Using seawater for toilet flushing effectively reduces the consumption of precious freshwater resources, yet it introduces bromide and iodide ions into a wastewater treatment system, which may form ...bromo- and iodo-disinfection byproducts (DBPs) during chlorination of the wastewater effluent. Most of the newly identified DBPs in chlorinated wastewater effluents were halophenolic compounds. It has been reported that the newly identified bromo- and iodo-phenolic DBPs were generally significantly more toxic to a heterotrophic marine polychaete than the commonly known haloacetic acids and trihalomethanes. This has raised a concern over the discharge of chlorinated saline wastewater effluents into the marine ecosystem. In this study, the toxicity of new halophenolic DBPs and some haloaliphatic DBPs was tested against an autotrophic marine alga, Tetraselmis marina. The alga and polychaete bioassays gave the same toxicity orders for many groups of halo-DBPs. New halophenolic DBPs also showed significantly higher toxicity to the alga than the commonly known haloacetic acids, indicating that the emerging halophenolic DBPs deserve more attention. However, two bioassays did exhibit a couple of disparities in toxicity results, mainly because the alga was capable of metabolizing some (nitrogenous) halophenolic DBPs. A quantitative structure-toxicity relationship was developed for the halophenolic DBPs, by employing three physicochemical descriptors (log K(ow), pKa and molar topological index). This relationship presented the toxicity mechanism of the halophenolic DBPs to T. marina and gave a good prediction of the algal toxicity of the tested halophenolic DBPs.
Through a case study of China, one of the largest emigration states and a rising global power, this article probes how a homeland state envisions diaspora politics amid geopolitical transformations. ...Drawing on historical, policy, and interview data, I argue that China's changing positioning toward Chinese emigrants, triggered by the state's geopolitical vicissitudes, has reshaped and repurposed diaspora institutions. I find that since the 2010s, China's diaspora policies have shifted away from soliciting diasporic support for domestic economic growth and national unification and toward liaising externally with migrants to expand Chinese soft power abroad. In consequence, diaspora institutions with more extensive overseas connections and flexible working experiences have taken precedence over formal state agencies specialized in domestic policymaking. This article makes two theoretical contributions to a multilevel understanding of diaspora politics as traversing simultaneously the domestic and global political fields. First, following neo-pluralism, I examine China's diaspora bureaucracy as composed of a diverse set of state entities with distinctive, or even contradictory, interests, orientations, and philosophies. These organizational variations shape diaspora institutions’ different strengths and fluctuating significance in China's shifting geopolitical strategies. Second, by situating emigrants and diaspora institutions in the macrohistorical framework of world politics, this article pushes research on diaspora politics into more profound dialog with world-systems theory. Rather than assuming an asymmetric interdependence between weaker emigration countries and hegemonic immigration countries, I demonstrate how an aspirational homeland state seeks to challenge this established world order and accomplish its geopolitical ascendancy through diaspora re-strategizing and institutional reshuffling.
International student migration/mobility (ISM) has long come under the spotlight in migration and education studies. Previous research has focused primarily on inbound students in Western host ...countries, with much less attention on sending countries’ policies. Based on evidence from interviews, ethnography, and policy analysis in China, the world’s largest source country of student migrants, I argue that outbound student migration can be integrated into the home country’s broader diaspora politics to serve economic, governmental, and geopolitical policy objectives. These diverse, sometimes-clashing, interests are predicated upon China’s domestic politics and global positioning. To establish a conceptual bridge between ISM and diaspora studies, I depart from the mobility paradigm’s emphases on neoliberalism and de-regulation and, instead, foreground nation-states’ changing, yet-unabating, interests in regulating and strategizing about overseas students. I find that following decades of prioritizing the economic and governmental impacts of student returnees (haigui, or colloquially “sea turtles”) in boosting the domestic economy and maintaining political stability, China now attaches growing importance to student migrants’ geopolitical value as “grassroots ambassadors” (minjian dashi) in expanding China’s global influence and enhancing its national image abroad. This geopolitics-focused national reorientation, however, may not be well received by student migrants themselves or fully implemented by street-level migration bureaucrats. By examining tensions between the central Chinese state, student migrants, and frontline local officials, this article sheds new light on ISM as a dynamic policy arena where state ambitions crosscut individual desires and national grand plans are confronted with flexible local improvisation.
High-resolution palynological analysis on annually laminated sediments of Sihailongwan Maar Lake (SHL) provides new insights into the Holocene vegetation and climate dynamics of NE China. The robust ...chronology of the presented record is based on varve counting and AMS radiocarbon dates from terrestrial plant macro-remains. In addition to the qualitative interpretation of the pollen data, we provide quantitative reconstructions of vegetation and climate based on the method of biomization and weighted averaging partial least squares regression (WA-PLS) technique, respectively. Power spectra were computed to investigate the frequency domain distribution of proxy signals and potential natural periodicities. Pollen assemblages, pollen-derived biome scores and climate variables as well as the cyclicity pattern indicate that NE China experienced significant changes in temperature and moisture conditions during the Holocene. Within the earliest phase of the Holocene, a large-scale reorganization of vegetation occurred, reflecting the reconstructed shift towards higher temperatures and precipitation values and the initial Holocene strengthening and northward expansion of the East Asian summer monsoon (EASM). Afterwards, summer temperatures remain at a high level, whereas the reconstructed precipitation shows an increasing trend until approximately 4000 cal. yr BP. Since 3500 cal. yr BP, temperature and precipitation values decline, indicating moderate cooling and weakening of the EASM. A distinct periodicity of 550–600 years and evidence of a Mid–Holocene transition from a temperature-triggered to a predominantly moisture-triggered climate regime are derived from the power spectra analysis. The results obtained from SHL are largely consistent with other palaeoenvironmental records from NE China, substantiating the regional nature of the reconstructed vegetation and climate patterns. However, the reconstructed climate changes contrast with the moisture evolution recorded in S China and the mid-latitude (semi-)arid regions of N China. Whereas a clear insolation-related trend of monsoon intensity over the Holocene is lacking from the SHL record, variations in the coupled atmosphere-Pacific Ocean system can largely explain the reconstructed changes in NE China.
•Holocene vegetation and climate dynamics in NE China are studied.•Climate shifts are revealed through palynology and biome/climate reconstructions.•Asynchronous maximums in the Holocene summer temperature and monsoon precipitation.•Pacific sea ice extent and sea surface temperatures influence climate in NE China.
International migration profoundly reshapes the urban landscape in sending and receiving countries. Compared to ethnic enclaves in migrant-receiving metropolises and remittance houses in sending ...communities, we know little about systematic urban changes led by emigration states. In this article, based on three months of fieldwork in a migrant hometown in China, I argue that the dispersion of emigrants per se does not make its urban space inherently 'diasporic'. Rather, a 'diasporic place' can be strategically constructed by local sociopolitical actors, a process I conceptualise as 'diasporic placemaking'. To create an international city branding and boost the consumption-based urban economy, the local state promotes Western architectural forms and imagines globalisation as a new way of life. To understand how migrants and local residents make sense of diasporic placemaking, I analyse deep-running tensions between their diverse self-perceptions and state construction. Instead of an innocent project, diasporic placemaking is replete with ambitions, achievements, and anxieties in post-socialist China's march towards modernity, progress, and prosperity. To advance the constructivist momentum in diaspora studies, I explore how diaspora construction is realized and contested in urban transformations while shedding light on how migrant spaces are valorised and performed by local actors for economic and symbolic purposes.
We study the derivative nonlinear Schrödinger equation for generic initial data in a weighted Sobolev space that can support bright solitons (but exclude spectral singularities). Drawing on previous ...well-posedness results, we give a full description of the long-time behavior of the solutions in the form of a finite sum of localized solitons and a dispersive component. At leading order and in space-time cones, the solution has the form of a multi-soliton whose parameters are slightly modified from their initial values by soliton–soliton and soliton–radiation interactions. Our analysis provides an explicit expression for the correction dispersive term. We use the nonlinear steepest descent method of Deift and Zhou (Commun Pure Appl Math 56:1029–1077,
2003
) revisited by the
∂
¯
-analysis of McLaughlin and Miller (IMRP Int Math Res Pap 48673:1–77,
2006
) and Dieng and McLaughlin (Long-time asymptotics for the NLS equation via dbar methods. Preprint,
arXiv:0805.2807
,
2008
), and complemented by the recent work of Borghese et al. (Ann Inst Henri Poincaré Anal Non Linéaire,
https://doi.org/10.1016/j.anihpc.2017.08.006
,
2017
) on soliton resolution for the focusing nonlinear Schrödinger equation. Our results imply that
N
-soliton solutions of the derivative nonlinear Schrödinger equation are asymptotically stable.
Scholars have long debated whether international migration impinges on states' control over transborder populations. In this article, I lay bare how states consolidate control through the calculated ...manipulation of emigrant citizenship. Based on a genealogical interrogation of China's emigrant citizenship policies from the 1950s to present and three months of fieldwork in an emigrant community in China, I illustrate that the state first revokes emigrants' citizenship and then imposes selective conditions on its restoration upon their return. China's otherwise domestically oriented citizenship regime, namely, the household registration (hukou) system, works similarly as an international immigration regime by selecting and documenting potential citizens. My study sheds new light on the understudied external control of the hukou system by examining how it limits emigrants' right of resettlement and proscribes overseas dual residency. I argue that citizenship is anything but an enduring, unproblematic demographic fact. It is, in essence, a revocable, precarious politico-legal accomplishment. These malleable processes enable the state to redefine the citizenship of absent and returned members, reinsert the congruence between nationality and residency, and reinforce control over transborder populations. These findings may have implications for similar mechanisms of governing international migrants through documentation and legal codification beyond China.
Lexical features are influenced by different languages and genres. The study of lexical features in different genres of texts on the same topic is helpful to understand the universalities and ...peculiarities of languages. This study constructs a research on the lexical feature and word collocations of two self-build corpora (China's economic Legal Policy Corpus and English News Corpus during the COVID-19 pandemic), the methods of Quantitative Linguistics and context interpretation are adopted. It was found that: (1) the word length, word frequency, word cluster and high frequency word distribution in English economic news and Chinese economic legal policies are influenced by language and genre to some extent, and they conform to different functional image distribution; (2) during the COVID-19 pandemic, “development” has been the focus of China's economic legal policies and English news, the two have attached importance to economic recovery and taken a positive attitude toward it in different ways. These findings suggest that: (1) There are some universalities and peculiarities between English economic news and Chinese economic legal policies in the distribution of lexical feature; (2) there is a certain synchronization between laws and news, and both of them maintain a positive and objective attitude toward the economic development during the pandemic. This study carries out a macroscopic investigation on internal structure and external interpretation, which enriches the study on lexical features and cultural features of language and provides some references for relevant studies.
The burgeoning field of immobility studies focuses on how migratory aspirations and capabilities shape a given (im)mobility status but devotes scant attention to how people traverse different ...(im)mobility categories. Through a case study of Chinese students in the United States during the COVID-19 pandemic, this article develops two arguments to shed light on migrants’ experiences and strategies in mobility transitions. First, during the pandemic, while China's restrictive travel policies and unfavorable public discourses made return migration extremely difficult, Chinese overseas students also felt unwelcome in the United States, due to visa restrictions and Sinophobic violence. This dilemma of being unable to return to the homeland and being simultaneously stranded in a hostile host society pushed Chinese student migrants, a previously highly mobile population, into immobility. Second, drawing on in-depth interviews, we discover that Chinese overseas students deployed four sets of tools—online crowdsourcing, virtual intermediary, temporal adaptation, and institutional cushioning—to reclaim mobility. We propose the concept of “mobility repertoires” to capture social actors’ active retooling and deliberate restrategizing of digital, cognitive, and institutional resources to navigate unsettling (im)mobility predicaments and construct new mobility tactics. By cross-fertilizing studies of immobility and migration infrastructure, we provide an action-centered, processual account of (im)mobilities as agential practices and robust courses of action, rather than static statuses or categories. This article also transcends the mobility bias in the literature on international student mobility (ISM) by unraveling the co-production of international student immobility by migration policies and discursive constraints in host and home countries.
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•Increasing global offshore pollution as a worldwide problem.•Coastal geological disasters due to global offshore pollution.•Complex offshore sedimentary dynamics through long-term ...accumulating pollutants.•The stable succession and development trend of marine ecosystems was significantly interrupted.
Populations and metropolitan centers are accumulated in coastal areas around the world. In view of the fact that they are geographically adjacent to coasts and intense anthropogenic activities, increasing global offshore pollution has been an important worldwide concern over the past several decades and has become a very serious problem that needs to be addressed urgently. Due to offshore pollution, various geological disasters occur in high frequency, including intensified erosion and salinization of coastal soils, frequent geological collapses and landslides and increasing seismic activities. Moreover, offshore pollution shows increasingly serious impacts on the topography and geomorphology of offshore and coastal areas, including coastal degradation, retreating coastlines and estuary delta erosion. Offshore sedimentation processes are strongly influenced by the pH changes of terrestrial discharges, and sedimentary dynamics have become extremely acute and complex due to offshore pollution. The seabed topography and hydrodynamic environment determine the fate and transport of pollutants entering offshore regions. Coastal estuaries, port basins and lagoons that have relatively moderate ocean currents and winds are more likely to accumulate pollutants. Offshore regions and undersea canyons can be used as conduits for transporting pollutants from the continent to the seabed. It is particularly noteworthy that the spatial/temporal distribution of species, community structures, and ecological functions in offshore areas have undergone unprecedented changes in recent decades. Due to increasing offshore pollution, the stable succession and development trend of marine ecosystems has been broken. It is thus important to identify and regulate the quantity, composition and transportation of pollutants in offshore regions and their behavior in marine ecosystems. In particular, crucial actions for stabilizing marine ecosystems, including increasing species and biodiversity, should be implemented to enhance their anti-interference capabilities. This review provides an overview of the current situation of offshore pollution, as well as major trends of pollutant fate and transportation from continent to marine ecosystems, transformation of pollutants in sediments, and their bioaccumulation and diffusion. This study retrospectively reviews the long-term geological evolution of offshore pollution from the perspective of marine geology, and analyses their long-term potential impacts on marine ecosystems. Due to ecological risks associated with pollutants released from offshore sediments, more research on the influence of global offshore pollution based on marine geology is undoubtedly needed.
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