Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were...Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were assessed for agro-morphological and yield traits under non-drought stress(NS)and reproductive-stage drought stress(RS)treatments.The mean comparison of traits measured between parent plants and progenies(improved lines)were similar,and there were significant and non-significant differences among the parents and improved lines(genotypes)under NS and RS.Smilarly,there was significant and non-significant differences in the interaction among both parent varieties and improved lines for NS and RS.Cluster and 3D-model of principal component analysis did not generate categorical clusters according to crossing methods,and there were no exclusive crossing method inclined variations under the treatments.The improved lines were high-yielding,disease resistant,and drought-tolerant compared with their parents.All the crossing methods were good for this crop improvement program without preference to any,despite the number of genes introgressed.展开更多
A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean ...A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters(depth: 214.73±152.22 cm, temperature 27.68±4.26℃, transparency 123±82 cm, p H 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters(p H 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life(fauna and flora) of this important fresh water body of Bangladesh.展开更多
Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value,particularly in the aquaculture sector in Malaysia.This study was conducted to determine the feeding and food items of L.c...Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value,particularly in the aquaculture sector in Malaysia.This study was conducted to determine the feeding and food items of L.canarium at dif ferent ontogenetic stages(juveniles,sub-adults and adults)from Merambong shoals,Malaysia.Field observations on feeding activity were conducted,followed by detailed laboratory analysis on the stomach content.Five-minutes observations on randomly selected individuals were conducted at the fi eld sampling site and their feeding activities were recorded with reference to age stage.Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10%formalin before being transported to the laboratory for stomach content analyses.Field observations showed that L.canarium mainly grazed on epiphytes occurring on seagrass(46.67%),followed by sediment surface(40%)and epiphytes occurring on macroalgae(13.33%).Stomach content analyses showed a signifi cant dif ference(P<0.05)in gastro-somatic index(Gasi)between the juveniles(0.39±0.05),sub-adults(0.68±0.09)and adults(0.70±0.05)(P<0.05).Food items found in the conch stomach include diatoms,detritus,foraminifera,seagrass and macroalgae fragments,sand particles and shell fragments.The Index of Relative Importance(%IRI)indicates three main types of food dominated the three ontogenetic stages namely diatoms,sand particles and detritus.However,no signifi cant diff erence(P>0.05)was detected between the three main food items(diatoms,sand particles and detritus)among the ontogenetic stages.Therefore,feeding activity revealed the role of the dog conch in the marine food network.While,classifi cation of the types of food consumed by L.canarium through stomach content analysis determines the particular position of the gastropod in the food chain.Further studies are needed to provide a better insight between trophic relationships of L.canarium with marine ecosystem.展开更多
Objective:To document movement patterns,home range,nesting behaviour and social organization of 5 individuals(3 males and 2 females) of a common species of tree-shrew,Tupaia glis(T.glis) surrounding houses of otoacari...Objective:To document movement patterns,home range,nesting behaviour and social organization of 5 individuals(3 males and 2 females) of a common species of tree-shrew,Tupaia glis(T.glis) surrounding houses of otoacariasis cases.Methods:Each shrew was fitted with a transmitter chip radio-collar which operates between the frequencies of 154.13 MHz to 154.21 MHz.Each transmitter was then tracked with a Portable Telemetry Receiver(Sirtrack,New Zealand) fitted with a 3-element Yagi antenna.Collared shrews were located using standard methods of ground-based triangulation.Each location was taken from at least 2 directional fixes and a minimum of 3 compass bearings.Fixes were taken hourly for each collared individual from the time of emergence from nest(beginning of activity) till time of entry into the nest(end of activity) every day for 5 to 7 continuous days.Three series of radio telemetry observations were carried out.The bearings,time and positions of an observer were recorded and later plotted on a graph paper in order to derive coordinates of the collared animal.[These coordinates then analyzed using Ecological Software Solutions(Biotas Version 1.03)].Results:Nests were found in a jack fruit tree,long bushes,and 2 houses.Daily telemetry detections demonstrated 2 individuals of different sex having nests(or a nest) in the same house.All shrews emerged from and returned to their nests between 0601 to 0659 hours and 1901 to 1959 hours,respectively. Both the time of exit from and entry into nest were the same between sexes(P】0.05).Their average total active period was 4.90 to 7.00 hours with a total daily travel distant of 270 m to 382 m.A male and a female shrew can move as far as 3 285 m and 4 591 m,respectively.Active movements of T.glis were during daytime.They regularly entered some houses in the area during day and night except for one individual which visited during daytime only.The sizes of home range and core area for the shrews were 2.00-3.40 ha and 0.05-0.42 ha,respectively.Generally, the mean home range size of females was 20.8%larger than that of males.Females covered a 15.4%slightly higher daily movement range compared to males.Conclusions:This is the first radio telemetry study in Malaysia to monitor movements and home range of shrews carrying ticks on their body.It demonstrates that shrews are potential carriers of ticks from wild into the houses and their compounds based on their total active periods spent moving around from fruit orchards, secondary forest,plantations and other vegetations to trees in compound of 4 to 7 houses and vice versa.There are also evidences showing shrews have close contact with humans.展开更多
The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid...The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.展开更多
In the megadiverse forests of Southeast Asia, hundreds of timber species are economically important but the population genetics of only a few taxa are known. Cross-specific amplification of microsatellite loci among c...In the megadiverse forests of Southeast Asia, hundreds of timber species are economically important but the population genetics of only a few taxa are known. Cross-specific amplification of microsatellite loci among closely related taxa could enhance our ability to study and manage previously unstudied species. We successfully utilized STMS markers in Shorea platyclados, originally developed for Shorea curtisii. The six primer pairs we tried successfully produced PCR products of expected sizes. The number of alleles observed ranged from 10 to 14 and an average of 12 alleles were detected per locus. A high expected and observed heterozygosity was observed and it ranges from 0.718 to 0.827 among all populations across all six loci tested. Microsatellite DNA markers are highly polymorphic, co-dominant, reproducible, and amenable to high throughput genetic analyses. Overall, the cross- specific amplification of microsatellite loci appears to be complicated by numerous factors. While the approach may be effective for local management and conservation ofpoorly known species, the results must be carefully interpreted.展开更多
This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in th...This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in the southern region of Peninsular Malaysia based on seven years database (2005-2011). Feed-forward ANN was used as a prediction method. The feed-forward ANN analysis demonstrated that the rotated principal component scores (RPCs) were the best input parameters to predict API. From the 4 RPCs, only 10 (CO, O3, PM10, NO2, CH4, NmHC, THC, wind direction, humidity and ambient temp) out of 12 prediction variables were the most significant parameters to predict API. The results proved that the ANN method can be applied successfully as tools for decision making and problem solving for better atmospheric management.展开更多
Study was conducted to determine the concentrations of (Ni) and (Cr) in sediment and to investigate the effect pH and organic matters on concentrations of nickel and chromium in sediment at Juru River, Penang, Malaysi...Study was conducted to determine the concentrations of (Ni) and (Cr) in sediment and to investigate the effect pH and organic matters on concentrations of nickel and chromium in sediment at Juru River, Penang, Malaysia. The sequential extraction procedure was used based on defined fractions: exchangeable, acid reduction, oxidation and residual. The concentrations of Ni and Cr in residual fraction were higher than the other fractions. In non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions (6.63 ± 3.90 μg/g-1 dry weight ) for nickel and (6.44 ± 2.10 μg/g-1 dry weight) for chromium. The pH of the sediment in all sites was acidic. The mean of total concentrations of Ni and Cr was 38.21 and 24.92 μg/g-1 dry weight, respectively. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varied throughout the river and all sites of sediments were ranged from 7.10% to 16.20%. Comparison between sampling sites using one-way analysis of variance showed that there were significant differences for Ni (P < 0.05) while there was no significant differences for Cr (P > 0.05) in changeable fraction. At acid reduction, oxidation and residual fractions, there were significant differences for the two metals (P < 0.05). For anthropogenic metals, Ni was varied significantly (P < 0.05) whereas Cr was not found significantly (P > 0.05). Analysis of pH and percentage of organic matter present in sediment conclude that Ni and Cr were not strongly correlated at oxidation fraction.展开更多
Otoliths of cultured sea bass and ambient waters were sampled from 24 fish cages and ponds in Malaysia to investigate the contents of Sr, Mg, Ba, Cd and Zn. The following elements content in otolith and water were ana...Otoliths of cultured sea bass and ambient waters were sampled from 24 fish cages and ponds in Malaysia to investigate the contents of Sr, Mg, Ba, Cd and Zn. The following elements content in otolith and water were analysed with Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and/or Atomic Absorption Spectrometer (AAS) to determine the anthropogenic impacts based on the grouping characterisation of the sampling locations. Three groups i.e. A, B and C were characterised according to the least, intermediate and high anthropogenic impact to otolith elemental content. The Enrichment Factor (EF) and Metal Pollution Index (MPI) were calculated to determine the pollution source and level. The content of Ba in otolith was found positively related with the salinity variation and Ba content in water. Elevated content of Zn in otolith and water was found in group A suggesting that oil leaking from tourist boating activities effects exceed the urbanisation and industrialisation impact. EFznsupport the enrichment of Zn in waters which exceed the recommended level. MPI showed that group A > C > B and support that tourism activities affect the pollution level and indicate otolith functioned as pollution indicator. Highest EFcdsuggested Cd incorporation onto otolith despite of the low content of Cd in water. The sequence of the elements content in otolith and water are Sr > Mg > Zn > Ba > Cd and Sr > Mg > Ba > Zn > Cd respectively.展开更多
Objective: To identify different stages of Ixodes granulatus(I. granulatus) based on morphological characters prior to molecular identification which is significant for confirming and identifying the nymphal stages of...Objective: To identify different stages of Ixodes granulatus(I. granulatus) based on morphological characters prior to molecular identification which is significant for confirming and identifying the nymphal stages of I. granulatus.Methods: A total of 14 individuals of adult, engorged and nymphal ticks collected from three different localities were examined morphologically using taxonomic keys, followed by PCR using cytochrome oxidase subunit I(COI). Clustering analysis based on COI sequences was carried out by constructing neighbor-joining and maximum parsimony tree to clarify the genetic variation and diversity of local I. granulatus.Results: Based on external morphological characterizations, nine individuals(64.3%)were successfully identified as I. granulatus, while five individuals were recognized only as Ixodes sp. due to lack of morphological characters visible and development during that stage. Molecular analysis of local I. granulatus using COI gene revealed 93%–94% sequence homology from available sequence in Gen Bank and was in concordance with the morphological identification. Furthermore, a low intraspecific variation was observed among the species of I. granulatus collected from different localities(0%–3.7%).Conclusions: These findings demonstrated for the first time the establishment of COI gene for identifying I. granulatus nymphal tick which is of paramount importance to the control of potential tick-borne infections in Malaysia. Moreover, this study provides evidence that a combination of morphology and molecular data was corroborated as an accurate tool for tick identification.展开更多
The aim of this study was to determine the source apportionment of dust fall around Lake Chini, Malaysia. Samples were collected monthly between December 2012 and March2013 at seven sampling stations located around La...The aim of this study was to determine the source apportionment of dust fall around Lake Chini, Malaysia. Samples were collected monthly between December 2012 and March2013 at seven sampling stations located around Lake Chini. The samples were filtered to separate the dissolved and undissolved solids. The ionic compositions(NO-3, SO2-4, Cl-and NH+4) were determined using ion chromatography(IC) while major elements(K, Na, Ca and Mg) and trace metals(Zn, Fe, Al, Ni, Mn, Cr, Pb and Cd) were determined using inductively coupled plasma mass spectrometry(ICP-MS). The results showed that the average concentration of total solids around Lake Chini was 93.49 ± 16.16 mg/(m2·day). SO2-4, Na and Zn dominated the dissolved portion of the dust fall. The enrichment factors(EF) revealed that the source of the trace metals and major elements in the rain water was anthropogenic, except for Fe. Hierarchical agglomerative cluster analysis(HACA) classified the seven monitoring stations and 16 variables into five groups and three groups respectively. A coupled receptor model, principal component analysis multiple linear regression(PCA-MLR), revealed that the sources of dust fall in Lake Chini were dominated by agricultural and biomass burning(42%),followed by the earth's crust(28%), sea spray(16%) and a mixture of soil dust and vehicle emissions(14%).展开更多
The Langat River in Malaysia has been experiencing anthropogenic input from urban, rural and industrial activities for many years. Sewage contamination, possibly originating from the greater than three million inhabit...The Langat River in Malaysia has been experiencing anthropogenic input from urban, rural and industrial activities for many years. Sewage contamination, possibly originating from the greater than three million inhabitants of the Langat River Basin, were examined. Sediment samples from 22 stations (SL01-SL22) along the Langat River were collected, extracted and analysed by GC-MS. Six different sterols were identified and quantified. The highest sterol concentration was found at station SL02 (618.29 ng/g dry weight), which situated in the Balak River whereas the other sediment samples ranged between 11.60 and 446.52 ng/g dry weight. Sterol ratios were used to identify sources, occurrence and partitioning of faecal matter in sediments and majority of the ratios clearly demonstrated that sewage contamination was occurring at most stations in the Langat River. A multivariate statistical analysis was used in conjunction with a combination of biomarkers to better understand the data that clearly separated the compounds. Most sediments of the Langat River were found to contain low to mid-range sewage contamination with some containing 'significant' levels of contamination. This is the first report on sewage pollution in the Langat River based on a combination of biomarker and multivariate statistical approaches that will establish a new standard for sewage detection using faecal sterols.展开更多
Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix, collected from Johor coastal waters, Malaysia, were studied. ...Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix, collected from Johor coastal waters, Malaysia, were studied. Growth pattern by length-weight relationship (W=aLb) for the sexes differed, and exhibited positive allometric growth (male, female and combined sexes of T. chatareus; female and combined sexes of T. jaculatrix) and isometric growth (male samples of T. jaculatrix only). Trophic levels of both species were analyzed based on 128 specimens. The results show that, in both species, crustaceans and insects were the most abundant prey items, and among crustaceans the red clawed crab Sesarma bidens and Formicidae family insects were the most represented taxa. The estimated mean trophic levels for T. chatareus and T. jaculatrix were 3.422±0.009 and 3.420±0.020, respectively, indicating that they are largely carnivores. Fecundity of T. chatareus ranged from 38 354 to 147 185 eggs for females with total length ranging from 14.5 to 22.5 cm and total body weight from 48.7 to 270.2 g, and T. jaculatrix 25 251 to 150 456 eggs for females with total length ranging from 12.2 to 23.0 cm and total body weight from 25.7 to 275.0 g. Differences in values of gonadosomatic and hepatosomatic indexes calculated for both species in this study may have resulted from uneven sample size ranges.展开更多
Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia...Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia, particularly from Sumatra, Indonesia, particulate matter PM2.5 is found to be one of the dangerous sources of airborne pollution and is known to seriously affect human health. This study determines the composition of carbohydrates (as levoglucosan), surfactants, major elements, and anions in PM2.5 during a 2013 haze episode. PM2.5 samples were collected from Universiti Kebangsaan Malaysia, Bangi, using a high volume sampler during a seven-day monitoring campaign during the peak of that year's haze episode. PM2.5 concentrations ranged between 14.52 and 160.93 μg/m3, exceeding the 2005 WHO air quality guidelines for PM2.5 (25 μg/m3 for 24-h mean). The patterns for levoglucosan, surfactants, major elements, and anionic compositions were proportional to the PM2.5 concentrations. Changes in PM2.5 observed on days 3 and 4 were influenced by a combination of meteorological factors, which substantiate the theory that such factors play a pivotal role in haze episodes.展开更多
S: A dichotomous key and descriptions of the species of pitcher plants recorded from bris forest at Jambu Bongkok is given. Three species of pitcher plants were recognized from the study area. They are Nepenthes raffl...S: A dichotomous key and descriptions of the species of pitcher plants recorded from bris forest at Jambu Bongkok is given. Three species of pitcher plants were recognized from the study area. They are Nepenthes rafflesiana, Nepenthes gracilis and Nepenthes mirabilis. These species can easily be identified by their morphological differences. Nepenthes gracilis differed from the other two species in having triangular stem, sessile leaves, winged leaf base, under lid surface of the pitcher sparsely covered with honey glands, inner pitcher cavity wall covered exposed digestive glands and very narrow peristome with the thickness of ≤ 1 cm. On the other hand, Nepenthes rafflesiana and Nepenthes mirabilis have cylindrical stem, stalked leaves, semi-amplexicaul leaf base, under lid surface densely covered with honey glands, inner pitcher cavity wall covered with overarched digestive glands and broad peristome with a thickness of ≥1 cm. Nepenthes rafflesiana can be differentiated from Nepenthes mirabilis by its infundibulate upper pitcher, ellipsoidal lower pitcher, inner pitcher wall cavity wholly covered with digestive glands whereas Nepenthes mirabilis have tublose-ventricose upper and lower pitchers, inner pitcher cavity wall of both pitchers partly covered with digestive glands.展开更多
This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametr...This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.展开更多
The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh b...The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty.Total 600 fish samples were derived from commercial catches from July 2018 to June 2019.Periodic differences in sex ratio,size distribution,condition factor(Kn),fecundity,gonadosomatic index and gonadal maturation cycle were assessed.The results showed 384(64%)female and 216(36%)male with an overall sex ratio of 1.77:1(female:male).Mean total length(TL)and body weight(BW)of all fish studied were 14.85±3.38 cm TL and 27.54±15.76 g,respectively.The Kn varied with length groups,the highest(1.45±0.23)and lowest(0.89±0.18)values obtained in 16.0-16.9 and 10.0-10.9 cm TL groups,respectively.The highest Kn was documented in October while the lowest was in January.Monthly GSI values showed two peaks in July and November for both the sexes.The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968±3047 with 14.4-18.3 cm in TL and 19.97-34.7g in BW.The relationship of fecundity with TL and BW was F=1.385TL13.405,r^(2)=0.885 and F=5.201BW^(4.827),r^(2)=0.944.Partial behavior of spawning together with allochronic oocytes development has also been found through histology.The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change.展开更多
基金supported by the Higher Institution Centre of Excellence(HiCoE)Research Grant(Grant No.6369105)。
文摘Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were assessed for agro-morphological and yield traits under non-drought stress(NS)and reproductive-stage drought stress(RS)treatments.The mean comparison of traits measured between parent plants and progenies(improved lines)were similar,and there were significant and non-significant differences among the parents and improved lines(genotypes)under NS and RS.Smilarly,there was significant and non-significant differences in the interaction among both parent varieties and improved lines for NS and RS.Cluster and 3D-model of principal component analysis did not generate categorical clusters according to crossing methods,and there were no exclusive crossing method inclined variations under the treatments.The improved lines were high-yielding,disease resistant,and drought-tolerant compared with their parents.All the crossing methods were good for this crop improvement program without preference to any,despite the number of genes introgressed.
基金Supported by the United States Department of Agriculture(USDA) through the Project ‘‘Ex situ conservation of some indigenous fishes of Bangladesh by selecting the best stock through DNA markers’’(BGARS-120)
文摘A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel——a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters(depth: 214.73±152.22 cm, temperature 27.68±4.26℃, transparency 123±82 cm, p H 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters(p H 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life(fauna and flora) of this important fresh water body of Bangladesh.
基金Supported by the Ministry of Science,Technology and Innovation,Malaysia (MOSTI) through UKM Fundamental Research Grant(No.FRGS/2/2014/STWN10/UKM/02/1)the Centre for Research and Innovation Management Grant(CRIM)(No.AP-2012-013)
文摘Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value,particularly in the aquaculture sector in Malaysia.This study was conducted to determine the feeding and food items of L.canarium at dif ferent ontogenetic stages(juveniles,sub-adults and adults)from Merambong shoals,Malaysia.Field observations on feeding activity were conducted,followed by detailed laboratory analysis on the stomach content.Five-minutes observations on randomly selected individuals were conducted at the fi eld sampling site and their feeding activities were recorded with reference to age stage.Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10%formalin before being transported to the laboratory for stomach content analyses.Field observations showed that L.canarium mainly grazed on epiphytes occurring on seagrass(46.67%),followed by sediment surface(40%)and epiphytes occurring on macroalgae(13.33%).Stomach content analyses showed a signifi cant dif ference(P<0.05)in gastro-somatic index(Gasi)between the juveniles(0.39±0.05),sub-adults(0.68±0.09)and adults(0.70±0.05)(P<0.05).Food items found in the conch stomach include diatoms,detritus,foraminifera,seagrass and macroalgae fragments,sand particles and shell fragments.The Index of Relative Importance(%IRI)indicates three main types of food dominated the three ontogenetic stages namely diatoms,sand particles and detritus.However,no signifi cant diff erence(P>0.05)was detected between the three main food items(diatoms,sand particles and detritus)among the ontogenetic stages.Therefore,feeding activity revealed the role of the dog conch in the marine food network.While,classifi cation of the types of food consumed by L.canarium through stomach content analysis determines the particular position of the gastropod in the food chain.Further studies are needed to provide a better insight between trophic relationships of L.canarium with marine ecosystem.
文摘Objective:To document movement patterns,home range,nesting behaviour and social organization of 5 individuals(3 males and 2 females) of a common species of tree-shrew,Tupaia glis(T.glis) surrounding houses of otoacariasis cases.Methods:Each shrew was fitted with a transmitter chip radio-collar which operates between the frequencies of 154.13 MHz to 154.21 MHz.Each transmitter was then tracked with a Portable Telemetry Receiver(Sirtrack,New Zealand) fitted with a 3-element Yagi antenna.Collared shrews were located using standard methods of ground-based triangulation.Each location was taken from at least 2 directional fixes and a minimum of 3 compass bearings.Fixes were taken hourly for each collared individual from the time of emergence from nest(beginning of activity) till time of entry into the nest(end of activity) every day for 5 to 7 continuous days.Three series of radio telemetry observations were carried out.The bearings,time and positions of an observer were recorded and later plotted on a graph paper in order to derive coordinates of the collared animal.[These coordinates then analyzed using Ecological Software Solutions(Biotas Version 1.03)].Results:Nests were found in a jack fruit tree,long bushes,and 2 houses.Daily telemetry detections demonstrated 2 individuals of different sex having nests(or a nest) in the same house.All shrews emerged from and returned to their nests between 0601 to 0659 hours and 1901 to 1959 hours,respectively. Both the time of exit from and entry into nest were the same between sexes(P】0.05).Their average total active period was 4.90 to 7.00 hours with a total daily travel distant of 270 m to 382 m.A male and a female shrew can move as far as 3 285 m and 4 591 m,respectively.Active movements of T.glis were during daytime.They regularly entered some houses in the area during day and night except for one individual which visited during daytime only.The sizes of home range and core area for the shrews were 2.00-3.40 ha and 0.05-0.42 ha,respectively.Generally, the mean home range size of females was 20.8%larger than that of males.Females covered a 15.4%slightly higher daily movement range compared to males.Conclusions:This is the first radio telemetry study in Malaysia to monitor movements and home range of shrews carrying ticks on their body.It demonstrates that shrews are potential carriers of ticks from wild into the houses and their compounds based on their total active periods spent moving around from fruit orchards, secondary forest,plantations and other vegetations to trees in compound of 4 to 7 houses and vice versa.There are also evidences showing shrews have close contact with humans.
基金funded by e-Science 02-01-02-SF0403 from the Ministry of Science,Technology and Innovation,Malaysia
文摘The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.
基金financially supported by Texas Tech University in the form of start-up and faculty research enhancement grants
文摘In the megadiverse forests of Southeast Asia, hundreds of timber species are economically important but the population genetics of only a few taxa are known. Cross-specific amplification of microsatellite loci among closely related taxa could enhance our ability to study and manage previously unstudied species. We successfully utilized STMS markers in Shorea platyclados, originally developed for Shorea curtisii. The six primer pairs we tried successfully produced PCR products of expected sizes. The number of alleles observed ranged from 10 to 14 and an average of 12 alleles were detected per locus. A high expected and observed heterozygosity was observed and it ranges from 0.718 to 0.827 among all populations across all six loci tested. Microsatellite DNA markers are highly polymorphic, co-dominant, reproducible, and amenable to high throughput genetic analyses. Overall, the cross- specific amplification of microsatellite loci appears to be complicated by numerous factors. While the approach may be effective for local management and conservation ofpoorly known species, the results must be carefully interpreted.
文摘This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in the southern region of Peninsular Malaysia based on seven years database (2005-2011). Feed-forward ANN was used as a prediction method. The feed-forward ANN analysis demonstrated that the rotated principal component scores (RPCs) were the best input parameters to predict API. From the 4 RPCs, only 10 (CO, O3, PM10, NO2, CH4, NmHC, THC, wind direction, humidity and ambient temp) out of 12 prediction variables were the most significant parameters to predict API. The results proved that the ANN method can be applied successfully as tools for decision making and problem solving for better atmospheric management.
文摘Study was conducted to determine the concentrations of (Ni) and (Cr) in sediment and to investigate the effect pH and organic matters on concentrations of nickel and chromium in sediment at Juru River, Penang, Malaysia. The sequential extraction procedure was used based on defined fractions: exchangeable, acid reduction, oxidation and residual. The concentrations of Ni and Cr in residual fraction were higher than the other fractions. In non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions (6.63 ± 3.90 μg/g-1 dry weight ) for nickel and (6.44 ± 2.10 μg/g-1 dry weight) for chromium. The pH of the sediment in all sites was acidic. The mean of total concentrations of Ni and Cr was 38.21 and 24.92 μg/g-1 dry weight, respectively. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varied throughout the river and all sites of sediments were ranged from 7.10% to 16.20%. Comparison between sampling sites using one-way analysis of variance showed that there were significant differences for Ni (P < 0.05) while there was no significant differences for Cr (P > 0.05) in changeable fraction. At acid reduction, oxidation and residual fractions, there were significant differences for the two metals (P < 0.05). For anthropogenic metals, Ni was varied significantly (P < 0.05) whereas Cr was not found significantly (P > 0.05). Analysis of pH and percentage of organic matter present in sediment conclude that Ni and Cr were not strongly correlated at oxidation fraction.
文摘Otoliths of cultured sea bass and ambient waters were sampled from 24 fish cages and ponds in Malaysia to investigate the contents of Sr, Mg, Ba, Cd and Zn. The following elements content in otolith and water were analysed with Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and/or Atomic Absorption Spectrometer (AAS) to determine the anthropogenic impacts based on the grouping characterisation of the sampling locations. Three groups i.e. A, B and C were characterised according to the least, intermediate and high anthropogenic impact to otolith elemental content. The Enrichment Factor (EF) and Metal Pollution Index (MPI) were calculated to determine the pollution source and level. The content of Ba in otolith was found positively related with the salinity variation and Ba content in water. Elevated content of Zn in otolith and water was found in group A suggesting that oil leaking from tourist boating activities effects exceed the urbanisation and industrialisation impact. EFznsupport the enrichment of Zn in waters which exceed the recommended level. MPI showed that group A > C > B and support that tourism activities affect the pollution level and indicate otolith functioned as pollution indicator. Highest EFcdsuggested Cd incorporation onto otolith despite of the low content of Cd in water. The sequence of the elements content in otolith and water are Sr > Mg > Zn > Ba > Cd and Sr > Mg > Ba > Zn > Cd respectively.
基金Supported by National Institute of Health grant from the Ministry of Health,Malaysia(Code:JPP-IMR 11-010)
文摘Objective: To identify different stages of Ixodes granulatus(I. granulatus) based on morphological characters prior to molecular identification which is significant for confirming and identifying the nymphal stages of I. granulatus.Methods: A total of 14 individuals of adult, engorged and nymphal ticks collected from three different localities were examined morphologically using taxonomic keys, followed by PCR using cytochrome oxidase subunit I(COI). Clustering analysis based on COI sequences was carried out by constructing neighbor-joining and maximum parsimony tree to clarify the genetic variation and diversity of local I. granulatus.Results: Based on external morphological characterizations, nine individuals(64.3%)were successfully identified as I. granulatus, while five individuals were recognized only as Ixodes sp. due to lack of morphological characters visible and development during that stage. Molecular analysis of local I. granulatus using COI gene revealed 93%–94% sequence homology from available sequence in Gen Bank and was in concordance with the morphological identification. Furthermore, a low intraspecific variation was observed among the species of I. granulatus collected from different localities(0%–3.7%).Conclusions: These findings demonstrated for the first time the establishment of COI gene for identifying I. granulatus nymphal tick which is of paramount importance to the control of potential tick-borne infections in Malaysia. Moreover, this study provides evidence that a combination of morphology and molecular data was corroborated as an accurate tool for tick identification.
基金the Malaysian Ministry of Higher Education for funding via Fundamental Research Grants (UKMTOPDOWN-ST-08-FRGS0003-2010 and FRGS/1/ 2013/SPWN01/UKM/02/)
文摘The aim of this study was to determine the source apportionment of dust fall around Lake Chini, Malaysia. Samples were collected monthly between December 2012 and March2013 at seven sampling stations located around Lake Chini. The samples were filtered to separate the dissolved and undissolved solids. The ionic compositions(NO-3, SO2-4, Cl-and NH+4) were determined using ion chromatography(IC) while major elements(K, Na, Ca and Mg) and trace metals(Zn, Fe, Al, Ni, Mn, Cr, Pb and Cd) were determined using inductively coupled plasma mass spectrometry(ICP-MS). The results showed that the average concentration of total solids around Lake Chini was 93.49 ± 16.16 mg/(m2·day). SO2-4, Na and Zn dominated the dissolved portion of the dust fall. The enrichment factors(EF) revealed that the source of the trace metals and major elements in the rain water was anthropogenic, except for Fe. Hierarchical agglomerative cluster analysis(HACA) classified the seven monitoring stations and 16 variables into five groups and three groups respectively. A coupled receptor model, principal component analysis multiple linear regression(PCA-MLR), revealed that the sources of dust fall in Lake Chini were dominated by agricultural and biomass burning(42%),followed by the earth's crust(28%), sea spray(16%) and a mixture of soil dust and vehicle emissions(14%).
基金the Universiti Kebangsaan Malaysia for the OUP Fund(OUP-UKM-FST-2011)
文摘The Langat River in Malaysia has been experiencing anthropogenic input from urban, rural and industrial activities for many years. Sewage contamination, possibly originating from the greater than three million inhabitants of the Langat River Basin, were examined. Sediment samples from 22 stations (SL01-SL22) along the Langat River were collected, extracted and analysed by GC-MS. Six different sterols were identified and quantified. The highest sterol concentration was found at station SL02 (618.29 ng/g dry weight), which situated in the Balak River whereas the other sediment samples ranged between 11.60 and 446.52 ng/g dry weight. Sterol ratios were used to identify sources, occurrence and partitioning of faecal matter in sediments and majority of the ratios clearly demonstrated that sewage contamination was occurring at most stations in the Langat River. A multivariate statistical analysis was used in conjunction with a combination of biomarkers to better understand the data that clearly separated the compounds. Most sediments of the Langat River were found to contain low to mid-range sewage contamination with some containing 'significant' levels of contamination. This is the first report on sewage pollution in the Langat River based on a combination of biomarker and multivariate statistical approaches that will establish a new standard for sewage detection using faecal sterols.
基金Project supported by the Malaysia government through UKM- Science Fund (No. 04-01-02-SF0124)the fellowship of Skim Universiti Kebangsaan Malaysia (No. UKM-OUP-FST-2008)
文摘Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix, collected from Johor coastal waters, Malaysia, were studied. Growth pattern by length-weight relationship (W=aLb) for the sexes differed, and exhibited positive allometric growth (male, female and combined sexes of T. chatareus; female and combined sexes of T. jaculatrix) and isometric growth (male samples of T. jaculatrix only). Trophic levels of both species were analyzed based on 128 specimens. The results show that, in both species, crustaceans and insects were the most abundant prey items, and among crustaceans the red clawed crab Sesarma bidens and Formicidae family insects were the most represented taxa. The estimated mean trophic levels for T. chatareus and T. jaculatrix were 3.422±0.009 and 3.420±0.020, respectively, indicating that they are largely carnivores. Fecundity of T. chatareus ranged from 38 354 to 147 185 eggs for females with total length ranging from 14.5 to 22.5 cm and total body weight from 48.7 to 270.2 g, and T. jaculatrix 25 251 to 150 456 eggs for females with total length ranging from 12.2 to 23.0 cm and total body weight from 25.7 to 275.0 g. Differences in values of gonadosomatic and hepatosomatic indexes calculated for both species in this study may have resulted from uneven sample size ranges.
文摘Haze episodes have become a major concern in Malaysia over the past few decades and have an increasingly important impact on the country each and every year. During haze episodes from biomass burning in Southeast Asia, particularly from Sumatra, Indonesia, particulate matter PM2.5 is found to be one of the dangerous sources of airborne pollution and is known to seriously affect human health. This study determines the composition of carbohydrates (as levoglucosan), surfactants, major elements, and anions in PM2.5 during a 2013 haze episode. PM2.5 samples were collected from Universiti Kebangsaan Malaysia, Bangi, using a high volume sampler during a seven-day monitoring campaign during the peak of that year's haze episode. PM2.5 concentrations ranged between 14.52 and 160.93 μg/m3, exceeding the 2005 WHO air quality guidelines for PM2.5 (25 μg/m3 for 24-h mean). The patterns for levoglucosan, surfactants, major elements, and anionic compositions were proportional to the PM2.5 concentrations. Changes in PM2.5 observed on days 3 and 4 were influenced by a combination of meteorological factors, which substantiate the theory that such factors play a pivotal role in haze episodes.
文摘S: A dichotomous key and descriptions of the species of pitcher plants recorded from bris forest at Jambu Bongkok is given. Three species of pitcher plants were recognized from the study area. They are Nepenthes rafflesiana, Nepenthes gracilis and Nepenthes mirabilis. These species can easily be identified by their morphological differences. Nepenthes gracilis differed from the other two species in having triangular stem, sessile leaves, winged leaf base, under lid surface of the pitcher sparsely covered with honey glands, inner pitcher cavity wall covered exposed digestive glands and very narrow peristome with the thickness of ≤ 1 cm. On the other hand, Nepenthes rafflesiana and Nepenthes mirabilis have cylindrical stem, stalked leaves, semi-amplexicaul leaf base, under lid surface densely covered with honey glands, inner pitcher cavity wall covered with overarched digestive glands and broad peristome with a thickness of ≥1 cm. Nepenthes rafflesiana can be differentiated from Nepenthes mirabilis by its infundibulate upper pitcher, ellipsoidal lower pitcher, inner pitcher wall cavity wholly covered with digestive glands whereas Nepenthes mirabilis have tublose-ventricose upper and lower pitchers, inner pitcher cavity wall of both pitchers partly covered with digestive glands.
基金supported by Newton-Ungku Omar Grant (XX-2017-002)
文摘This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.
基金supported by Sylhet Agricultural University Research System(SAURES)Bangladesh through the research grant#SAU/Director(Research)-80/18/351(15).
文摘The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty.Total 600 fish samples were derived from commercial catches from July 2018 to June 2019.Periodic differences in sex ratio,size distribution,condition factor(Kn),fecundity,gonadosomatic index and gonadal maturation cycle were assessed.The results showed 384(64%)female and 216(36%)male with an overall sex ratio of 1.77:1(female:male).Mean total length(TL)and body weight(BW)of all fish studied were 14.85±3.38 cm TL and 27.54±15.76 g,respectively.The Kn varied with length groups,the highest(1.45±0.23)and lowest(0.89±0.18)values obtained in 16.0-16.9 and 10.0-10.9 cm TL groups,respectively.The highest Kn was documented in October while the lowest was in January.Monthly GSI values showed two peaks in July and November for both the sexes.The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968±3047 with 14.4-18.3 cm in TL and 19.97-34.7g in BW.The relationship of fecundity with TL and BW was F=1.385TL13.405,r^(2)=0.885 and F=5.201BW^(4.827),r^(2)=0.944.Partial behavior of spawning together with allochronic oocytes development has also been found through histology.The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change.