Large charnockite massifs occur in the high-grade Southern Granulite Terrain (SGT) and Eastern Ghats Belt (EGB) crustal provinces of Peninsular India. Available geochronological data indicate that the magmatism is...Large charnockite massifs occur in the high-grade Southern Granulite Terrain (SGT) and Eastern Ghats Belt (EGB) crustal provinces of Peninsular India. Available geochronological data indicate that the magmatism is episodic, associated with distinct orogenic cycles in the different crustal domains. The geochemical data also indicate a change in composition from trondhjemitic at - 3.0-2.9 Ga to domi- nantly tonalitic at - 2.6-2.5 Ga to tonalitic-granodiorite-granitic at - 2.0--1.9 Ga to dominantly tonalitic at 1.7--1.6 Ga to quartz monzonitic or tonalitic at - 1.0-0.9 Ga to granodiorite-granitic at - 0.8-0.7 Ga. The trondhjemitic and tonalitic end members are metaluminous, magnesian and calcic to calc-alkalic, characteristic of magnesian group charnockites. The granodioritic to granitic end members are metalumi- nous to slightly peraluminous, ferroan and calc-alkalic to alkali-calcic, characteristic of ferroan group charnockites. The quartz monzonitic end members are metaluminous to peraluminous, magnesian to ferro- an and calcic to calc-alkalic, neither characteristic of the magnesian group nor of the ferroan group of char- nockites. Based on the occurrence and difference in composition of the charnockite massifs, it is suggested that the charnockite magmatism registers the crustal growth of the Indian plate on its southern (SGT) and eastern (EGB) sides, along active continental margins by accretion of arcs.展开更多
At the moment, there is no system to evaluate climate suitability for rubber cultivation. Most of land evaluation systems in Peninsular Malaysia often overlooked climate as not important on the assumption that the eff...At the moment, there is no system to evaluate climate suitability for rubber cultivation. Most of land evaluation systems in Peninsular Malaysia often overlooked climate as not important on the assumption that the effect of climatic factors on rubber yield are small. The system to evaluate climate suitability follows the FAO (Food and Agriculture Organization) Framework for Laud Evaluation but employs a parametric approach using climatic data which are easily available. The climatic criteria used are mean annual temperature, mean daily maximum temperature, mean daily minimum temperature, mean annual rainfall, length of dry season, amount of sunshine, maximum wind speed and mean annual relative humidity. The evaluation of climate was carried out using information from nine meteorological stations in Peninsular Malaysia viz. Alor Star (Kedah), Ipoh (Perak), Subang (Selangor), Malacca (Malacca), Kluang (Johore), Senai (Johore), Kuantan (Pahang), Kuala Krai (Kelantan) and Tanah Merah (Kelantan). The results for actual suitability classification showed that eight of the stations are highly suitable (S1) for rubber cultivation with land indices ranging from 75 to 93. One station Alor Star is moderately suitable (S2y) due to dry season. The results for potential suitability classification showed that all the stations are highly suitable for rubber cultivation with land indices ranging from 90 to 99.展开更多
The effects of tidal currents(i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutiv...The effects of tidal currents(i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons(May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia(ECPM),south of the South China Sea(SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal(O_1 and K_1) and semidiurnal(M_2) tidal currents. The spectral density of residual currents(detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency(K_1) and small peaks at the semidiurnal tidal frequency(M_2)indicating the existence of internal tides. The result of the horizontal kinetic energy(HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux(16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July.展开更多
Upwelling off the east coast of Peninsular Malaysia (PM) was detected from recent cruise data collected during the southwest monsoon. Thermocline lifting was observed at 104?E from a number of parallel transects. To c...Upwelling off the east coast of Peninsular Malaysia (PM) was detected from recent cruise data collected during the southwest monsoon. Thermocline lifting was observed at 104?E from a number of parallel transects. To confirm the presence of upwelling, satellite remote sensing data were used, and numerical model experiments were conducted. A cooler sea-surface temperature along the coast was spotted from both in-situ and satellite data while upward movement from the model agreed with field data. The southwesterly wind that blows along PM from June to September is believed to be the important mechanism that contributed to this upwelling through an Ekman dynamics process.展开更多
For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circ...For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes (higher high flows, and lower low flows) at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.展开更多
Twenty four soils of Peninsular Malaysia derived from a varied geology and providing a range of particle size classes as well as different profile development stages were chosen for the study. Land characteristics and...Twenty four soils of Peninsular Malaysia derived from a varied geology and providing a range of particle size classes as well as different profile development stages were chosen for the study. Land characteristics and land qualities were used to determine the land suitability for oil palm cultivation. The results show that land characteristics have stronger influence on the yield of oil palm compared to land qualities. The use of the Framework for Land Evaluation together with the combined limitation-parametric approach enabled a more meaningful interpretation of the land units. Results demonstrated that land characteristics are recommended for land evaluation for oil palm cultivation.展开更多
We illustrate intricate genetic relationship between prolonged extensional tectonics,formation of several sedimentary basins,enormous Cretaceous volcanism and emplacement of great dyke swarms as well assequential
Surface sediments and giant mudskipper (Periophthalmodon schlosseri) were collected in August and September 2008 and in March and June 2010 from six sampling sites in the west coast of Peninsular Malaysia to assess he...Surface sediments and giant mudskipper (Periophthalmodon schlosseri) were collected in August and September 2008 and in March and June 2010 from six sampling sites in the west coast of Peninsular Malaysia to assess heavy metals accumulation in the giant mudskipper. Sequential extraction technique was used to fractionate the sediments into four different geo-chemical fractions;easily, freely or leachable and exchangeable (EFLE), acid reducible, oxidizable organic and resistant fractions. Heavy metals concentrations (Cu, Zn, Pb, Cd and Ni) in the surface sediments and giant mudskipper were determined by using air acetylene flame atomic absorption spectrophotometer (AAS) Perkin Elmer Analyst 800. The results of Pearson’s correlation analyses showed that metal concentrations in the tissues of P. schlosseri were significantly correlated (p p < 0.05), correlations were observed between Cu in P. schlosseri and Cu in the sediment (oxidisable-organic, resistant and total Cu), Zn in P. schlosseri and Zn in the sediment (EFLE and total Zn), Pb in P. schlosseri and Pb in the sediment (with all the four fractions of Pb), Cd and Ni in P. schlosseri and Cd and Ni in the sediment (with all fractions of Cd and Ni except acid-reducible Cd and Ni) which might suggest the use of P. schlosseri as a biomonitoring agent for heavy metals pollution in the west coast of Peninsular Malaysia.展开更多
The present work assesses the trace metal content in groundwater from Akwa-Mundemba, Bakassi Peninsular in Cameroon. 12 groundwater samples were analyzed using Inductively Coupled Plasma Mass Spectroscopy ICP-MS. Fiel...The present work assesses the trace metal content in groundwater from Akwa-Mundemba, Bakassi Peninsular in Cameroon. 12 groundwater samples were analyzed using Inductively Coupled Plasma Mass Spectroscopy ICP-MS. Field measurement of physicochemical parameters was determined. R-mode statistical analysis;Pearson’s Correlation Analysis (PCA) together with Hierarchical Cluster Analysis (HCA) between the trace metals and the physico-chemical parameters was carried out. Ten indices were determined: Four trace metal hazard indices;the average daily dose ADD (2.5E—07 to 0.2)) carcinogenic risks CR (2.1E—06 to 9.9E—04) and the non-carcinogenic risk hazard quotient HQ (5.7E—04 to 0.78) which yields the hazard indices HI (0.1 - 0.78), and six trace metal pollution indices;Degree of contamination DC (—13.53 to —11.02), Enrichment factor EF (0.26 - 35.47), Ecological risk factor Er (—29.92 - 7.04), Potential ecological risk index RI (-61.2-43.43), Pollution load index PLI (—0.01 - 0.04) and Geo-accumulation index Igeo (4.8E-09-3.0). From health risk indices and pollution evaluation indices on trace metals, the groundwater in Akwa-Mundemba area is safe for drinking. The enrichment factors show that the sources of the trace metals are from geogenic and anthropogenic processes. Arsenic, Lead and Vanadium are enriched although they are below the hazard risk values;this shows they have pollution potential that could be attributed to weathering and agricultural wastes. The severity of metal toxicity is governed by several factors, such as dose, nutrition, age, and even life style. Therefore, these low trends might not guarantee the complete absence of human health risks. Generally, from risk assessment on trace metals using risk indices in the analyzed groundwater samples might not cause any health risk. However, due to an increasing level of environmental pollution that might be imposed by increasing human activity in this area, groundwater sources might become a potential sink of contaminants;this is significant reason that makes constant monitoring, implementation and treatment of groundwater for drinking purposes necessary.展开更多
Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human a...Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human activities mainly from residents and transportation. A study was conducted to determine the distribution and sources of heavy metals (Cd, Cu and Zn) in the sediments of Kelana Jaya Lakes. Concentrations of Cd, Cu, and Zn for surface sediment were determined by using aqua-regia method and sequential extraction technique. Total Cd concentrations ranged from 0.48 μg/g to 2.68 μg/g dry weight (dw) for all lakes. Total Cd concentrations in sediment of all lakes exceeded CCME (Canadian Council of Ministers of the Environment, 2001) guidelines. Total Cu concentrations ranged from 7.37 μg/g to 73.6 μg/g (dw). Only Cu concentration in one lake exceeded the CCME guidelines besides having the highest mean concentration among all. Total Zn concentrations ranged from 107 μg/g to 529 μg/g (dw). Again, The Zn concentrations in three lakes were found to exceed CCME guidelines for Zn concentration in freshwater sediment. Geochemical study on sediment revealed that nonresistant fractions for Cd, Cu and Zn for other lakes there were higher than ‘resistant’ fraction. The elevated levels and most percentages (>50%) of nonresistant fractions of Cu and Zn indicated that lakes in the park, especially near oxidation pond and monsoon drains, could have received anthropogenic metals from domestic wastes. Rehabilitation program and regular biomonitoring at Kelana Jaya Lakes are therefore recommended.展开更多
Three different aquatic ecosystems(an urban pond,Kelana Jaya Pond;a polluted river,Sepang River;and the intertidal and offshore areas of the west coast of Peninsular Malaysia)with different sets of ecological backgrou...Three different aquatic ecosystems(an urban pond,Kelana Jaya Pond;a polluted river,Sepang River;and the intertidal and offshore areas of the west coast of Peninsular Malaysia)with different sets of ecological backgrounds and human activities were reviewed and assessed for the levels of Cu and Zn contamination with special reference to those found in polluted sediments collected from the Sepang River.The discussion on the contamination levels of Cu and Zn in the aquatic environment of Peninsular Malaysia was based on a comparison of the metal contamination of 4 kinds of aquatic environments.The comparison of 4 different areas was based on ① total concentrations of 2 metals;② the concentrations and percentages of the nonresistant(EFLE,acid-reducible and oxidisable-organic)and resistant geochemical fractions;and ③ correlation coefficients(R-values)based on data of 4 areas separately and a combination of 4 areas.The Sepang River recorded nonresistant fractions of 63.1% for Zn and 55.8% for Cu in addition to slightly lower metal concentrations when compared to those(60%-70%)reported before the shutting down of the piggery activities in that area.These nonresistant metal percentages(55%-63%)indicated that the metal concentrations were still dominated by anthropogenic sources since nonresistant fraction of metals were mostly contributed by anthropogenic sources.The positive results from the four different aquatic environments assessed here provided strong evidence to show that Malaysia's aquatic environment had received anthropogenic Cu and Zn.The present study also showed that the percentage of the nonresistant fraction and the R-values based on correlation analysis of Cu and Zn could be used as indicators of Cu and Zn pollution in the Malaysian aquatic ecosystem.Based on the present data,the correlation coefficients(R-values)are potential indicators of EFLE Cu and acid-reducible Cu of the sediments.The use of R-values as indicators of metal pollution is suggested and it is applicable to other heavy metal data although it should be improved in future studies.展开更多
A study on Zn and Cu concentrations in 2 species of intertidal crabs,namely Uca annulipes and Dotilla myctiroides collected from the intertidal coastal area of Selangor(5 sites) and Negeri Sembilan(3 sites),west coast...A study on Zn and Cu concentrations in 2 species of intertidal crabs,namely Uca annulipes and Dotilla myctiroides collected from the intertidal coastal area of Selangor(5 sites) and Negeri Sembilan(3 sites),west coast of Peninsular Malaysia,was carried out.The various localized sources of Zn and Cu discharges towards both the crab species were mentioned.A comparative study between the 2 crab species also revealed that the concentrations of Zn and Cu were significantly(P<0.05) higher in U.annulipes when compared to D.myctiroides.This difference was related to the organic matter percentage in the crabs' microhabitat sediments since metals can be associated with the organic matter of sediments in which they might ingest.Significantly(P<0.05) higher organic matter content was shown in U.annulipes sediments when compared to D.myctiroides sediments for all stations.The metal and size relationship in the crabs was also investigated.The relationships between Zn and Cu concentrations with body weight and carapace width of U.annulipes and D.myctiroides were significantly(P<0.01 and P<0.05) correlated although the pair wise was weak.展开更多
On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, ...On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, we provide an overview of this earthquake, focusing on the slip distribution of the mainshock and its relationship with the preceding swarm. We also reexamined the source areas of other large earthquakes that occurred around the Sea of Japan in the past and compared them with the Matsushiro earthquake swarm in central Japan from1964 to 1968. The difference between the Matsushiro earthquake swarm and the Noto earthquake swarm is the surrounding stress field. The Matsushiro earthquake swarm was a strike-slip stress field, so the cracks in the crust were oriented vertically. This allowed fluids seeped from the depths to rise and flow out to the surface. On the other hand, the Noto area was a reverse fault stress field. Therefore, the cracks in the earth's crust were oriented horizontally. Fluids flowing underground in deep areas could not rise and spread over a wide area in the horizontal plane. This may have caused a large amount of fluid to accumulate underground, triggering a large earthquake. Although our proposed mechanism does not take into account other complex geological conditions into consideration, it may provide a simple way to explain why the Noto swarm is followed by a large earthquake while other swarms are not.展开更多
This study aims to predict monthly columnar ozone in Peninsular Malaysia based on concentrations of several atmospheric gases. Data pertaining to five atmo- spheric gases (CO2, 03, CH4, NO2, and H2O vapor) were retr...This study aims to predict monthly columnar ozone in Peninsular Malaysia based on concentrations of several atmospheric gases. Data pertaining to five atmo- spheric gases (CO2, 03, CH4, NO2, and H2O vapor) were retrieved by satellite scanning imaging absorption spectro- metry for atmospheric chartography from 2003 to 2008 and used to develop a model to predict columnar ozone in Peninsular Malaysia. Analyses of the northeast monsoon (NEM) and the southwest monsoon (SWM) seasons were conducted separately. Based on the Pearson correlation matrices, columnar ozone was negatively correlated with HzO vapor but positively correlated with COz and NO2 during both the NEM and SWM seasons from 2003 to 2008. This result was expected because NO/is a precursor of ozone. Therefore, an increase in columnar ozone concentration is associated with an increase in NO2 but a decrease in H/O vapor. In the NEM season, columnar ozone was negatively correlated with H20 (-0.847), NO2 (0.754), and CO2 (0.477); columnar ozone was also negatively but weakly correlated with CH4 (-0.035). In the SWM season, columnar ozone was highly positively correlated with NO2 (0.855), CO2 (0.572), and CH4(0.321) and also highly negatively correlated with H2O(-0.832). Both multiple regression and principal component analyses were used to predict the columnar ozone value in Peninsular Malaysia. We obtained the best-fitting regression equations for the columnar ozone data using four independent variables. Our results show approxi- mately the same R value (≈0.83) for both the NEM and SWM seasons.展开更多
Background:Intestinal parasitic infections(IPIs)among indigenous people have been widely documented in Malaysia,however,the prevalence of these infections remains high.In the past,most studies have focused on specific...Background:Intestinal parasitic infections(IPIs)among indigenous people have been widely documented in Malaysia,however,the prevalence of these infections remains high.In the past,most studies have focused on specific species of parasites but polyparasitism has received limited attention.In addition,epidemiology studies on indigenous people tend to consider them as a homogenous group,whereas in reality different sub-ethnic groups have different cultural and living practices.Variations in living habits such as personal hygiene practices may predispose different groups to different parasitic infections.To better understand prevalence and risk factors of intestinal parasitism among different sub-ethnic groups,the present study was conducted among two sub-ethnic groups of indigenous people(Temuan and Mah Meri)residing in Selangor state,Malaysia.Methods:A cross-sectional study that focused on two distinct sub-ethnic groups was carried out from February to September 2014.Faecal samples were collected from 186 participants and examined using the formalin-ether sedimentation technique.A molecular approach was adopted to conduct a genetic characterisation of the parasites.Additionally,questionnaires were administered to obtain information on the demographics,socioeconomic backgrounds and behavioural risks relating to the participants,as well as information about their environments.Statistical analyses(i.e.binary and multivariate logistic regression analyses)were performed to measure risk factors.Results:For Temuan communities,trichuriasis(64.2%)was the most common infection found,preceding hookworm infection(34%),ascariasis(7.5%),giardiasis(14.2%)and amoebiasis(7.5%).As for the Mah Meri communities,trichuriasis(77.5%)prevailed over ascariasis(21.3%),hookworm(15%),giardiasis(7.5%)and amoebiasis(3.8%).Significant differences in proportions of trichuriasis,ascariasis and hookworm infections were observed between the Temuan and Mah Meri sub-ethnic groups.Polyparasitism was more common among the Temuan sub-ethnic group(41.5%)compared to the Mah Meri sub-ethnic group(32.5%),with the majority of participants harbouring two parasites concurrently(Temuan:33%,Mah Meri:20%).Trichuris trichiura and Ascaris lumbricoides co-infections were most prevalent(10%)among the Mah Meri communities,while a co-infection of T.trichiura with hookworm(19.8%)was most common among the Temuan communities.Multivariate analyses showed that being unemployed,having a large family and drinking unboiled water were found to be significantly associated with intestinal parasitism.Conclusion:The present study highlights substantial polyparasitism and risk factors for infections in the Temuan and Mah Meri sub-ethnic groups.The high prevalence of IPIs among these two sub-ethnic groups indicates that parasitic infections are important health issues in these communities.Hence,it is imperative to implement sound intervention strategies such as periodic preventive chemotherapy coupled with health education in order to reduce and eradicate these infections.展开更多
文摘Large charnockite massifs occur in the high-grade Southern Granulite Terrain (SGT) and Eastern Ghats Belt (EGB) crustal provinces of Peninsular India. Available geochronological data indicate that the magmatism is episodic, associated with distinct orogenic cycles in the different crustal domains. The geochemical data also indicate a change in composition from trondhjemitic at - 3.0-2.9 Ga to domi- nantly tonalitic at - 2.6-2.5 Ga to tonalitic-granodiorite-granitic at - 2.0--1.9 Ga to dominantly tonalitic at 1.7--1.6 Ga to quartz monzonitic or tonalitic at - 1.0-0.9 Ga to granodiorite-granitic at - 0.8-0.7 Ga. The trondhjemitic and tonalitic end members are metaluminous, magnesian and calcic to calc-alkalic, characteristic of magnesian group charnockites. The granodioritic to granitic end members are metalumi- nous to slightly peraluminous, ferroan and calc-alkalic to alkali-calcic, characteristic of ferroan group charnockites. The quartz monzonitic end members are metaluminous to peraluminous, magnesian to ferro- an and calcic to calc-alkalic, neither characteristic of the magnesian group nor of the ferroan group of char- nockites. Based on the occurrence and difference in composition of the charnockite massifs, it is suggested that the charnockite magmatism registers the crustal growth of the Indian plate on its southern (SGT) and eastern (EGB) sides, along active continental margins by accretion of arcs.
文摘At the moment, there is no system to evaluate climate suitability for rubber cultivation. Most of land evaluation systems in Peninsular Malaysia often overlooked climate as not important on the assumption that the effect of climatic factors on rubber yield are small. The system to evaluate climate suitability follows the FAO (Food and Agriculture Organization) Framework for Laud Evaluation but employs a parametric approach using climatic data which are easily available. The climatic criteria used are mean annual temperature, mean daily maximum temperature, mean daily minimum temperature, mean annual rainfall, length of dry season, amount of sunshine, maximum wind speed and mean annual relative humidity. The evaluation of climate was carried out using information from nine meteorological stations in Peninsular Malaysia viz. Alor Star (Kedah), Ipoh (Perak), Subang (Selangor), Malacca (Malacca), Kluang (Johore), Senai (Johore), Kuantan (Pahang), Kuala Krai (Kelantan) and Tanah Merah (Kelantan). The results for actual suitability classification showed that eight of the stations are highly suitable (S1) for rubber cultivation with land indices ranging from 75 to 93. One station Alor Star is moderately suitable (S2y) due to dry season. The results for potential suitability classification showed that all the stations are highly suitable for rubber cultivation with land indices ranging from 90 to 99.
基金The Higher Institutional Centre of Excellent Universiti Malaysia Terengganu under contract No.TJ66928the Malaysia Coastal Observation Network Project under the Institute of Oceanography and Environment,Universiti Malaysia Terengganu of Malaysia
文摘The effects of tidal currents(i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons(May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia(ECPM),south of the South China Sea(SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal(O_1 and K_1) and semidiurnal(M_2) tidal currents. The spectral density of residual currents(detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency(K_1) and small peaks at the semidiurnal tidal frequency(M_2)indicating the existence of internal tides. The result of the horizontal kinetic energy(HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux(16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July.
文摘Upwelling off the east coast of Peninsular Malaysia (PM) was detected from recent cruise data collected during the southwest monsoon. Thermocline lifting was observed at 104?E from a number of parallel transects. To confirm the presence of upwelling, satellite remote sensing data were used, and numerical model experiments were conducted. A cooler sea-surface temperature along the coast was spotted from both in-situ and satellite data while upward movement from the model agreed with field data. The southwesterly wind that blows along PM from June to September is believed to be the important mechanism that contributed to this upwelling through an Ekman dynamics process.
文摘For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes (higher high flows, and lower low flows) at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.
文摘Twenty four soils of Peninsular Malaysia derived from a varied geology and providing a range of particle size classes as well as different profile development stages were chosen for the study. Land characteristics and land qualities were used to determine the land suitability for oil palm cultivation. The results show that land characteristics have stronger influence on the yield of oil palm compared to land qualities. The use of the Framework for Land Evaluation together with the combined limitation-parametric approach enabled a more meaningful interpretation of the land units. Results demonstrated that land characteristics are recommended for land evaluation for oil palm cultivation.
文摘We illustrate intricate genetic relationship between prolonged extensional tectonics,formation of several sedimentary basins,enormous Cretaceous volcanism and emplacement of great dyke swarms as well assequential
文摘Surface sediments and giant mudskipper (Periophthalmodon schlosseri) were collected in August and September 2008 and in March and June 2010 from six sampling sites in the west coast of Peninsular Malaysia to assess heavy metals accumulation in the giant mudskipper. Sequential extraction technique was used to fractionate the sediments into four different geo-chemical fractions;easily, freely or leachable and exchangeable (EFLE), acid reducible, oxidizable organic and resistant fractions. Heavy metals concentrations (Cu, Zn, Pb, Cd and Ni) in the surface sediments and giant mudskipper were determined by using air acetylene flame atomic absorption spectrophotometer (AAS) Perkin Elmer Analyst 800. The results of Pearson’s correlation analyses showed that metal concentrations in the tissues of P. schlosseri were significantly correlated (p p < 0.05), correlations were observed between Cu in P. schlosseri and Cu in the sediment (oxidisable-organic, resistant and total Cu), Zn in P. schlosseri and Zn in the sediment (EFLE and total Zn), Pb in P. schlosseri and Pb in the sediment (with all the four fractions of Pb), Cd and Ni in P. schlosseri and Cd and Ni in the sediment (with all fractions of Cd and Ni except acid-reducible Cd and Ni) which might suggest the use of P. schlosseri as a biomonitoring agent for heavy metals pollution in the west coast of Peninsular Malaysia.
文摘The present work assesses the trace metal content in groundwater from Akwa-Mundemba, Bakassi Peninsular in Cameroon. 12 groundwater samples were analyzed using Inductively Coupled Plasma Mass Spectroscopy ICP-MS. Field measurement of physicochemical parameters was determined. R-mode statistical analysis;Pearson’s Correlation Analysis (PCA) together with Hierarchical Cluster Analysis (HCA) between the trace metals and the physico-chemical parameters was carried out. Ten indices were determined: Four trace metal hazard indices;the average daily dose ADD (2.5E—07 to 0.2)) carcinogenic risks CR (2.1E—06 to 9.9E—04) and the non-carcinogenic risk hazard quotient HQ (5.7E—04 to 0.78) which yields the hazard indices HI (0.1 - 0.78), and six trace metal pollution indices;Degree of contamination DC (—13.53 to —11.02), Enrichment factor EF (0.26 - 35.47), Ecological risk factor Er (—29.92 - 7.04), Potential ecological risk index RI (-61.2-43.43), Pollution load index PLI (—0.01 - 0.04) and Geo-accumulation index Igeo (4.8E-09-3.0). From health risk indices and pollution evaluation indices on trace metals, the groundwater in Akwa-Mundemba area is safe for drinking. The enrichment factors show that the sources of the trace metals are from geogenic and anthropogenic processes. Arsenic, Lead and Vanadium are enriched although they are below the hazard risk values;this shows they have pollution potential that could be attributed to weathering and agricultural wastes. The severity of metal toxicity is governed by several factors, such as dose, nutrition, age, and even life style. Therefore, these low trends might not guarantee the complete absence of human health risks. Generally, from risk assessment on trace metals using risk indices in the analyzed groundwater samples might not cause any health risk. However, due to an increasing level of environmental pollution that might be imposed by increasing human activity in this area, groundwater sources might become a potential sink of contaminants;this is significant reason that makes constant monitoring, implementation and treatment of groundwater for drinking purposes necessary.
文摘Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human activities mainly from residents and transportation. A study was conducted to determine the distribution and sources of heavy metals (Cd, Cu and Zn) in the sediments of Kelana Jaya Lakes. Concentrations of Cd, Cu, and Zn for surface sediment were determined by using aqua-regia method and sequential extraction technique. Total Cd concentrations ranged from 0.48 μg/g to 2.68 μg/g dry weight (dw) for all lakes. Total Cd concentrations in sediment of all lakes exceeded CCME (Canadian Council of Ministers of the Environment, 2001) guidelines. Total Cu concentrations ranged from 7.37 μg/g to 73.6 μg/g (dw). Only Cu concentration in one lake exceeded the CCME guidelines besides having the highest mean concentration among all. Total Zn concentrations ranged from 107 μg/g to 529 μg/g (dw). Again, The Zn concentrations in three lakes were found to exceed CCME guidelines for Zn concentration in freshwater sediment. Geochemical study on sediment revealed that nonresistant fractions for Cd, Cu and Zn for other lakes there were higher than ‘resistant’ fraction. The elevated levels and most percentages (>50%) of nonresistant fractions of Cu and Zn indicated that lakes in the park, especially near oxidation pond and monsoon drains, could have received anthropogenic metals from domestic wastes. Rehabilitation program and regular biomonitoring at Kelana Jaya Lakes are therefore recommended.
文摘Three different aquatic ecosystems(an urban pond,Kelana Jaya Pond;a polluted river,Sepang River;and the intertidal and offshore areas of the west coast of Peninsular Malaysia)with different sets of ecological backgrounds and human activities were reviewed and assessed for the levels of Cu and Zn contamination with special reference to those found in polluted sediments collected from the Sepang River.The discussion on the contamination levels of Cu and Zn in the aquatic environment of Peninsular Malaysia was based on a comparison of the metal contamination of 4 kinds of aquatic environments.The comparison of 4 different areas was based on ① total concentrations of 2 metals;② the concentrations and percentages of the nonresistant(EFLE,acid-reducible and oxidisable-organic)and resistant geochemical fractions;and ③ correlation coefficients(R-values)based on data of 4 areas separately and a combination of 4 areas.The Sepang River recorded nonresistant fractions of 63.1% for Zn and 55.8% for Cu in addition to slightly lower metal concentrations when compared to those(60%-70%)reported before the shutting down of the piggery activities in that area.These nonresistant metal percentages(55%-63%)indicated that the metal concentrations were still dominated by anthropogenic sources since nonresistant fraction of metals were mostly contributed by anthropogenic sources.The positive results from the four different aquatic environments assessed here provided strong evidence to show that Malaysia's aquatic environment had received anthropogenic Cu and Zn.The present study also showed that the percentage of the nonresistant fraction and the R-values based on correlation analysis of Cu and Zn could be used as indicators of Cu and Zn pollution in the Malaysian aquatic ecosystem.Based on the present data,the correlation coefficients(R-values)are potential indicators of EFLE Cu and acid-reducible Cu of the sediments.The use of R-values as indicators of metal pollution is suggested and it is applicable to other heavy metal data although it should be improved in future studies.
文摘A study on Zn and Cu concentrations in 2 species of intertidal crabs,namely Uca annulipes and Dotilla myctiroides collected from the intertidal coastal area of Selangor(5 sites) and Negeri Sembilan(3 sites),west coast of Peninsular Malaysia,was carried out.The various localized sources of Zn and Cu discharges towards both the crab species were mentioned.A comparative study between the 2 crab species also revealed that the concentrations of Zn and Cu were significantly(P<0.05) higher in U.annulipes when compared to D.myctiroides.This difference was related to the organic matter percentage in the crabs' microhabitat sediments since metals can be associated with the organic matter of sediments in which they might ingest.Significantly(P<0.05) higher organic matter content was shown in U.annulipes sediments when compared to D.myctiroides sediments for all stations.The metal and size relationship in the crabs was also investigated.The relationships between Zn and Cu concentrations with body weight and carapace width of U.annulipes and D.myctiroides were significantly(P<0.01 and P<0.05) correlated although the pair wise was weak.
基金supported by the National Nature Science Foundation of China (No. 42130312)。
文摘On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, we provide an overview of this earthquake, focusing on the slip distribution of the mainshock and its relationship with the preceding swarm. We also reexamined the source areas of other large earthquakes that occurred around the Sea of Japan in the past and compared them with the Matsushiro earthquake swarm in central Japan from1964 to 1968. The difference between the Matsushiro earthquake swarm and the Noto earthquake swarm is the surrounding stress field. The Matsushiro earthquake swarm was a strike-slip stress field, so the cracks in the crust were oriented vertically. This allowed fluids seeped from the depths to rise and flow out to the surface. On the other hand, the Noto area was a reverse fault stress field. Therefore, the cracks in the earth's crust were oriented horizontally. Fluids flowing underground in deep areas could not rise and spread over a wide area in the horizontal plane. This may have caused a large amount of fluid to accumulate underground, triggering a large earthquake. Although our proposed mechanism does not take into account other complex geological conditions into consideration, it may provide a simple way to explain why the Noto swarm is followed by a large earthquake while other swarms are not.
文摘This study aims to predict monthly columnar ozone in Peninsular Malaysia based on concentrations of several atmospheric gases. Data pertaining to five atmo- spheric gases (CO2, 03, CH4, NO2, and H2O vapor) were retrieved by satellite scanning imaging absorption spectro- metry for atmospheric chartography from 2003 to 2008 and used to develop a model to predict columnar ozone in Peninsular Malaysia. Analyses of the northeast monsoon (NEM) and the southwest monsoon (SWM) seasons were conducted separately. Based on the Pearson correlation matrices, columnar ozone was negatively correlated with HzO vapor but positively correlated with COz and NO2 during both the NEM and SWM seasons from 2003 to 2008. This result was expected because NO/is a precursor of ozone. Therefore, an increase in columnar ozone concentration is associated with an increase in NO2 but a decrease in H/O vapor. In the NEM season, columnar ozone was negatively correlated with H20 (-0.847), NO2 (0.754), and CO2 (0.477); columnar ozone was also negatively but weakly correlated with CH4 (-0.035). In the SWM season, columnar ozone was highly positively correlated with NO2 (0.855), CO2 (0.572), and CH4(0.321) and also highly negatively correlated with H2O(-0.832). Both multiple regression and principal component analyses were used to predict the columnar ozone value in Peninsular Malaysia. We obtained the best-fitting regression equations for the columnar ozone data using four independent variables. Our results show approxi- mately the same R value (≈0.83) for both the NEM and SWM seasons.
基金supported by the University of Malaya Research Grant(RG494-13HTM)the University of Malaya Postgraduate Research Grant(PG032-2014B).
文摘Background:Intestinal parasitic infections(IPIs)among indigenous people have been widely documented in Malaysia,however,the prevalence of these infections remains high.In the past,most studies have focused on specific species of parasites but polyparasitism has received limited attention.In addition,epidemiology studies on indigenous people tend to consider them as a homogenous group,whereas in reality different sub-ethnic groups have different cultural and living practices.Variations in living habits such as personal hygiene practices may predispose different groups to different parasitic infections.To better understand prevalence and risk factors of intestinal parasitism among different sub-ethnic groups,the present study was conducted among two sub-ethnic groups of indigenous people(Temuan and Mah Meri)residing in Selangor state,Malaysia.Methods:A cross-sectional study that focused on two distinct sub-ethnic groups was carried out from February to September 2014.Faecal samples were collected from 186 participants and examined using the formalin-ether sedimentation technique.A molecular approach was adopted to conduct a genetic characterisation of the parasites.Additionally,questionnaires were administered to obtain information on the demographics,socioeconomic backgrounds and behavioural risks relating to the participants,as well as information about their environments.Statistical analyses(i.e.binary and multivariate logistic regression analyses)were performed to measure risk factors.Results:For Temuan communities,trichuriasis(64.2%)was the most common infection found,preceding hookworm infection(34%),ascariasis(7.5%),giardiasis(14.2%)and amoebiasis(7.5%).As for the Mah Meri communities,trichuriasis(77.5%)prevailed over ascariasis(21.3%),hookworm(15%),giardiasis(7.5%)and amoebiasis(3.8%).Significant differences in proportions of trichuriasis,ascariasis and hookworm infections were observed between the Temuan and Mah Meri sub-ethnic groups.Polyparasitism was more common among the Temuan sub-ethnic group(41.5%)compared to the Mah Meri sub-ethnic group(32.5%),with the majority of participants harbouring two parasites concurrently(Temuan:33%,Mah Meri:20%).Trichuris trichiura and Ascaris lumbricoides co-infections were most prevalent(10%)among the Mah Meri communities,while a co-infection of T.trichiura with hookworm(19.8%)was most common among the Temuan communities.Multivariate analyses showed that being unemployed,having a large family and drinking unboiled water were found to be significantly associated with intestinal parasitism.Conclusion:The present study highlights substantial polyparasitism and risk factors for infections in the Temuan and Mah Meri sub-ethnic groups.The high prevalence of IPIs among these two sub-ethnic groups indicates that parasitic infections are important health issues in these communities.Hence,it is imperative to implement sound intervention strategies such as periodic preventive chemotherapy coupled with health education in order to reduce and eradicate these infections.