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Introduction: The South and Southeast Asia region has the second‐highest number of people living with HIV globally. Despite progress in reducing HIV incidence and AIDS‐related deaths, the region still has a long way to go in achieving the Joint United Nations Programme on HIV and AIDS (UNAIDS) 95‐95‐95 HIV testing, treatment and viral suppression targets. HIV self‐testing (HIVST) is recommended by the World Health Organization as an additional approach to HIV testing. This paper provides a commentary on the implementation status, benefits, barriers and recommendations for HIVST implementation in South and Southeast Asia. Additionally, it presents perspectives from HIV testing service experts from 11 countries in the region to put forth recommendations to accelerate the implementation of HIVST in South and Southeast Asia. Discussion: There is uneven progress in national HIVST policy development and implementation across the region. HIVST, as an additional testing approach, can help to enhance testing coverage, frequency and demand for follow‐up HIV services among key populations. Key factors influencing the implementation and scale‐up of HIVST include the degree of awareness of HIVST among general and key populations, the development and implementation of supportive national HIVST policies and the availability of public funding for HIVST. To address barriers and leverage enablers to HIVST implementation, generating evidence on cost‐effectiveness and budget impact, developing multisectoral partnerships for market shaping, promoting differentiated and decentralized delivery models, and optimizing linkage to further testing and care are recommended. Conclusions: It is crucial to accelerate the implementation and scale‐up of HIVST to differentiate and decentralize the delivery of HIV testing services in South and Southeast Asian countries. Sharing experiences among country experts is vital to foster the adoption of best practices and facilitate the trial‐and‐error process of HIVST implementation. Such collaborative approaches can help South and Southeast Asian countries attain the UNAIDS 95‐95‐95 targets, especially the first 95 on HIV diagnosis, and play a significant role in ending the global AIDS epidemic. [ABSTRACT FROM AUTHOR]

In 2019, the United Nations (UN) promulgated the Global Compact for Safe, Orderly and Regular Migration which charts the UN's global migration policy strategy, affording central importance to safety in migration. This ascendant focus on safe migration is echoed in a range of national and regional policy initiatives. Despite the policy enthusiasm for safe migration, to date, there is a dearth of critical scholarly attention to this policy shift. This paper builds on 7 years of ethnographic research on safe migration interventions in mainland Southeast Asia. Centring on the Mekong region, this paper examines two interlocking effects of safe migration policy instrumentalisation. On the one hand, safe migration discourse' spatio‐temporal underpinnings dispositions programmes to gravitate towards policy abstractions. Yet, in practice, safe migration interventions heavily depend on informal constellations of sociality, where migrants become re‐embedded as both objects and instruments of policy. [ABSTRACT FROM AUTHOR]

This paper examines how Chinese transnational investments, as (re)framed in the Belt and Road Initiative (BRI), contribute to changes in urbanisation processes in Southeast Asia. On the ground, the BRI becomes contextualised and intersects with local and national development trajectories. The growing presence of Chinese actors in the region intensifies urban dynamics, especially in secondary cities and emerging urban sites, where the BRI is used as a lever for local internationalisation strategies. The heterogeneous nature of the links between the BRI and various large urban projects is demonstrated on the basis of case studies involving changing consortia of private and public Chinese and Southeast Asian actors. A regional approach allows us to identify connections and shared processes across Southeast Asian countries. It provides a historically grounded understanding of how the BRI incorporates long‐term interactions with China and more recent partnerships in Southeast Asian countries. The paper paves the way for a research agenda that contests the image of China as a monolithic actor implementing the BRI uniformly and consistently. Further analyses are needed to examine systems and networks of actors as well as the local urban politics that affect the BRI on the ground. [ABSTRACT FROM AUTHOR]

The production of illicit synthetic drugs has undergone a significant shift from China to the Golden Triangle, profoundly impacting Southeast Asia's legal systems, drug enforcement and public health. This paper reviews the production, distribution and use of illicit synthetic drugs in the region, explaining their alignment with regulatory policies in China and Southeast Asia. The public health effects resulting from the increased production and use of synthetic drugs in Southeast Asia are reviewed, emphasizing the importance of public health protections such as harm reduction, treatment and rehabilitation. This study also discusses legal mechanisms to enhance control over illicit drug activities, mainly compound‐wide legislative prohibitions targeting present and future fentanyl and methamphetamine analogues. Moreover, it underscores the urgency for collaborative efforts between China and Southeast Asian states to mitigate the influence of Chinese cartels operating in the region. By elucidating the multifaceted challenges posed by the shifting drug production landscape, this paper highlights the importance of a comprehensive approach encompassing regulatory, law enforcement and public health measures. [ABSTRACT FROM AUTHOR]

This paper presents a sample selection model with spatial correlation in the selection and outcome variables and studies the maximum likelihood method of estimation. Consistency and asymptotic normality of the maximum likelihood estimator are established by the spatial near‐epoch dependent properties of the variables. Monte Carlo simulations show its good finite‐sample performance. This model is used to examine the impact of climate change on cereal yields in Southeast Asia and projects that climate change may cause a reduction in cereal yields by 7%$$ 7\% $$ (31%$$ 31\% $$) in the minimum‐change (maximum‐change) scenario. [ABSTRACT FROM AUTHOR]

This paper applies optimum currency area (OCA) theory to Southeast Asia to assess the potential for a monetary union in that region. We construct a panel of 10 Southeast Asian countries over the period 1990–2018 and apply the dynamic OLS estimator to quantify the costs and benefits of a potential OCA. A possible monetary union in Southeast Asia is vulnerable to asymmetric shocks, although the degree of specialisation has decreased and the openness index increased. Estimates confirm that both OCA criteria favour an increase in the region's income and FDI inflows and a reduction of its unemployment rate. However, inadequate labour mobility and stagnating intra‐trade shares are major obstacles in this regard, but if addressed they could benefit economic development and GDP per capita in the ASEAN region. We conclude that Southeast Asia is far from being an optimum currency area, but if it were to form a common currency area, the loss of economic sovereignty and its costs would be more than offset by the resulting monetary efficiency gain. [ABSTRACT FROM AUTHOR]

Moisture sources and transport processes play a critical part in hydrological cycle and determine regional precipitation. This paper utilizes the Water Accounting Model‐2layers (WAM‐2layers) and the ERA5 reanalysis data to track the sources of precipitation over the Pearl River Basin (PRB). The contribution of external moisture and the role of local recycling are investigated. The results show that during the period from 1980 to 2020, oceanic sources including the western North Pacific and Indian Oceans serve as the primary moisture sources of precipitation over the PRB. The contributions to total seasonal precipitation are respectively 62.57% in MAM, 54.79% in JJA, 43.70% in SON and 60.88% in DJF. By contrast, the contribution of local recycling is generally below 5.50%. In the dry years of 1994, 1997 and 2001, the contribution of terrestrial sources is about 19.22%; in the wet years of 1989, 2009 and 2011, the contribution is about 16.31%. The summer precipitation anomalies are mainly attributable to moisture anomalies from the Equatorial Indian Ocean in the wet years and from Southeast Asia in the dry years. Furthermore, vertically integrated moisture flux anomalies over the boundaries of the PRB are generally the result of anomalous wind rather than anomalous moisture. In the wet years, low‐pressure systems induce strong cyclonic moisture transports, increasing the PRB precipitation. In the dry years, high‐pressure anomalies over the PRB block the moisture transports from the Indian Ocean and western North Pacific. [ABSTRACT FROM AUTHOR]

This paper reviews the trends and driving forces for the relatively recent growth in cross‐national marriages in East and Southeast Asia with a specific focus on the experiences of female marriage migrants from Southeast Asia. It explicates the various forms of inequality faced by the low‐income marriage migrant women including gender power dynamics within the household, socioeconomic inequalities, integration into the destination society, and intergenerational transfer of inequalities. We acknowledge that the inequality experienced by marriage migrant women results from a complex web of intersecting social‐cultural, political, and economic forces occurring in Asia in the past three decades. As a result of rising female educational attainment and the practice of marriage hypergamy in Asia, an increasing number of low socioeconomic‐status men from developed countries seek marriage partners abroad from lower‐income and less‐developed countries. Upon entering the cross‐national marriage market, many low‐income migrant women face multiple disadvantages in the host country due to inadequate socioeconomic support, language barriers, social stigma on foreign brides, and a lack of legal status. These inequalities exacerbate their initial disadvantages to perpetuate a vicious cycle of intergenerational disadvantages for their offspring. We conclude with a critique of extant literature and identify promising future research directions. [ABSTRACT FROM AUTHOR]

This paper presents evidence for hypomineralization disorders (rickets and osteomalacia) in non‐adults at Man Bac, a Neolithic site from northern Vietnam dated to 4000–3500BP, contributing to the well‐described disease burden at the site that includes scurvy, treponemal disease, thalassemia, and malaria. Forty‐four non‐adults (<20 years of age‐at‐death) were assessed for macroscopic and radiographic evidence for hypomineralization disorders. Differential diagnosis was completed using traditional methods and three‐level standardized criteria to combat the challenges of overlapping pathological features between hypomineralization disorder and the other diseases already diagnosed at the site. In addition, a diagnostic certainty approach was applied to investigate the impact of lesion ambiguity on our findings. Kaplan–Meier and Fishers exact tests were applied to assess age‐at‐death‐related epidemiological patterns of hypomineralization disorder and co‐morbid relationships with scurvy, thalassemia, and treponemal disease. Almost 50% of the non‐adult assemblage presented with evidence for hypomineralization disorder, which was associated with decreased survivorship in childhood. Potential epidemiological relationships between scurvy and hypomineralization disorders, and thalassemia and hypomineralization disorders are described. The former relationship may be due to the likelihood of the introduction of rice resulting in multi‐micronutrient deficiency, including vitamin C and calcium deficiency, and cultural attitudes to sunlight. The latter relationship may relate to the pathophysiology of thalassemia that can result in secondary osteomalacia possibly contributing to the development of hypomineralization disorder in the thalassemic non‐adults. The findings are significant as they present possible approaches for diagnosis of disease embedded within complex disease burdens where individuals are likely suffering from co‐morbidities. [ABSTRACT FROM AUTHOR]

This paper examines the changes of El Niño–Southern Oscillation (ENSO) associated winter rainfall relationship in Southeast Asia (SEA) in the historical period (1981–2010) and future period (2071–2100) based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) models simulations. Twenty general circulation models (GCMs) are chosen from the Scenario Model Intercomparison Project (ScenarioMIP) highest emission scenario—Shared Socioeconomic Pathway (SSP) 5‐8.5. This study focuses only on the GCMs that have been able to replicate the consistent associated patterns observed, referred to as "teleconnection‐consistent models" (TCMs). During historical period, ENSO has significant negative association with SEA winter rainfall, particularly over Indochina mainland, Maritime Continent (MC) and northern Borneo. The significant negative‐associated teleconnection affected area has increased under future climate, particularly over southern part of South China Sea (SCS). The weakening of south westerlies at Western North Pacific (WNP) centred near 20°N reduces the moisture transport from Indochina into south of China, increase the negative correlated affected area in the SEA regions above equator. The northeasterlies/easterlies that prevailed from the WNP anticyclone (AC) brings significant moisture flux into southern Borneo, causing increment of significant positive‐associated moisture flux convergence to that region. The weakening of upward motion in TCM results in less warm and moist air rising over SEA MC, reducing the rainfall availability. The 1° eastward expansion of WC downward branch eastern edge leads to suppression of convective activities, increasing the dry affected area. The results suggest that the ENSO has a larger influence on the negative‐associated SEA rainfall and atmospheric circulation in the December–January–February (DJF) late‐21st century when compared to the 1980–2010. [ABSTRACT FROM AUTHOR]

The Low lAtitude long Range Ionospheric raDar (LARID), which consists of two high frequency (HF) radars looking toward the east and west of Hainan Island, respectively, has been developed and installed at Dongfang (19.2°N, 108.8°E, dip lat. 13.8°N), China. This paper describes the system design of LARID and its first observational results of equatorial plasma bubble (EPB) irregularities. The antenna array of LARID is composed of a west‐looking array and an east‐looking array. Each array consists of 20 log‐periodic antennas for transmission and reception and 4 log‐periodic antennas for interferometry, and has a beam steering capability in the azimuth angles of ±24° due the boresight pointing east (or west). Observational results show that the LARID is capable of detecting backscatter echoes from EPB irregularities and the ground, with a distance of 4,000 km or more away from Hainan Island. Multiple EPB structures were continuously observed on 17 April 2023, with eastward drifts ranging between 70 and 130 m/s. Based on ray tracing simulations, the backscatter echoes of EPB irregularities were due to the 0.5‐hop and 1.5‐hop propagation modes. The distances between the successive EPB structures were estimated ranging between 500 and 900 km in longitude. The LARID observations, together with other instruments in the East and Southeast Asian sector, provided a clear picture of longitudinal variation of EPBs in 90–125°E. It is expected that the LARID will provide an important tool to study the generation and evolution of EPBs and their short‐term prediction in East and Southeast Asia. Key Points: A Low lAtitude long Range Ionospheric raDar (LARID) operating at 8–22 MHz has been developed and installed at Hainan Island, ChinaFirst long‐range observations of equatorial plasma bubble (EPB) irregularities and their zonal drifts by the LARID were presentedThe LARID is expected to play an important role in the study of EPB and its short‐term forecasting in East and Southeast Asia [ABSTRACT FROM AUTHOR]

Secularization, expansion of higher education, and urbanization have led to disenchantment with politics and the erosion of political trust in many societies. Religion may continue to be salient, however, how these forces interact with enduring religious influences to shape political trust is unclear. This paper examines the issue using Asian Barometer Survey (2001–2016) data with hierarchical age–period–cohort (HAPC) models. Our results show supportive evidence for the following findings: in East and Southeast Asia, urbanization is associated with less political trust for most religions except Islam; education is associated with less political trust; education's effect is the most salient for the atheists and Buddhists, but it disappears among the Muslims. The findings suggest the power of modernization and secularization significantly differs across cultures and religions. We should not simply perceive religion as a universally conservative force; instead, we need to understand religions through an integrated macro‐micro perspective by situating it in the social contexts. [ABSTRACT FROM AUTHOR]

The impact of global warming on lightning flash rates remains relatively unknown. In this study, the South China Sea (SCS) and the surrounding areas within Southeast Asia were selected to examine the long‐term trend and future projection of lightning activity based on the currently longest satellite‐based lightning data set available and climate models. Our study revealed a reduction in the observed lightning flash rates around the SCS, with a linear trend of −0.11 fl km−2 yr−2 during 1996–2013. In contrast, the precipitation around the SCS exhibited an increasing trend and was negatively correlated with the local lightning flash rate. The sea surface temperature gradient over equatorial Pacific Ocean, latent heat flux over the equatorial Indian Ocean, local convective available potential energy, precipitation and aerosol changes collectively accounted for 82% of the variance in the lightning fluctuations over the SCS and Southeast Asia. Multiple linear regression proxies of lightning flash rates were constructed and applied to the climate models. The models indicated that lightning activity around the SCS is projected to intensify by 10% and 12% by the end of the 21st century under SSP245 and SSP370, respectively. Plain Language Summary: The projection of future changes in lightning activity is uncertain owing to various factors, and different regions exhibit distinct trajectories. In this study, the focus was on the South China Sea (SCS) and Southeast Asia, and past variations in lightning activity was examined and used to predict future variations in lightning activity. Employing a multiple linear regression approach, we identified the large‐scale thermodynamic drivers and local environmental factors that influence lightning activity around the SCS. The research findings indicated a reduction in lightning activity over the past few decades over the SCS and Southeast Asia region. The simulation results indicate that in the future under ongoing global warming, regional lightning activity will intensify. Key Points: Lightning activity and precipitation show opposing regional trends around the South China Sea (SCS)Remote thermodynamic and local environmental factors both contribute to the variability in lightning around the SCSUnder future climate change scenarios, lightning activity around the SCS is projected to gradually increase [ABSTRACT FROM AUTHOR]

Anthropogenic activity drives extensive tropical deforestation, particularly in Southeast Asia where 16% of total forest cover was lost between 2000 and 2020. While land surface changes significantly affect the atmosphere, their net impact on convective clouds is not well‐constrained. Here, we use satellite data to demonstrate long‐term deforestation in Southeast Asia robustly alters cloud properties and provide the first observational evidence that the magnitude of this response depends on the atmospheric environment. Deforestation drives a shift toward more widespread, shallower clouds during the daytime, with amplified effects in dry inland areas compared with moist coastal regions. Aerosols only weakly modulate the cloud fraction response, but offset the cloud top height response to deforestation, suggesting the influence of aerosol indirect effects. We conclude that the local signature of forest loss is not uniform, and regional differences in climatology must be considered when assessing deforestation impacts on clouds and the climate system. Plain Language Summary: Humans are driving widespread deforestation in the tropics. Changes to the land surface following forest loss are generally known to affect the atmosphere, but it is hard to tell how deforestation will impact clouds in a given area. Here, we focus on Southeast Asia, a region of the world facing dramatic large‐scale deforestation. We use two decades of satellite data to estimate how the loss of tropical forests impacts cloud properties. On average, we find that deforestation leads to more widespread and shallower clouds. We then look further into how this cloud response to deforestation depends on other environmental factors like moisture and aerosols. This gives us a better idea of which regions are most sensitive to changes in forest cover. Overall, our results show there is an observable cloud response to deforestation, but this response may be stronger in some regions than in others depending on underlying moisture and aerosol conditions. As forest loss continues in Southeast Asia and across the world, it is important to further study these region‐dependent interactions between the atmosphere and the land surface so we can better understand the impacts of human‐driven deforestation on weather and climate. Key Points: Deforestation in Southeast Asia drives a robust shift toward more widespread and shallower clouds on an annual timescaleThis effect has been debated in modeling studies, but we demonstrate this observationally using two decades of satellite dataSome regions are especially vulnerable to deforestation‐driven changes in clouds, depending on atmospheric moisture and aerosol loading [ABSTRACT FROM AUTHOR]

Subduction initiation in oceans is key to understanding regional and global plate tectonics and ocean basin dynamics; however, its genetic mechanism is still enigmatic. The most famous model that predicts intraoceanic subduction initiation along transform faults or fracture zones (i.e., the Subduction Initiation Rule) has been widely used to explain arc‐like geochemical signatures within the Neo‐Tethyan ophiolites, but fails to account for the speculation and/or calculation of a sub‐parallel relationship between the Jurassic subduction zones and paleo ridges of the western Neo‐Tethys. Here, we propose a ridge‐parallel detachment fault‐hosted subduction re‐initiation model for the Jurassic western Neo‐Tethys. Based on field geological and geochemical evidence, we show that the Refahiye ophiolite in the İzmir–Ankara–Erzincan suture of northern Turkey has diagnostic characteristics indicative of (ultra)slow seafloor spreading. An (ultra)slow‐spreading nature also characterizes many Neo‐Tethyan ophiolites from the Alps to Southeast Asia, either at mid‐ocean ridges or in suprasubduction zones. Due to its extremely weak nature, detachment faults were probably a key candidate for the Jurassic intraoceanic subduction re‐initiation of the western Neo‐Tethys in response to far‐field compression after its long‐lived northward subduction. This model is applicable to both the Jurassic and Early Cretaceous ophiolites, but is questionable for the Late Cretaceous ophiolites. Its utility deponds on the kinematics of ancient plate boundaries and compositions of ophiolites. The detachment fault‐hosted subduction re‐initiation model can explain the arc‐like geochemical features of the Jurassic western Neo‐Tethyan ophiolites, but its effect on the structure and component of ophiolites is diverse. Plain Language Summary: Subduction of oceans is key to understanding regional and global plate tectonics. However, where and how ocean subduction initiates (i.e., subduction initiation) is still enigmatic, in particular for those vanished oceans in Earth's geologic history. In this study, we propose a new model of ridge‐parallel detachment fault‐hosted subduction re‐initiation for the western Neo‐Tethys Ocean in the Jurassic. Based on this study and a global compilation, we show that the ophiolites along the Neo‐Tethyan orogenic belt commonly contain slow‐ and ultraslow‐spreading oceanic lithospheres, either formed at mid‐ocean ridges or in suprasubduction zones. As for the western Neo‐Tethys, detachment faults adjacent to the paleoridges may have served as key candidates for subduction re‐initiation after the long‐lived northward subduction in the early stage, rather than along transform faults or fracture zones as previously suggested. This new model provides alternative explanations for the geochemical and structural diversities of the western Neo‐Tethyan ophiolites, and its utility in global ophiolites needs further examination. Key Points: The Neo‐Tethyan Refahiye ophiolite in northern Turkey formed at an (ultra)slow‐spreading ocean basin, probably at mid‐ocean ridgesDetachment fault is a key candidate for the Jurassic subduction re‐initiation of the western Neo‐Tethys OceanThe utility and diversity of detachment fault‐hosted subduction re‐initiation is discussed for the origin of Neo‐Tethyan ophiolites [ABSTRACT FROM AUTHOR]

Following the termination of seafloor spreading in the South China Sea (SCS) basin, abundant intraplate volcanism widely spreads in the Indochina block, SCS basin, and Leiqiong area, forming the Southeastern Asian Basalt Province (SABP). The geodynamic origin of the SABP has long been enigmatic and debated. Here, we present a high‐resolution 3‐D upper mantle S‐wave velocity model in the region by conducting earthquake‐based surface wave tomography with seismic data collected across Southeast Asia. The resultant images depict a plume‐like structure beneath the central area of the SABP, characterized by a continuous, sub‐vertical low‐velocity column in the upper mantle. Our new findings, combined with previous geochemical and geodynamic evidence, suggest that the extensive post‐spreading intraplate volcanism within the SABP is likely induced by this focused mantle upwelling, which could be further traced down to the core‐mantle boundary as inferred by existing global velocity models. Plain Language Summary: The well‐known Southeastern Asian Basalt Province (SABP), which covers an extensive area of the South China Sea (SCS) and surroundings, is characterized by voluminous volcanism after the cessation of seafloor spreading in the SCS basin. However, the geodynamic mechanism responsible for the formation of the SABP remains debated and not well understood. In this study, we build a high‐resolution 3‐D seismic velocity model in the region utilizing multiple sources of seismic data collected throughout Southeast Asia. We find a distinct plume‐shaped low‐velocity anomaly in the upper mantle beneath the central region of the SABP. Combining with previous geochemical and geodynamic research results, we interpret that the abundant intraplate volcanism within the SABP may be contributed by the underlying focused mantle upwelling. This mantle upwelling, as evidenced in previous global seismic velocity models, could be further traced down to the core‐mantle boundary (∼2,900 km below the Earth's surface). Our tomographic images provide valuable insights into the origin and mantle dynamics related to the young intraplate volcanism that occurred in Southeast Asia. Key Points: A high‐resolution 3‐D upper mantle S‐wave velocity model surrounding the South China Sea is constructedA continuous, low‐velocity column is imaged beneath the central region of the Southeastern Asian Basalt ProvinceThe post‐spreading intraplate volcanism within the Southeastern Asian Basalt Province is likely induced by the focused mantle upwelling [ABSTRACT FROM AUTHOR]