegative equilibrium point which is asymptotically stable. The equilibrium point obtained indicates the influential parameters that can be controlled to minimize the number of patients at each stage. The proposed model can be employed to forecast the future incidence and prevalence of the disease and appraise intervention programs.
    Matched MeSH terms: Population Dynamics
  2. Dynamical behaviors and optimal harvesting of an intraguild prey-predator fishery model with Michaelis-Menten type predator harvesting
    Ang TK, Safuan HM
    Biosystems, 2021 Apr;202:104357.
    PMID: 33486091 DOI: 10.1016/j.biosystems.2021.104357
    The present paper discusses the dynamics and optimal harvesting of an intraguild prey-predator fishery model by incorporating the nonlinear Michaelis-Menten type of harvesting in predator. To our knowledge, there is limited literature working on Michaelis-Menten type of harvesting in a three species intraguild model with variable carrying capacity. The carrying capacity is proportional to the density of biotic resource. The existence of the possible equilibria has been studied along with the stability criteria. We consider the impact of predator fish harvesting as the bifurcation parameter to analyze the long time behavior of the proposed system. From the economic perspective, bionomic equilibrium of the system is studied and optimal harvesting policy is derived with the assistance of Pontryagin Maximum Principle. Finally, numerical results are presented to verify our analytical results. It is shown that in the bifurcation diagrams, the system can exhibit transcritical and Hopf bifurcations in the neighborhood of coexistence equilibrium at low and relatively high level of predator harvesting respectively. Interestingly, the system enters to a bistable region where both the coexistence and predator-free equilibria can be stable depending on the initial values. This bistable behavior might be novel to the existing literature that studied intraguild models with variable carrying capacity. The objective of this study is to derive the optimal threshold for the predator harvesting that gives maximum financial profit while sustaining the fishery resources.
    Matched MeSH terms: Population Dynamics*
  3. Fulltext Biodiversity, seasonal abundance, and distribution of blackflies (Diptera: Simuliidae) in six different regions of Thailand
    Srisuka W, Takaoka H, Otsuka Y, Fukuda M, Thongsahuan S, Taai K, et al.
    Parasit Vectors, 2017 Nov 21;10(1):574.
    PMID: 29157269 DOI: 10.1186/s13071-017-2492-y
    BACKGROUND: Blackflies are an important medical and veterinary group of small blood-sucking insects. Ninety-three blackfly species have been reported in Thailand. However, information on their biodiversity and population dynamics in each region is lacking. The main aim of this study was to assess the regional biodiversity, seasonal abundance and distribution of blackflies in six eco-geographically different regions in the country.

    METHODS: Blackfly larvae and pupae were sampled monthly from 58 sites between May 2011 and April 2013. Diversity parameters, seasonal abundance, regional distribution and frequency of species occurrence in stream sites were analyzed.

    RESULTS: A total of 19,456 mature larvae representing 57 species, and belonging to six subgenera in the genus Simulium Latreille (s.l.), were found. The five predominant taxa were S. fenestratum (8.6%), the S. asakoae complex (8.3%), S. nakhonense (7.5%), the S. siamense complex (7.4%) and the S. doipuiense complex (6.7%). The most frequent taxa at all sites were the S. asakoae complex (84.5%), followed by S. fenestratum (82.8%), the S. siamense complex (75.9%), S. decuplum (60.3%), S. nakhonense (58.6%) and the S. tani complex (48.3%). The richness of regional species was highest (40 species) in the north and predominated in the cold season. However, blackflies in the south predominated during the hot season. The highest numbers of blackflies collected from central, northeastern, eastern and western regions of the country were observed in the rainy season. Overall, the mean number of blackflies collected across the six regions during the rainy and cold season had no statistically significant difference, but it differed significantly in the hot season.

    CONCLUSIONS: Blackflies in Thailand were surveyed in all three seasons across six geographical regions. These findings demonstrated that blackfly communities at each stream site varied with seasonality, and the regional relative abundance of blackflies differed markedly in the hot season. It was also found that the occurrence and distribution of blackflies in each region were associated strongly with elevation.

    Matched MeSH terms: Population Dynamics
  4. Mortality trends of young children in developing countries
    Rutstein SO
    IPPF Med Bull, 1983 Dec;17(6):2-4.
    PMID: 12279694
    Matched MeSH terms: Population Dynamics
  5. Fulltext Sex preference for children in Thailand and some other South-East Asian countries
    Wongboonsin K, Ruffolo VP
    Asia Pac Popul J, 1995 Sep;10(3):43-62.
    PMID: 12290694
    Matched MeSH terms: Population Dynamics
  6. Malaysia family-planning centers strive to maintain gains won in 15-year period
    Roemer R
    Med Trib Med News, 1968 Sep 12;9(74):1.
    PMID: 12229348
    PIP: Family planning in Malaysia is discussed. Family planning began in Malaysia about 15 years ago through the efforts of voluntary family Planning Associations in the various Malay states. In 1966 the Malaysian Parliament passed the National Family Planning Act setting up the National FAmily Planning Board to formulate policies and methods for the promotion and spread of family planning knowledge and practice on the grounds of health of mothers and children and welfare of the family. In 1967, the board set a target of 40,000 new acceptors of family planning and 90% of the target was reached. This represents 3% of the child-bearing married women aged 15-49. The target for 1968 of 65,000 new acceptors is being achieved. A survey of acceptors is to be carried out from December 1968 to April 1969 to ascertain how many women who accepted family planning continue to practice it. Malaysia's crude birth rate declined from 46.2 in 1957 to 37.3 in 1966 before the government program was instituted. Abortion attempts have been frequent. The main method of contraception used is oral contraceptives. According to a 1957 survey, 31% of the married women in the metropolitan areas and 2% of rural women were using contraception. Presently, in Malaysia there is a need to: 1) train personnel to provide services, 2) inform and motivate families to accept family planning, 3) continue a broad educational program, 4) reform Malaysia's antiquated abortion law, and 5) integrate family planning services more fully into the general health services of the country.
    Matched MeSH terms: Population Dynamics
  7. Loxodonta Localizer: A Software Tool for Inferring the Provenance of African Elephants and Their Ivory Using Mitochondrial DNA
    Zhao K, Ishida Y, Green CE, Davidson AG, Sitam FAT, Donnelly CL, et al.
    J Hered, 2019 12 17;110(7):761-768.
    PMID: 31674643 DOI: 10.1093/jhered/esz058
    Illegal hunting is a major threat to the elephants of Africa, with more elephants killed by poachers than die from natural causes. DNA from tusks has been used to infer the source populations for confiscated ivory, relying on nuclear genetic markers. However, mitochondrial DNA (mtDNA) sequences can also provide information on the geographic origins of elephants due to female elephant philopatry. Here, we introduce the Loxodonta Localizer (LL; www.loxodontalocalizer.org), an interactive software tool that uses a database of mtDNA sequences compiled from previously published studies to provide information on the potential provenance of confiscated ivory. A 316 bp control region sequence, which can be readily generated from DNA extracted from ivory, is used as a query. The software generates a listing of haplotypes reported among 1917 African elephants in 24 range countries, sorted in order of similarity to the query sequence. The African locations from which haplotype sequences have been previously reported are shown on a map. We demonstrate examples of haplotypes reported from only a single locality or country, examine the utility of the program in identifying elephants from countries with varying degrees of sampling, and analyze batches of confiscated ivory. The LL allows for the source of confiscated ivory to be assessed within days, using widely available molecular methods that do not depend on a particular platform or laboratory. The program enables identification of potential regions or localities from which elephants are being poached, with capacity for rapid identification of populations newly or consistently targeted by poachers.
    Matched MeSH terms: Population Dynamics
  8. Single, rapid coastal settlement of Asia revealed by analysis of complete mitochondrial genomes
    Macaulay V, Hill C, Achilli A, Rengo C, Clarke D, Meehan W, et al.
    Science, 2005 May 13;308(5724):1034-6.
    PMID: 15890885
    A recent dispersal of modern humans out of Africa is now widely accepted, but the routes taken across Eurasia are still disputed. We show that mitochondrial DNA variation in isolated "relict" populations in southeast Asia supports the view that there was only a single dispersal from Africa, most likely via a southern coastal route, through India and onward into southeast Asia and Australasia. There was an early offshoot, leading ultimately to the settlement of the Near East and Europe, but the main dispersal from India to Australia approximately 65,000 years ago was rapid, most likely taking only a few thousand years.
    Matched MeSH terms: Population Dynamics*
  9. Fulltext Island Biogeography Revisited: Museomics Reveals Affinities of Shelf Island Birds Determined by Bathymetry and Paleo-Rivers, Not by Distance to Mainland
    Garg KM, Chattopadhyay B, Cros E, Tomassi S, Benedick S, Edwards DP, et al.
    Mol Biol Evol, 2022 Jan 07;39(1).
    PMID: 34893875 DOI: 10.1093/molbev/msab340
    Island biogeography is one of the most powerful subdisciplines of ecology: its mathematical predictions that island size and distance to mainland determine diversity have withstood the test of time. A key question is whether these predictions follow at a population-genomic level. Using rigorous ancient-DNA protocols, we retrieved approximately 1,000 genomic markers from approximately 100 historic specimens of two Southeast Asian songbird complexes from across the Sunda Shelf archipelago collected 1893-1957. We show that the genetic affinities of populations on small shelf islands defy the predictions of geographic distance and appear governed by Earth-historic factors including the position of terrestrial barriers (paleo-rivers) and persistence of corridors (Quaternary land bridges). Our analyses suggest that classic island-biogeographic predictors may not hold well for population-genomic dynamics on the thousands of shelf islands across the globe, which are exposed to dynamic changes in land distribution during Quaternary climate change.
    Matched MeSH terms: Population Dynamics
  10. Research and policy guidelines from the World Fertility Survey in Asia and the Pacific
    Rele JR
    Asian Pac Popul Programme News, 1979;8(4):10-2.
    PMID: 12261702
    Matched MeSH terms: Population Dynamics
  11. Fulltext The rural bite in population pyramids: what are the implications for responsiveness of health systems in middle income countries?
    Jahan N, Allotey P, Arunachalam D, Yasin S, Soyiri IN, Davey TM, et al.
    BMC Public Health, 2014;14 Suppl 2:S8.
    PMID: 25081203 DOI: 10.1186/1471-2458-14-S2-S8
    Health services can only be responsive if they are designed to service the needs of the population at hand. In many low and middle income countries, the rate of urbanisation can leave the profile of the rural population quite different from the urban population. As a consequence, the kinds of services required for an urban population may be quite different from that required for a rural population. This is examined using data from the South East Asia Community Observatory in rural Malaysia and contrasting it with the national Malaysia population profile.
    Matched MeSH terms: Population Dynamics*
  12. Monitoring tigers with confidence
    Linkie M, Guillera-Arroita G, Smith J, Rayan DM
    Integr Zool, 2010 Dec;5(4):342-350.
    PMID: 21392352 DOI: 10.1111/j.1749-4877.2010.00215.x
    With only 5% of the world's wild tigers (Panthera tigris Linnaeus, 1758) remaining since the last century, conservationists urgently need to know whether or not the management strategies currently being employed are effectively protecting these tigers. This knowledge is contingent on the ability to reliably monitor tiger populations, or subsets, over space and time. In the this paper, we focus on the 2 seminal methodologies (camera trap and occupancy surveys) that have enabled the monitoring of tiger populations with greater confidence. Specifically, we: (i) describe their statistical theory and application in the field; (ii) discuss issues associated with their survey designs and state variable modeling; and, (iii) discuss their future directions. These methods have had an unprecedented influence on increasing statistical rigor within tiger surveys and, also, surveys of other carnivore species. Nevertheless, only 2 published camera trap studies have gone beyond single baseline assessments and actually monitored population trends. For low density tiger populations (e.g. <1 adult tiger/100 km(2)) obtaining sufficient precision for state variable estimates from camera trapping remains a challenge because of insufficient detection probabilities and/or sample sizes. Occupancy surveys have overcome this problem by redefining the sampling unit (e.g. grid cells and not individual tigers). Current research is focusing on developing spatially explicit capture-mark-recapture models and estimating abundance indices from landscape-scale occupancy surveys, as well as the use of genetic information for identifying and monitoring tigers. The widespread application of these monitoring methods in the field now enables complementary studies on the impact of the different threats to tiger populations and their response to varying management intervention.
    Matched MeSH terms: Population Dynamics
  13. Fulltext Three decades of breast-feeding trends in Singapore
    Chua S, Viegas OA, Ratnam SS
    Asia Pac Popul J, 1990 Mar;5(1):125-34.
    PMID: 12283342
    Matched MeSH terms: Population Dynamics
  14. Fulltext Comparative study of understorey birds diversity inhabiting lowland rainforest virgin jungle reserve and regenerated forest
    Nor Hashim E, Ramli R
    ScientificWorldJournal, 2013;2013:676507.
    PMID: 24453888 DOI: 10.1155/2013/676507
    A comparative study of understorey birds inhabiting different habitats, that is, virgin jungle reserve (VJR) and regenerated forest (RF), was conducted in Ulu Gombak Forest Reserve and Selangor and Triang Forest Reserve, Negeri Sembilan, Peninsular Malaysia. The objective of this study was to assess the diversity of understorey birds in both habitats and the effects of forest regeneration on the understorey bird community. The mist-netting method was used to capture understorey birds inhabiting both habitats in both locations. Species composition and feeding guild indicated that understorey bird populations were similar in the two habitats. However, the number of secondary forest species such as Little spiderhunter (Arachnothera longirostra) in VJR is increasing due to its proximity to RF. This study discovered that RFs in both study areas are not yet fully recovered. However, based on the range of species discovered, the RFs have conservation value and should be maintained because they harbour important forest species such as babblers and flycatchers. The assessment of the community structure of understorey birds in VJR and RF is important for forest management and conservation, especially where both habitats are intact.
    Matched MeSH terms: Population Dynamics
  15. Effects of logging and recovery process on avian richness and diversity in hill dipterocarp tropical rainforest-Malaysia
    Husin MZ, Rajpar MN
    J Environ Biol, 2015 Jan;36 Spec No:121-7.
    PMID: 26591891
    The effects of logging and recovery process on avian richness and diversity was compared in recently logged and thirty year post-harvested hill dipterocarp tropical rainforest, using mist-netting method. Atotal of 803 bird individuals representing 86 bird species and 29 families (i.e., 37.90% from recently logged forest and 62.10% from thirty year post-harvested forest) were captured from October 2010 to September, 2012. Twenty one bird species were commonly captured from both types of forests, 37 bird species were caught only in thirty year post-harvested forest and 28 bird species were caught only from recently logged forest. Arachnothera longirostra--Little Spiderhunter, Malacopteron magnum--Rufous-crowned Babbler, Alophoixus phaeocephalus -Yellow-bellied Bulbul and Meiglyptes tukki--Buff-necked Woodpecker were the most abundant four bird species in the thirty year post-harvested forest. On the contrary, seven bird species, i.e., Trichastoma rostratum - White-chested Babbler, Lacedo pulchella - Banded Kingfisher, Picus miniaceus--Banded Woodpecker, Enicurus ruficapillus - Chestnut-naped Forktail, Anthreptes simplex--Plain Sunbird, Muscicapella hodgsoni--Pygmy Blue Flycatcher and Otus rufescens--Reddish Scope Owl were considered as the rarest (i.e., each represented only 0.12%). Likewise, A. longirostra, Pycnonotus eythropthalmos - Spectacled Bulbul, P. simplex--Cream-vented Bulbul and Merops viridis--Blue-throated Bee-eater were the most dominant and Copsychus malabaricus--White-rumped Shama Eurylaimus javanicus--Banded Broadbill /xos malaccensis - Streaked Bulbul and Harpactes diardii--Diard's Trogon (each 0.12%) were the rarest bird species in recently logged forest. CAP analysis indicated that avian species in thirty year post-harvested forest were more diverse and evenly distributed than recently logged forest. However, recently logged forest was rich in bird species than thirty year post- harvested forest. The results revealed that logging and retrieval process affect bird species richness and diversity. However, bird species may respond differently from habitat to habitat, i.e., forest logging causes disturbance of some avian species while recovery process may replace the loss of vegetation and harbour a wide array of avian species richness and diversity.
    Matched MeSH terms: Population Dynamics
  16. Changing roles of women: reproduction to production
    Rachapaetayakom J
    Popul Manag, 1988 Dec;2(2):18-27.
    PMID: 12282180
    Matched MeSH terms: Population Dynamics
  17. Internal migration and development transitions in South East Asia
    Pryor RJ
    Popul Geogr, 1981 Jul-Dec;3(1-2):57-68.
    PMID: 12179069
    Matched MeSH terms: Population Dynamics*
  18. Internal migrants in Peninsular Malaysia
    Pryor RJ
    J Trop Geogr, 1978;46:61-75.
    PMID: 12262749
    Matched MeSH terms: Population Dynamics*
  19. Trends in high risk births in Peninsular Malaysia in the decade following the implementation of the National Family Planning Program (1967 to 1977)
    Noor Laily Abu Bakar, Yuzuru JT, Prasanta KM
    Malays J Reprod Health, 1983 Dec;1(2):120-6.
    PMID: 12313334
    Matched MeSH terms: Population Dynamics
  20. Fulltext Conservation strategies for orangutans: reintroduction versus habitat preservation and the benefits of sustainably logged forest
    Wilson HB, Meijaard E, Venter O, Ancrenaz M, Possingham HP
    PLoS One, 2014;9(7):e102174.
    PMID: 25025134 DOI: 10.1371/journal.pone.0102174
    The Sumatran orangutan is currently listed by the IUCN as critically endangered and the Bornean species as endangered. Unless effective conservation measures are enacted quickly, most orangutan populations without adequate protection face a dire future. Two main strategies are being pursued to conserve orangutans: (i) rehabilitation and reintroduction of ex-captive or displaced individuals; and (ii) protection of their forest habitat to abate threats like deforestation and hunting. These strategies are often mirrored in similar programs to save other valued and endangered mega-fauna. Through GIS analysis, collating data from across the literature, and combining this information within a modelling and decision analysis framework, we analysed which strategy or combination of strategies is the most cost-effective at maintaining wild orangutan populations, and under what conditions. We discovered that neither strategy was optimal under all circumstances but was dependent on the relative cost per orangutan, the timescale of management concern, and the rate of deforestation. Reintroduction, which costs twelve times as much per animal as compared to protection of forest, was only a cost-effective strategy at very short timescales. For time scales longer than 10-20 years, forest protection is the more cost-efficient strategy for maintaining wild orangutan populations. Our analyses showed that a third, rarely utilised strategy is intermediate: introducing sustainable logging practices and protection from hunting in timber production forest. Maximum long-term cost-efficiency is achieved by working in conservation forest. However, habitat protection involves addressing complex conservation issues and conflicting needs at the landscape level. We find a potential resolution in that well-managed production forests could achieve intermediate conservation outcomes. This has broad implications for sustaining biodiversity more generally within an economically productive landscape. Insights from this analysis should provide a better framework to prioritize financial investments, and facilitate improved integration between the organizations that implement these strategies.
    Matched MeSH terms: Population Dynamics
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