Deep structure of the Southeast Asian curved subduction system and its dynamic process

The deep structure,material circulation,and dynamic processes in the Southeast Asia have long been an elusive scientific puzzle due to the lack of systematic scientific observations and recognized theoretical models.Based on the deep seismic tomography using long-period natural earthquake data,in this study,the deep structure and material circulation of the curved subduction system in Southeast Asia was studied,and the dynamic processes since 100 million years ago was reconstructed.It is pointed out that challenges still exist in the precise reconstruction of deep mantle structures of the study area,the influence of multi-stage subduction on deep material exchange and shallow magma activity,as well as the spatiotemporal evolution and coupling mechanism of multi-plate convergence.Future work should focus on high-resolution land-sea joint 3-D seismic tomography imaging of the curved subduction system in the Southeast Asia,combined with geochemical analysis and geodynamic modelling works.

Evaluation of Rice Germplasm from Southeast Asia

Totaling 662 rice germplasms were collected from Southeast Asia,including 120 wild species and 542 cultivated rice plants.An information database of the collections was constructed after phenotype identification.Based on evaluation of cultivated rice,some germplasm resources were found to have good characteristics,including 58 accessions resistant to brown planthopper,nine accessions resistant to rice blast,eleven accessions resistant to bacterial blight,and twelve accessions with salt-tolerance.The introduced rice resources broaden genetic basis of rice and enrich rice genbank in China,which would play an active role in rice genetic research and rice breeding.

Impact of El Nino on Large-scale Circulation of Southeast Asian Summer Monsoon

Multi-year SST and NCEP/NCAR reanalyzed wind data were employed to study the impacts of El Nio on the Southeast Asian summer monsoon (SEASM). It was found that the impacts of El Nio on the SEASM differed distinctly from those on the East Asian summer monsoon (EASM) and the Indian summer monsoon (ISM). Composite analysis indicated that the "gear point" of coupling between the Indo-monsoon circulation and the Pacific-Walker circulation was located in the western margins of Southeast Asia when the developing stage of El Nio events covered the boreal summer. The anomalous circulations in the lower and upper troposphere and divergent circulation are all favorable for the strengthening of the SEASM during this period. Following the evolution of El Nio, the "gear point" of the two cells shifted eastward to the central Pacific when the mature or decaying period of El Nio events covered the boreal summer. The anomalous circulations are favorable for the weakening of the SEASM. The anomalous indexes of intensity of SEASM accord well with the above results. Additionally, the difference of SSTA patterns in the tropical Indo-Pacific Ocean between the two stages of the El Nio may play an important role.

Re-delineating mountainous areas with three topographic parameters in Mainland Southeast Asia using ASTER global digital elevation model data

Tropical mountainous areas not only provide substantial carbon storage and play an important role in global biological diversity, but also provide basic livelihood for a large number of poor ethnic minorities. However, there is no unified and explicit definition for mountainous areas. The local elevation range(LER) is a crucial structural parameter for delineating mountainous areas. However, current LER products are limited by the subjective selection of an optimum statistical window or coarser spatial resolution of topographical data. In this study, we presented an approach using thresholds for three topographic parameters, elevation, slope, and LER, derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM) to redelineate the vast mountainous areas of mainland Southeast Asia(MSEA). The mean change-point analysis method was applied to determine the optimum statistical window of the 1 arc second(approximately 30 m)-resolution GDEM LER. The results showed that: First, the optimum statistical window is 38 × 38 cell units(width × height) in a rectangular neighborhood, or an area of about 1.30 km^2 for calculating GDEM LER in MSEA. Second, the LER of more than 80% of the area ranges from 30 m to 499 m in MSEA. The LERs in the northern and northwestern MSEA are greater than their counterparts in the south and east. Third, the area of the re-delineated mountainous areas was 83.52 × 10~4 km^2, about 38.71% of the total area. Spatially, the mountainous areas are mainly distributed in the north and northeast of MSEA. The re-delineated 30-m resolution map of the mountainous areas will serve as a topographical dataset for monitoring mountainrelated land surface changes in MSEA. The parameter-modified mountain extraction procedure can be expanded to delineate global mountainous areas.

Effect of climate change on seasonal monsoon in Asia and its impact on the variability of monsoon rainfall in Southeast Asia

Global warming and climate change is one of the most extensively researched and discussed topical issues affecting the environment.Although there are enough historical evidence to support the theory that climate change is a natural phenomenon,many research scientists are widely in agreement that the increase in temperature in the 20 th century is anthropologically related.The associated effects are the variability of rainfall and cyclonic patterns that are being observed globally.In Southeast Asia the link between global warming and the seasonal atmospheric flow during the monsoon seasons shows varying degree of fuzziness.This study investigates the impact of climate change on the seasonality of monsoon Asia and its effect on the variability of monsoon rainfall in Southeast Asia.The comparison of decadal variation of precipitation and temperature anomalies before the 1970 s found general increases which were mostly varying.But beyond the 1970 s,global precipitation anomalous showed increases that almost corresponded with increases in global temperature anomalies for the same period.There are frequent changes and a shift westward of the Indian summer monsoon.Although precipitation is observed to be 70%below normal levels,in some areas the topography affects the intensity of rainfall.These shifting phenomenon of other monsoon season in the region are impacting on the variability of rainfall and the onset of monsoons in Southeast Asia and is predicted to delay for 15 days the onset of the monsoon in the future.The variability of monsoon rainfall in the SEA region is observed to be decadal and the frequency and intensity of intermittent flooding of some areas during the monsoon season have serious consequences on the human,financial,infrastructure and food security of the region.

Taxonomy is the cornerstone of biodiversity conservation SEABRI reports on biological surveys in Southeast Asia

The Southeast Asia Biodiversity Research Institute （SEABRI） is an international scientific research and education organization affiliated directly to the Chinese Academy of Sciences （CAS） and managed by the Xishuangbanna Tropical Botanical Garden （XTBG）. By harnessing its connections with all CAS institutes, local institutes and international agencies and leveraging on their resources, it seeks to make a significant contribution to biodiversity conservation in Southeast Asia.

The characteristics, formation and exploration progress of the potash deposits on the Khorat Plateau, Thailand and Laos, Southeast Asia

The giant potash deposit on the Khorat Plateau is one of the most promising targets for exploitation of potassium salts.So far,many researches and geologic survey have been conducted on the giant potash deposits.Hence,it is necessary to make an overall review on the potash deposits.The potash deposit on the Khorat Plateau was formed during the Middle to Late Cretaceous,during which seawater was enriched in Ca2+and depleted in SO42-compared with those of modern seawater.In addition to seawater,continental water and hydrothermal fluids could have affected the evaporite basins.The seawater was probably derived from Tethys ocean,and the brine should have evaporated to some extent before entering into the basin systems based on the evidence of absence of carbonates and unproportionate sulphate compared with chloride salts.The paleo-climate during Middle to Late Cretaceous was characterized as high temperature and extremely arid environment,which is favourable for deposition of potassium-magnesium saline minerals.The major saline minerals are of anhydrite,halite,carnallite,sylvite and,tachyhydrite,with trace amounts of borates.The resources of the potash deposit on the Khorat Plateau could be approximately as much as 400×109 t of carnallite and 7×109 t of sylvite.The evaporite sequences have been deformed and altered by postdepositinal processes,including tectonic movements and chemical alteration.Salt domes were formed in the postdepositional processes.Based on the analyses of geophysical surveys and drilling projects,high-quality sylvinite ores are commonly found at the flanks of those salt domes due to incongruent dissolution of carnallite.The furure potential prospecting areas for the highquality sylvinite ores would be on the edges of the Khorat Plateau.

Phylogenetic Patterns of the Southeast Asian Tree Frog Chiromantis hansenae in Thailand

Although landscape features such as mountains and rivers are recognized often as limiting factors to amphibian dispersal and gene flow, a limited number of studies have investigated such patterns across Southeast Asia. A perfect example of this is Thailand, located in one of the world＇s biodiversity hotspot regions. Thailand represents the corridor between mainland Asia and the Sunda Shelf, a famous and widely recognized biogeographic region, and yet there are few studies on the genetic structure among populations of amphibian species distributed across Thailand. The Southeast Asian tree frog, Chiromantis hansenae has been reported to possess a geographic range that is restricted to Thailand and, presumably, Cambodia~ Here, we investigate phylogenetic relationships among C. hansenae populations using partial sequences of the mitochondrial 16S rRNA gene and nuclear POMC gene. Our results reveal two distinct evolutionary lineages within C. hansenae populations in Thailand. The genetic divergence among populations between these two clades is considerable, and results support inter-population divergence, and high genetic differentiation （pairwise FsT = 0.97）, between two localities sampled in western Thailand （TK1 and TK2）, separated from each other by 40 kilometers only. The results suggest that landscape features across Thailand may have a profound impact on patterns of diversification in the country, underscoring the urgent need for fine-scale investigations of genetic structure of endemic and ＂widespread＂ species.

Application of remote sensing technique to mapping of the map series of karst geology in China and Southeast Asia

Based on the mapping program of the map series of karst geology in China and Southeast Asia, the paper summarizes the application of remote sensing technique and the process of acquiring information from remote sensing images. Generally, remote sensing technique serves as an effective method to recognize information about karst topography, rocky desertification and karst collapse. Interpretation of remote sensing images, in combination with field verification and cartographic generalization, provides basic data for updating the program database and compiling synthetic maps. In interpreting remote sensing images, automatic extraction can make it more efficient and visual interpretation can improve its accuracy.

Assessing the sensitivity of RegCM4 to cumulus and ocean surface schemes over the Southeast Asia domain of the coordinated regional climate downscaling experiment

Multi-year experiments are conducted using the most recent version of the Abdus Salam International Centre for Theoretical Physics regional climate model RegCM4(version 4.7) to customize its performance over Southeast Asia - a region with few RCMs applied to date. The model is driven by ERA-Interim reanalysis data at a grid spacing of 25 km using the CORDEX(Coordinated Regional Climate Downscaling Experiment) Southeast Asia domain. The authors focus on comparing the convection schemes of Emanuel and Tiedtke(Tiedtke-1) and Tiedtke with effects of sea surface evaporation introduced(Tiedtke-2). The authors find that, for temperature over land, the model shows reasonable performance in reproducing the present-day climatology in both December–January–February(DJF) and June–July–August(JJA) in all the experiments. Meanwhile, cold biases prevail in both seasons, although portions of warm bias exist in DJF. For precipitation, the spatial pattern and amount, as well as seasonal evolution, are in general reproduced well in the experiments.Better performances of Tiedtke-1 and Tiedtke-2 are evident compared to Emanuel, particularly over ocean. Thereby, the optimal configuration of Reg CM4.7 for future climate change simulations over the region is identified as using the Tiedtke scheme with spray effects considered, along with the default settings for other physical parameterizations.

Needs of exploring the burden of recent onset seizures due to neurocysticercosis and challenges in southeast Asia focusing on scenario in Malaysia

Seizures due to neurocysticercosis(NCC) is a neglected human-to-human transmitted disorder and an emerging problem worldwide.A substantial portion of recent onset seizures is known to be attributed to NCC in Taenia solium(T.solium) endemic areas where populations which neither raise pigs nor eat pig meat are also at risk.High prevalence of NCC causing epilepsy has been reported in the underdeveloped areas of Southeast Asia(SEA) however,only fragmentary information on its incidence is available in countries like Malaysia.In Malaysia T.solium infection was previously thought to be infrequent due to Muslim population majority and the religious prohibition of consuming pork,but it is not totally absent There is an evident lack of knowledge and awareness of the actual burden,routes of transmission,and the impact of NCC in this region.The problem is assumed to be more prevalent particularly in cities because of the frequent inflow of possibly T.solium infected individuals or carriers among those who migrate from neighboring endemic countries to Malaysia.The issue of imported cases that are likely to be emerging in Malaysia is highlighted here.An accurate quantification of regional burdens of epilepsy due to NCC in Malaysia is warranted considering the disease emergence in its neighboring countries.It is suggested that the importance of NCC be recognized through quantification of its burden,and also to collect epidemiological data for its subsequent elimination in line of World Health Organization's mission for control of cysticercosis as a neglected tropical disease.In this review the need as well as a strategy for neurc-care center screening of epilepsy cases,and various issues with possible explanations are discussed.It is also proposed that NCC be declared as a reportable disease which is one of the eradicable public health problems in SEA.

Comparative genome analysis between Southeast Asian and South American Zika viruses

Objective:To understand the cause for the differences between potentially mild Southeast Asian and the more pathogenic ZIKV in South America.Methods:A comparative genomic analysis was performed to determine putative causations stemming from ZIKV.Results:Phylogcnctic analyses integrating geographical and time factors revealed that Southeast Asian ZIKV might not be the direct source of South American outbreaks as previously speculated.Amino acid residues unique to South American ZIKV isolates at the envelope,pr and NS1 proteins are listed and shown in the structural context.These unique residues on external viral proteins are not found in Southeast Asian ZIKV and could be responsible for the ongoing outbreak either via an intrinsic property of the virus or interactions with human immunity.Only a selected few primer/probe sets currently in clinical use were identified of being capable of detecting ZIKV strains worldwide.The envelope proteins of dengue virus(DENV) and ZIKV also showed a remarkable degree of similarity especially at the surface residues.Conclusions:findings that may help explain the cross-reactivity of DENV antibodies to ZIKV.Thus,major caveats must be exercised in using existing diagnostic tools for ZIKV.

Diversity and species-specificity of brood pollination of leafflower trees(Phyllanthaceae:Glochidion)by leafflower moths(Lepidoptera:Epicephala)in tropical Southeast Asia(Cambodia)

Glochidion(Phyllanthaceae;leafflower trees)is a genus of trees which is widely reported to be pollinated by leafflower moths(Gracillariidae:Epicephala)in temperate and subtropical Asia,Australia,and the Pacific islands.However,the pollination ecology of Glochidion is not well described from tropical Asia,the region where it is most species-rich at both local(<9 spp.)and regional(~200 spp.)scales.Here we report investigations of pollination biology and species-specificity of five Glochidion species in tropical Southeast Asia(Cambodia).Through nocturnal observations and fruit dissections,we find that at least three and likely five Glochidion species in Cambodia are pollinated by seed-parasitic leafflower moths.We find no evidence that any of these leafflower moths are non-mutualistic parasites,despite known examples of such parasites of this mutualism elsewhere in Asia.While the presence of a single larva in a fruit results in only a fraction of seeds being consumed,the presence of more than one larva per fruit-a frequent occurrence in some species—can result in almost all seeds within the fruit being infested.Multilocus phylogenetic analysis indicates that there are five different minimally monophyletic leafflower moth clades,each of which pollinates a unique Glochidion host species.Our results indicate that in its center of diversity in tropical Asia this system is an obligate pollination mutualism as previously described at the global margins of its distribution.These findings provide insights into the processes that generate and maintain biodiversity and maintain mutualism stability in plant-insect interactions in this biodiversity hotspot.

IMPACTS OF THE ONSET OF THE SOUTHEAST ASIAN SUMMER MONSOON ON THE BEGINNING OF THE RAINY SEASON IN YUNNAN

Summer monsoon in Southeast Asia can cause large-scale precipitation in the region in early summer, which is featured by prevailing low-level southwesterly from the Bay of Bengal to South China Sea （SCS）. It has characteristics of its own as well as those of Asian monsoons in general. As found in studies over recent years on East Asian monsoons, the earliest onset of the Southeast Asian summer monsoon occurs in early summer over the SCS, among all members of the monsoon system. It then advances westward to India and northward to eastern China, Japan and Korean Peninsula. As pointed out by Lau and Yang121, the end of April is the earliest time when the Asian monsoon sets up at the southern tip of Indo-china Peninsula. Being the earliest signal for the whole summer monsoon system in Asia, it may be of some predictive value for the establishment of Asian summer monsoon （ASM）.

Compilation of serial maps on karst geology of China and Southeast Asia

The compilation of serial maps of karst geology in China and Southeast Asia is a project under the 'One Belt One Road' geological survey plan granted by China Geological Survey. This paper summarized the research trend of geoscientific mapping in China and Southeast Asia and introduced the significance, contents, technical routes, operating methods and progress of the project. Through bilateral and multilateral cooperation, this project builded an international cooperation platform for mapping and completes the preliminary compilation of related karst geological maps in China and Southeast Asia, thus filling up the blank of karst geological maps in this region.

Compiling distribution of karst in Southern China and Southeast Asia

As China and Southeast Asian countries have accelerated and globalized their economic development, karst environmental problems have become increasingly prominent and studying on and compiling maps of karst geology is quite important. Therefore, based on a wide collection of data in Southeast Asian countries, a cooperative map compilation has been carried out internationally. Through comprehensive research and analysis, a unified understanding has been achieved in terms of compiling principles, contents and representing methods, Distribution of Karst in Southern China and Southeast Asia(1/5 000 000) has been compiled, which provides foundations for environmental protection and scientific studies of karst geology.

Metallogenic Characteristics of the Major Type Deposits in Southeast Asia

1 Introduction The Southeast Asia is endowed with a diversity of mineral resources(Khin Zaw et al.,2014).Tin,copper,nickel,bauxite,chromium and potash resources are widely distributed in the Southeast Asia,show considerable economic significance,have obvious complementarity to China,and is paid wide attention by Chinese geologists and mining industry in recent years.

Risk Management Strategies of Vulnerable Rural Households in Southeast Asia： A Case Study from Vietnam

In the Uplands of Southeast Asia, poor and near-poor farm households endure considerable livelihood vulnerability. Access to formal insurance services is scarce. Rural farm households in mountainous Northern Vietnam have developed alternative risk management strategies. This article investigates the theoretical links between poverty, vulnerability and risk. The concept of vulnerability to poverty lays the analytical framework. Based on empirical evidence from more than 200 ethnic minority households, major risks and risk management strategies are presented and analyzed. Results suggest that households suffer from limited endowment with and access to capital assets and service institutions. Human and economic risks （e.g. illness of family members and loss of livestock） were identified as the main components affecting rural livelihoods. Constrained access to adequate risk management strategies increase household＇s vulnerability, drowning them more and more in poverty. Major policy implications are that anti-poverty programs should focus on a broader target group, the currently poor as well as the vulnerable households.

The paleoclimate environment and recent sea level change on the seashores of Thailand Gulf in Southeast Asia

This paper analyzed and researched on several significant natural geological sections from the views of stratum-sequence stratigraphy,climate stratigraphy,event stratigraphy and regional stratigraphy by the investigation of Thailand,Malaysia and Singapore. In combination with the coupling relationship between the life-temperature of regional life zone and the evolution of geological environment,this paper exactly made out the geological sediment records of paleoclimate times in different time scales of 3 kaBP,1 kaBP and 0.5 kaBP since the past glacier age of Quaternary period,and it is consecutive and authentic for the material medium and time joint. These studies definitely reflected that the sea level of Thailand Gulf area is in tendency of continually dropping in recent years. They also provided important and new information for the global change analysis.

The Situation of Southeast Asia in 2017 and Assessment of Its Relations with China

The situation in Southeast Asia in 2017 was generally stable,as relations with China continued to improve,and progress in maritime consultations continued to develop.I.The political situation is stable and generally manageable Stability is manifested in the following aspects.The governments of the Philippines,Myanmar,Vietnam,Laos are seeking stability and good governance.