Displaying publications 1 - 20 of 543 in total

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  1. Fulltext Circulating concentrations of vitamin D in relation to pancreatic cancer risk in European populations
    van Duijnhoven FJB, Jenab M, Hveem K, Siersema PD, Fedirko V, Duell EJ, et al.
    Int J Cancer, 2018 Mar 15;142(6):1189-1201.
    PMID: 29114875 DOI: 10.1002/ijc.31146
    Evidence from in vivo, in vitro and ecological studies are suggestive of a protective effect of vitamin D against pancreatic cancer (PC). However, this has not been confirmed by analytical epidemiological studies. We aimed to examine the association between pre-diagnostic circulating vitamin D concentrations and PC incidence in European populations. We conducted a pooled nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nord-Trøndelag Health Study's second survey (HUNT2) cohorts. In total, 738 primary incident PC cases (EPIC n = 626; HUNT2 n = 112; median follow-up = 6.9 years) were matched to 738 controls. Vitamin D [25(OH)D2 and 25(OH)D3 combined] concentrations were determined using isotope-dilution liquid chromatography-tandem mass spectrometry. Conditional logistic regression models with adjustments for body mass index and smoking habits were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (95%CI). Compared with a reference category of >50 to 75 nmol/L vitamin D, the IRRs (95% CIs) were 0.71 (0.42-1.20); 0.94 (0.72-1.22); 1.12 (0.82-1.53) and 1.26 (0.79-2.01) for clinically pre-defined categories of ≤25; >25 to 50; >75 to 100; and >100 nmol/L vitamin D, respectively (p for trend = 0.09). Corresponding analyses by quintiles of season-standardized vitamin D concentrations also did not reveal associations with PC risk (p for trend = 0.23). Although these findings among participants from the largest combination of European cohort studies to date show increasing effect estimates of PC risk with increasing pre-diagnostic concentrations of vitamin D, they are not statistically significant.
    Matched MeSH terms: Seasons
  2. Fulltext Modelling of hydrogen sulfide fate and emissions in extended aeration sewage treatment plant using TOXCHEM simulations
    Zwain HM, Nile BK, Faris AM, Vakili M, Dahlan I
    Sci Rep, 2020 12 17;10(1):22209.
    PMID: 33335267 DOI: 10.1038/s41598-020-79395-8
    Odors due to the emission of hydrogen sulfide (H2S) have been a concern in the sewage treatment plants over the last decades. H2S fate and emissions from extended aeration activated sludge (EAAS) system in Muharram Aisha-sewage treatment plant (MA-STP) were studied using TOXCHEM model. Sensitivity analysis at different aeration flowrate, H2S loading rate, wastewater pH, wastewater temperature and wind speed were studied. The predicted data were validated against actual results, where all the data were validated within the limits, and the statistical evaluation of normalized mean square error (NMSE), geometric variance (VG), and correlation coefficient (R) were close to the ideal fit. The results showed that the major processes occurring in the system were degradation and emission. During summer (27 °C) and winter (12 °C), about 25 and 23%, 1 and 2%, 2 and 2%, and 72 and 73% were fated as emitted to air, discharged with effluent, sorbed to sludge, and biodegraded, respectively. At summer and winter, the total emitted concentrations of H2S were 6.403 and 5.614 ppm, respectively. The sensitivity results indicated that aeration flowrate, H2S loading rate and wastewater pH highly influenced the emission and degradation of H2S processes compared to wastewater temperature and wind speed. To conclude, TOXCHEM model successfully predicted the H2S fate and emissions in EAAS system.
    Matched MeSH terms: Seasons
  3. Water quality influences on fish occurrences in sungai Pahang, Maran district, Pahang, Malaysia
    Zulkafli Abdul Rashid, Mohammad Noor Azmai Amal
    Sains Malaysiana, 2018;47:1941-1951.
    This study assesses the influence of water quality on fish occurrences in Sungai Pahang, Maran District, Pahang, Malaysia. Water quality and fish samplings were conducted at seven sampling sites in the district for 13 consecutive months. We used canonical correspondence analyses (CCA) to determine the influence of water quality on monthly fish species occurrences. The ranges of water quality parameters were quite high considering the measurements were made during rainy and dry seasons throughout the year. A total of 2,075 individual fish was captured which comprised of 22 different families and 65 species. Family Cyprinidae recorded the highest number of fish species of the area (27 species; 41.5%), followed by Bagridae (five species; 7.69%) and Pangasiidae (five species; 7.69%). Three fish species categorized as endangered, including Balantiocheilos melanopterus, Probarbus jullieni and Pangasianodon hypophthalmus were also collected. The collected fish species were divided into three groups (A to C), which was clearly separated in the CCA ordination diagram. The most important water quality variables for the fish occurrences in this river were pH, followed by temperature, conductivity, alkalinity and phosphate. Data analysis indicates that the occurrence of fishes were influenced by a combination of water quality parameters, but not associated with sampling month. The results present a new data from a study of fish assemblage and their habitat condition which may be important in fisheries activity and fish conservation of the river in the future.
    Matched MeSH terms: Seasons
  4. Fulltext Late-spring frost risk between 1959 and 2017 decreased in North America but increased in Europe and Asia
    Zohner CM, Mo L, Renner SS, Svenning JC, Vitasse Y, Benito BM, et al.
    Proc Natl Acad Sci U S A, 2020 06 02;117(22):12192-12200.
    PMID: 32393624 DOI: 10.1073/pnas.1920816117
    Late-spring frosts (LSFs) affect the performance of plants and animals across the world's temperate and boreal zones, but despite their ecological and economic impact on agriculture and forestry, the geographic distribution and evolutionary impact of these frost events are poorly understood. Here, we analyze LSFs between 1959 and 2017 and the resistance strategies of Northern Hemisphere woody species to infer trees' adaptations for minimizing frost damage to their leaves and to forecast forest vulnerability under the ongoing changes in frost frequencies. Trait values on leaf-out and leaf-freezing resistance come from up to 1,500 temperate and boreal woody species cultivated in common gardens. We find that areas in which LSFs are common, such as eastern North America, harbor tree species with cautious (late-leafing) leaf-out strategies. Areas in which LSFs used to be unlikely, such as broad-leaved forests and shrublands in Europe and Asia, instead harbor opportunistic tree species (quickly reacting to warming air temperatures). LSFs in the latter regions are currently increasing, and given species' innate resistance strategies, we estimate that ∼35% of the European and ∼26% of the Asian temperate forest area, but only ∼10% of the North American, will experience increasing late-frost damage in the future. Our findings reveal region-specific changes in the spring-frost risk that can inform decision-making in land management, forestry, agriculture, and insurance policy.
    Matched MeSH terms: Seasons*
  5. Horizontal heat flux between urban buildings and soil and its influencing factors
    Zhou H, Wang X, Li Y, Han F, Hu D
    Sains Malaysiana, 2016;45:689-697.
    The soil temperature near four external walls with different orientations was investigated in spring and summer. In both
    seasons, the soil temperature was higher in the positions closest to the buildings, suggesting that the buildings were a
    heat source for the soil surrounding them. Therefore, it could be confirmed that there was lateral heat transfer between
    the soil and the buildings. Based on this, a soil heat flux plate was set between the soil and the buildings to investigate the
    horizontal heat flux. The data showed diurnal variations of the horizontal heat flux in both spring and summer. In order
    to determine the factors that influenced the horizontal heat flux and to provide a basis to understand its mechanism, the
    correlations between the data of several meteorological factors and the horizontal heat flux were analysed. The results
    showed that solar radiation was significantly correlated with the horizontal heat flux (p<0.0001) in any single season and
    in the two seasons that were studied. Additionally, other meteorological factors (net radiation, air temperature, relative
    humidity and soil temperature and moisture) showed strong correlations with the horizontal heat flux on a diurnal scale
    only. On a seasonal time scale, the correlation might be significant (p<0.0001) as well, but the correlation coefficients
    decreased too significantly, such as those for soil temperature, air temperature and relative humidity. Alternatively, the
    correlation might not be significant (p>0.05), such as that for soil moisture. The stepwise regression results indicated
    that the relative importance of these meteorological factors was 48.63, 21.94, 14.44, 8.12 and 6.87% for solar radiation,
    soil temperature, air temperature, relative humidity and soil moisture, respectively, on a diurnal scale.
    Matched MeSH terms: Seasons
  6. Ecological carrying capacity assessment of diving site: A case study of Mabul Island, Malaysia
    Zhang LY, Chung SS, Qiu JW
    J Environ Manage, 2016 Dec 01;183:253-9.
    PMID: 27596939 DOI: 10.1016/j.jenvman.2016.08.075
    Despite considered a non-consumptive use of the marine environment, diving-related activities can cause damages to coral reefs. It is imminent to assess the maximum numbers of divers that can be accommodated by a diving site before it is subject to irreversible deterioration. This study aimed to assess the ecological carrying capacity of a diving site in Mabul Island, Malaysia. Photo-quadrat line transect method was used in the benthic survey. The ecological carrying capacity was assessed based on the relationship between the number of divers and the proportion of diver damaged hard corals in Mabul Island. The results indicated that the proportion of diver damaged hard corals occurred exponentially with increasing use. The ecological carrying capacity of Mabul Island is 15,600-16,800 divers per diving site per year at current levels of diver education and training with a quarterly threshold of 3900-4200 per site. Our calculation shows that management intervention (e.g. limiting diving) is justified at 8-14% of hard coral damage. In addition, the use of coral reef dominated diving sites should be managed according to their sensitivity to diver damage and the depth of the reefs.
    Matched MeSH terms: Seasons
  7. Pyrosequencing-based characterization of gastrointestinal bacteria of Atlantic salmon (Salmo salar L.) within a commercial mariculture system
    Zarkasi KZ, Abell GC, Taylor RS, Neuman C, Hatje E, Tamplin ML, et al.
    J Appl Microbiol, 2014 Jul;117(1):18-27.
    PMID: 24698479 DOI: 10.1111/jam.12514
    The relationship of Atlantic salmon gastrointestinal (GI) tract bacteria to environmental factors, in particular water temperature within a commercial mariculture system, was investigated.
    Matched MeSH terms: Seasons
  8. Trend of meiobenthos density and composition in Karah Island, South China Sea
    Zaleha K, Nasiratul_shahida MN, Siang HY, Kamaruzzaman BY
    Sains Malaysiana, 2016;45:1019-1024.
    Meiobenthos in Bidong Archipelago in coastal water of the South China Sea is hypothesised to have a certain trend of
    distribution particularly in the island ecosystem where it is usually having different type of sea bottom. Nonetheless, since
    it is located in a tropical area, the trend at the sub-tidal could be less obvious due to absent of clear season. Meiobenthic
    sampling was carried out in Karah Island, an island in Bidong Archipelago, from the intertidal, towards the sub-tidal
    zone covering the coral and non-coral area to see the trend in the density and composition. A transparent hand core
    was used to collect benthos samples. Nematoda and harpacticoid copepods dominated the intertidal and sub-tidal zone
    respectively. Harpacticoid copepods were higher in density in the non-coral sediment than the coral area. This could be
    due to the high content of silt and clay in the coral area (2.98% of silt and clay). The 2-dimension MDS analysis on the
    density data indicated the highest degree of scattering and an over-lapping condition for those intertidal and sub-tidal
    samples respectively. ANOSIM result showed that the degree of similarity was lower at the intertidal (70%) than the subtidal
    (reaching 90%) in the first sampling before both became no significant different in the second sampling. It could
    indicate the stable condition in the subtidal than the intertidal ecosystem. The comparatively low density of meiobenthos
    could indicate their response towards the environmental condition in the area which will only be confirmed by long term
    ecological study.
    Matched MeSH terms: Seasons
  9. Fulltext Training Induced Oxidative Stress-Derived DNA and Muscle Damage in Triathletes
    Zainudin H, Caszo BA, Knight VF, Gnanou JV
    Eurasian J Med, 2019 Jun;51(2):116-120.
    PMID: 31258349 DOI: 10.5152/eurasianjmed.2019.18106
    Objective: Regular moderate-intensity exercise has beneficial health effects, whereas regular strenuous exercise increases the production of oxidants that may lead to DNA, skeletal, and cardiac muscle damages. Triathletes experience strenuous muscular activity both during competition and training, being at risk of developing these tissue damages. The objective of the present study was to estimate DNA, skeletal, and cardiac muscle damages using blood biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), myoglobin, and cardiac troponin I (cTnI) among young triathletes.

    Materials and Methods: Age-matched seven male and seven female triathletes were recruited for the study. They were on a standardized training regimen and on average competed in at least one endurance event every month for the past 3-4 years. Serum biomarkers were measured using enzyme-linked immunosorbent assay at the start and at end of the racing season.

    Results: Both male and female triathletes showed a statistically significant increase in 8-OHdG. A similar pattern of increase was seen with serum myoglobin, which was not statistically significant in both male and female triathletes. cTnI levels did not show any change in both sexes.

    Conclusion: Our study shows that there could be an increased evidence of DNA damage among triathletes. However, similar effects were not observed with skeletal and cardiac muscle biomarkers.

    Matched MeSH terms: Seasons
  10. Fulltext Datasets on spatial and temporal distribution of heavy metals concentration in recent sediment at merang river system, Terengganu, Malaysia
    Zaini NM, Lee HW, Mohamed KN, Sabuti AA, Suratman S, Ong MC
    Data Brief, 2020 Aug;31:105900.
    PMID: 32642516 DOI: 10.1016/j.dib.2020.105900
    Heavy metal pollution in an aquatic environment has become of the main concern to the world due to their non-biodegradable properties, toxicity, persistence, and their ability to adsorb into food chains. With rapid industrialization and development nowadays, heavy metals are introduced continuously into the estuaries and coastal region through rivers, runoff, and land-based point sources. These heavy metals may degrade the aquatic environment and harm the living organisms and toward human indirection through secondary contact. The dataset provided is to give an overview of the spatial and temporal distribution of the heavy metals concentration in Merang River surficial sediment collected from September 2017 to July 2018, subsequently every two months dataset. Sediment samples were collected in 44 stations along the river and 20 stations in the coastal area, which total up to 64 stations. Teflon Bomb closed digestion method with mixed acid was used to digest the sediments. The concentration of heavy metals in the sediment were analysed by using Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The spatial distribution of heavy metals shows the effect of monsoon and wet and dry seasons in the sampling area. Thus, this dataset reveals six months of information on natural and anthropogenic sources intrusion at the Merang River and may also help in monitoring the pollution in the area.
    Matched MeSH terms: Seasons
  11. Fulltext Study of selective metals accumulation in green mustard (Brasissca rapa var. Parachinesis L.) from Cameron Highlands Farmlands, Pahang
    Zaini Hamzah, Marlinda Musa, Ahmad Saat
    Journal of Nuclear and Related Technologies, 2011;2011(1):1-5.
    MyJurnal
    There are many essential and non-essential elements including metals and radionuclides present in vegetables. Howeve r, the accumulation of the several metals and radionuclides might cause the contamination to vegetables itself. Green m ustard (Brasissca rapa var. Parachinesis L.) was selected to represent the vegetable in this study. Objectives of this stud y are to determine the concentration of metals and radionuclides in the samples and to calculate the enrichment factor ( EF) and also to estimate the uptake, base on biological accumulation coefficient (BAC), for the various parts of selecte d vegetables. Three farmlands in the Cameron Highlands were studied namely Bharat, Kg Raja and Bertam area. The g reen mustard and soil samples were collected during the harvest season. Samples were dried, ground and sieved prior t o analysis. Analyses for both samples were done by using X-rays Fluorescence Spectroscopy (XRF) to measure the conc entration of Fe, Zn, Hg, U and Th. The concentration of all elements in the soils is lower than their concentration in the control soil, except for Zn, U and Th. The concentration of all elements in Green Mustard is lower than their concentrat ion in the soil where it was grown. The EF values in the Brasissca rapa var. Parachinesis L are lower than 2 except for U and Th, indicating some degree of contamination due to anthropogenic activities or naturally origin. The BAC values show that Zn and Hg were accumulated in the green mustard, depending on where the plant grows.
    Matched MeSH terms: Seasons
  12. Spatial and temporal variations in Strombus canarium (Gastropoda: Strombidae) abundance at Merambong Seagrass Bed, Malaysia
    Zaidi Che Cob, Aziz Arshad, Japar Sidik Bujang, Mazlan Abd Ghaffar
    Sains Malaysiana, 2014;43:503-511.
    The abundance of marine benthic organisms often exhibits distinct distributional patterns, which is generally governed by many physical and biological factors specific to the habitat. In this study, the spatial and temporal variations in abundance of the dog conch, Strombus canarium Linnaeus 1758, a commercially important marine gastropod, was investigated. Assessment of conch abundance at Merambong seagrass bed, Malaysia, was conducted using a transect belt method. Sampling stations were randomly selected and environmental parameters associated with the habitat were recorded. The species showed distinct spatial distributional pattern. Conch densities were significantly higher in sheltered areas, mainly in mixed seagrass bed dominated by Halophila spp. and with high sediment organic content. The densities were relatively very low in areas dominated by the tape seagrass, Enhalus acoroides. The species studied also showed distinct temporal variation in abundance. The abundance value was seasonally varied with highest density recorded during the wet monsoon season (p<0.05). The densities were otherwise very low during the dry season, except for a slight peak in July. Since the conch is a very important fishery species within the Johor Straits and regulations on their harvesting is still lacking, this information would be very important for their sustainable management.
    Matched MeSH terms: Seasons
  13. Diversity and population of thrips species on legumes with special reference to megalurothrips usitatus
    Zafirah Z, Azidah A
    Sains Malaysiana, 2018;47:433-439.
    Thrips (Thysanoptera) are common pests on legume plants, yet little is known about their ecology or diversity in Peninsular
    Malaysia. In legumes, thrips are typically found in flowers, where their feeding activity causes malformations that
    eventually lead to crop damage. In this study, we examined the diversity of thrips species, particularly Megalurothrips
    usitatus, in three selected legume farms around Peninsular Malaysia (Janda Baik, Pahang; Bestari Jaya, Selangor; and
    Jelebu, Negeri Sembilan). Each month from April 2013 to May 2014, depending on growing season, legume flowers were
    inspected for thrips in five random plots from each farm. Sampling was performed six times in Bestari Jaya and Jelebu
    and twelve times in Janda Baik. The most abundant thrips species on legumes was M. usitatus (89.97%) followed by
    Thrips parvispinus (9.77%), T. hawaiiensis (0.13%) and Ceratothripoides brunneus (0.12%). The abundance of M. usitatus
    was not different between long bean, French bean and winged bean which equally distributed among different arbitrary
    strata on legume plants. Temperature and light intensity were found to be positively correlated with the abundance of
    M. usitatus, but relative humidity showed a negative relationship. M. usitatus was found in large numbers during hot
    and dry months, but in lower numbers during raining season. This study suggested that wet season may help to regulate
    the populations of M. usitatus on legume plants.
    Matched MeSH terms: Seasons
  14. The relationship between carbon dioxide flux and environmental parameters at a tropical coastal sea on different timescales
    Yusup Y, Swesi AE, Sigid MF, Almdhun HM, Jamshidi EJ
    Mar Pollut Bull, 2023 Aug;193:115106.
    PMID: 37302202 DOI: 10.1016/j.marpolbul.2023.115106
    This paper analyzes CO2 flux between the atmosphere and a tropical coastal sea using the eddy covariance technique. Coastal carbon dioxide flux studies are limited, particularly in tropical regions. Data was collected from the study site in Pulau Pinang, Malaysia, since 2015. The research found that the site is a moderate CO2 sink and experiences seasonal monsoonal changes that affect its carbon-sink or carbon-source capability. The analysis showed that the coastal sea systematically shifted from being a carbon-sink at night to a weak carbon-source during the day possibly due to cause by the synergistic influence of wind speed and seawater temperature. The CO2 flux are also influenced by small-scale, unpredictable winds, limited fetch, developing waves, and high-buoyancy conditions caused by low wind speeds and an unstable surface layer. Furthermore, it exhibited a linear relationship with wind speed. In stable conditions, the flux was influenced by wind speed and drag coefficient, while in unstable conditions, it was mostly controlled by friction velocity and atmospheric stability. These findings could improve our understanding of the critical factors that drive CO2 flux at the tropical coast.
    Matched MeSH terms: Seasons
  15. Fulltext Occurrence of Intestinal Parasitic Contamination in Select Consumed Local Raw Vegetables and Fruits in Kuantan, Pahang
    Yusof AM, Mohammad M, Abdullahi MA, Mohamed Z, Zakaria R, Wahab RA
    Trop Life Sci Res, 2017 Jan;28(1):23-32.
    PMID: 28228914 MyJurnal DOI: 10.21315/tlsr2017.28.1.2
    Intestinal parasitic infections are one of the most common causes of human diseases that result in serious health and economic issues in many developing and developed countries. Raw vegetables and fruits play an important role in transmitting parasites to humans. Hence, the aim of this study was to investigate the parasitological contamination of select commonly consumed local leafy vegetables and fruits in Kuantan, Malaysia. One kilogram of locally consumed raw vegetables and fruits were collected randomly from the Kuantan wet market (Pasar Tani) during the monsoon season (November 2014-January 2015) and the dry season (February 2015-April 2015). A standard wet mount procedure and modified Ziehl-Neelsen staining were used for the detection of parasites. In the present study, the examination of vegetables revealed five different parasite species. The vegetable samples collected from Kuantan's wet market were positive for both helminthes and protozoa. However, the fruits samples were negative for parasitic contamination. Pegaga was the most contaminated leafy vegetable in this study, and Strongyloides was the parasite found most frequently. Furthermore, there was a high diversity in the type of parasites observed during the dry season compared to the monsoon season. Therefore, further action should be taken to reduce the occurrence of parasitic contamination in vegetables by implementing the principles of good agricultural practice and improving water treatment efficacy.
    Matched MeSH terms: Seasons
  16. The effects of drainage basin geomorphometry on minimum low flow discharge: the study of small watershed in Kelang River Valley in Peninsular Malaysia
    Yunus AJ, Nakagoshi N, Salleh KO
    J Environ Sci (China), 2003 Mar;15(2):249-62.
    PMID: 12765268
    This study investigate the relationships between geomorphometric properties and the minimum low flow discharge of undisturbed drainage basins in the Taman Bukit Cahaya Seri Alam Forest Reserve, Peninsular Malaysia. The drainage basins selected were third-order basins so as to facilitate a common base for sampling and performing an unbiased statistical analyses. Three levels of relationships were observed in the study. Significant relationships existed between the geomorphometric properties as shown by the correlation network analysis; secondly, individual geomorphometric properties were observed to influence minimum flow discharge; and finally, the multiple regression model set up showed that minimum flow discharge (Q min) was dependent of basin area (AU), stream length (LS), maximum relief (Hmax), average relief (HAV) and stream frequency (SF). These findings further enforced other studies of this nature that drainage basins were dynamic and functional entities whose operations were governed by complex interrelationships occurring within the basins. Changes to any of the geomorphometric properties would influence their role as basin regulators thus influencing a change in basin response. In the case of the basin's minimum low flow, a change in any of the properties considered in the regression model influenced the "time to peak" of flow. A shorter time period would mean higher discharge, which is generally considered the prerequisite to flooding. This research also conclude that the role of geomorphometric properties to control the water supply within the stream through out the year even though during the drought and less precipitations months. Drainage basins are sensitive entities and any deteriorations involve will generate reciprocals and response to the water supply as well as the habitat within the areas.
    Matched MeSH terms: Seasons
  17. Fulltext The effects of anthropogenic disturbance and seasonality on the ant communities of Lang Tengah Island
    Yek SH, Sethu Pathy T, Yeo DYC, Gan JYS
    PeerJ, 2023;11:e16157.
    PMID: 37868047 DOI: 10.7717/peerj.16157
    Anthropogenic disturbances and seasonal changes significantly impact diversity and community composition of ants, but their effects are often intertwined. We investigated these drivers on Lang Tengah Island, a location with a pronounced monsoon season and three resorts that close during this period. We surveyed four sites, two disturbed and two undisturbed, before and after the monsoon season, using pitfall traps to sample epigaeic ant communities. Undisturbed habitats had higher species diversity, but both habitats (undisturbed and disturbed sites) have a high proportion of ants with characteristics of being encroached by generalist and invasive/tramp ant species. Post-monsoon sampling yielded an increase in species richness and diversity. Seasonal changes, such as monsoonal rains, can temporarily alter ant interactions and resource distribution, potentially maintaining diversity. Future studies should validate these findings for ant communities under similar pressures, using ant composition and functional roles for conservation and management purposes.
    Matched MeSH terms: Seasons
  18. Circadian and solar clocks interact in seasonal flowering
    Yeang HY
    Bioessays, 2009 Nov;31(11):1211-8.
    PMID: 19795408 DOI: 10.1002/bies.200900078
    The plant maintains a 24-h circadian cycle that controls the sequential activation of many physiological and developmental functions. There is empirical evidence suggesting that two types of circadian rhythms exist. Some plant rhythms appear to be set by the light transition at dawn, and are calibrated to circadian (zeitgeber) time, which is measured from sunrise. Other rhythms are set by both dawn and dusk, and are calibrated to solar time that is measured from mid-day. Rhythms on circadian timing shift seasonally in tandem with the timing of dawn that occurs earlier in summer and later in winter. On the other hand, rhythms set to solar time are maintained independently of the season, the timing of noon being constant year-round. Various rhythms that run in-phase and out-of-phase with one another seasonally may provide a means to time and induce seasonal events such as flowering.
    Matched MeSH terms: Seasons
  19. Synchronous flowering of the rubber tree (Hevea brasiliensis) induced by high solar radiation intensity
    Yeang HY
    New Phytol, 2007;175(2):283-9.
    PMID: 17587376
    How tropical trees flower synchronously near the equator in the absence of significant day length variation or other meteorological cues has long been a puzzle. The rubber tree (Hevea brasiliensis) is used as a model to investigate this phenomenon. The annual cycle of solar radiation intensity is shown to correspond closely with the flowering of the rubber tree planted near the equator and in the subtropics. Unlike in temperate regions, where incoming solar radiation (insolation) is dependent on both day length and radiation intensity, insolation at the equator is due entirely to the latter. Insolation at the upper atmosphere peaks twice a year during the spring and autumn equinoxes, but the actual solar radiation that reaches the ground is attenuated to varying extents in different localities. The rubber tree shows one or two flowering seasons a year (with major and minor seasons in the latter) in accordance with the solar radiation intensity received. High solar radiation intensity, and in particular bright sunshine (as distinct from prolonged diffuse radiation), induces synchronous anthesis and blooming in Hevea around the time of the equinoxes. The same mechanism may be operational in other tropical tree species.
    Matched MeSH terms: Seasons*
  20. An 11-Year Analysis of Emergency Presentations of Melioidosis in Northeastern Malaysia
    Yazid MB, Fauzi MH, Hasan H, Md Noh AY, Deris ZZ
    J Immigr Minor Health, 2017 Jun;19(3):774-777.
    PMID: 27160769 DOI: 10.1007/s10903-016-0429-8
    A neglected tropical disease, melioidosis is known to have variability in clinical presentations. Here, we described clinical features that should alert the physicians on the possibility of melioidosis. In this review of 86 cases from 2001 to 2011, the common presentations of melioidosis in the Emergency Department (ED), Hospital Universiti Sains Malaysia were; male gender (79.1 %), in working age group (47.8 ± 15.2 year-old), worked in contact with soil (73.3 %), presented with fever (91.9 %), in rainy season (55.8 %), have underlying diabetes mellitus (79.1 %), have leukocytosis (67.4 %) and high blood glucose (62.8 %) during presentation. In 34.9 % of cases, the antimicrobials were initiated at the ED and only 10.5 % include antimelioid drugs. Thirty-one patients (36.0 %) died due to melioidosis and 51.6 % of this were within 48 h of admission. Despite high mortality rate, the clinical awareness on the possibility of melioidosis among emergency physicians is still low and need to be strengthened.
    Matched MeSH terms: Seasons
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