Abstract Different adverse health effects of submicron (PM1) and fine particles (PM2.5) may be attributed to their chemical differences, requiring a better understanding of size-resolved composition. Herein, extensive online measurements were conducted across seasons in Beijing by two aerosol mass spectrometers, one of which alternately sampled PM1 and PM2.5. Source apportionment of organic aerosol (OA) indicated that traffic- and cooking-related OA together accounted for ∼20%−30% of the OA mass in PM2.5, showing insignificant seasonal variations. Coal-combustion and biomass-burning-related OA had minor contributions. The two secondary OA (SOA) factors together accounted for 59%−73% of the OA mass in PM2.5. The mass distributions of particulate components in PM1 and PM2.5 varied greatly across seasons. Secondary formation played a key role in particle size growth during cold seasons. During severe hazes with high aerosol liquid water content (ALWC), the supermicron mass fraction (MF1−2.5) of secondary components reached ∼40%−50% while those for primary OA remained at ∼20%. Heterogeneous uptake, aqueous processing, and dissolution likely all contributed to the enhanced concentration of secondary components, and the former two were perhaps more important. The increase of MF1−2.5 for secondary components with increasing ALWC in spring was less than that in winter, possibly due to the shorter duration of stagnant conditions limiting secondary formation. Early autumn showed higher MF1−2.5 values than cold seasons with insignificant changes as ALWC varied, plausibly explained by intensive new particle formation hindering persistent particle growth. Our results highlight the importance of heterogeneous uptake and aqueous processing in distributing SOA in supermicron mode in polluted areas.
Semiconducting minerals (such as iron sulfides) are highly abundant in surface water, but their influences on the natural photochemical process of contaminants are still unknown. By simulating the natural water environment under solar irradiation, this work comprehensively investigated the photochemical processes of anthracene (a typical Polycyclic Aromatic Hydrocarbons) in both freshwater and seawater. The results show that the natural pyrite (NP) significantly promotes the degradation of anthracene under solar illumination via 1) NP induced photocatalytic degradation of anthracene, and 2) Fenton reaction due to the NP induced photocatalytic generation of H2O2. The material characterization and theoretical calculation reveal that the natural impurity in NP enlarges its band gap, which limits the utilization of solar spectra to shorter wavelength. The contribution of generated reactive intermediates on anthracene degradation follows the order of 1O2 > OH > O2− in freshwater and O2− > 1O2 > OH in seawater. The photochemically generated H2O2 is a vital source for OH generation (from Fenton reaction). The steady-state concentration of OH, 1O2 and O2− in freshwater were monitored as 3.0 × 10−15 M, 1.1 × 10−13 M, and 4.5 × 10−14 M, respectively. However, the OH concentration in seawater can be negligible due to the quenching effects by halides, and the 1O2 and O2− concentrations are higher than that in freshwater. An anthracene degradation kinetic model was built based on the experimentally determined reactive intermediates concentration and its second order rate constant with anthracene. Moreover, the anthracene degradation pathway was proposed based on intermediates analysis and DFT calculation, and its toxicity evolution during the photochemical process was assessed by quantitative structure-activity relationship (QSAR) based prediction. This finding suggests that the natural semiconducting minerals can affect the fate and environmental risks of contaminants in natural water.
Climate change affects cryosphere-fed rivers and alters seasonal sediment dynamics, affecting cyclical fluvial material supply and year-round water-food-energy provisions to downstream communities. Here, we demonstrate seasonal sediment-transport regime shifts from the 1960s to 2000s in four cryosphere-fed rivers characterized by glacial, nival, pluvial, and mixed regimes, respectively. Spring sees a shift toward pluvial-dominated sediment transport due to less snowmelt and more erosive rainfall. Summer is characterized by intensified glacier meltwater pulses and pluvial events that exceptionally increase sediment fluxes. Our study highlights that the increases in hydroclimatic extremes and cryosphere degradation lead to amplified variability in fluvial fluxes and higher summer sediment peaks, which can threaten downstream river infrastructure safety and ecosystems and worsen glacial/pluvial floods. We further offer a monthly-scale sediment-availability-transport model that can reproduce such regime shifts and thus help facilitate sustainable reservoir operation and river management in wider cryospheric regions under future climate and hydrological change. Intensified glacier melt and discharge pulses remarkably increase summer sediment fluxes and threaten social-ecological systems.
China is experiencing a surge in medical malpractice lawsuits. Using administrative hospital panel data, this paper investigates both short- and long-run impacts of medical malpractice lawsuits on patient medical spending and hospital operations. We find that after the occurrence of an additional malpractice lawsuit in a hospital, total medical spending per patient visit increases by 2.8% in the current year and by as much as 8.8% in the long run. This increase is mainly driven by spending on prescription drugs and diagnostic tests. In response, hospitals invest more in medical devices and procure more drugs. We find little evidence of changes in patient outcomes. Our findings show that the surge of medical malpractice lawsuits leads to defensive medicine and fuels the secular growth of medical spending in China.
Miniaturized spectrometers in the mid-infrared (MIR) are critical in developing next-generation portable electronics for advanced sensing and analysis. The bulky gratings or detector/filter arrays in conventional micro-spectrometers set a physical limitation to their miniaturization. In this work, we demonstrate a single-pixel MIR micro-spectrometer that reconstructs the sample transmission spectrum by a spectrally dispersed light source instead of spatially grated light beams. The spectrally tunable MIR light source is realized based on the thermal emissivity engineered via the metal-insulator phase transition of vanadium dioxide (VO2). We validate the performance by showing that the transmission spectrum of a magnesium fluoride (MgF2) sample can be computationally reconstructed from sensor responses at varied light source temperatures. With potentially minimum footprint due to the array-free design, our work opens the possibility where compact MIR spectrometers are integrated into portable electronic systems for versatile applications.
The era was a form of "uninterrupted, irreversible, paratactic, cumulative, endless, and directional" time-reckoning concept (Kosmin 2018: 22) widely adopted in the Roman Greek East: there were provincial eras counting from the foundation of a province, as well as more customised epochs such as the 'Freiheitsära' of Amisos (Leschhorn 1993: 463-465), and the 'Kolonieära' of Sinope (Leschhorn 1993: 150-154). Curiously, Roman Sinope began with the colonial epoch of 45 BCE, but turned to a Lucullan epoch of 70 BCE in the Severan period (Kubitschek 1908: 67-72; Grant 1946: 12, 251; Leschhorn 1993: 151-162). Leschhorn suggested reasons for the switch, including internal rivalry and 'Gräzisierung' (Leschhorn 1993: 162).
This paper explores the Graecisation hypothesis by first asking: why the Lucullan era? What was there to gain from the switch? Viewed from historical context, the Lucullan era happened to have been the time-reckoning method of Amastris, a well-developed regional hub in the second to third centuries CE (Marek 1993: 97-100; Brenier 2007), including contributions to several koina in Asia Minor. This paper suggests that Amastrian development may have influenced Sinopean institutions. Syncing time may be one way to maintain relations with a maritime hub with deep historical associations.
A second question this paper asks is how "Graecising" was the adoption of the Lucullan era. The Hellenistic amphora handles produced at Sinope stamped with the Seleucid era suggest that the use of this chronographic method predated the second century BCE (Saprykin & Fedoseev 1999: 135-143; Fedoseev 2019: 16-17). Instead of Caesarian colonists adopting a Hellenising time-reckoning, it may be that the Sinopean establishment modified (or revived) its epoch to mark both the new 'colonial' form of the Sinopean polity and the continuity of pre-colonial institutions (Magie 1950: 1267 n. 33; cf. Strab. 12.3.11 C54). In short, Sinope's changing eras may be viewed from an adaptive point of view.
Utilizing survey data from the 2010, 2014, and 2016 China family panel studies, this study examined the relationship between the social discrimination experienced at high school and college enrollment. It was found that administrative discrimination, such as unfair treatment from government cadres or arbitrary fee collection, negatively affected college enrollment, while gender discrimination encouraged high school students to pursue higher education, and college enrollment reduced the likelihood of social discrimination. Therefore, social-psychological factors should not be ignored in higher education demand studies. In particular, as high school student responses to social discrimination can affect their motivation to pursue higher education, stress and coping theory could have important theoretical value when studying the decision-making behaviors and patterns of high school student higher education aspirations.
Both developed and developing countries have seen a proliferation of information and communication technologies (ICTs) in recent years. As digital transformation has influenced almost every aspect of everyday life, including interpersonal communication, information seeking and sharing, e-commerce, and entertainment, the dichotomy between online and offline has become less distinct compared to the early years of internet development. These routine practices on the internet, nevertheless, are fundamental to understanding the impact of digital technologies on society. It is, therefore, important for social scientists to theorise and scrutinise how the internet has influenced the routine and mundane lives. To date, social scientists from multiple disciplines, including sociology, political science, communication and information science, have studied how the internet has influenced the society and economy. These include the roles of the internet in establishing and maintaining social networks, mobilising social movements, and revolutionising labour markets. However, little research has addressed the impact of the internet in the everyday lives of its users. In this chapter, I will start with reviewing theoretical frameworks from different fields that focus on the impact of the internet on daily practices, to understand the profound influence of digital technologies in everyday contexts. In particular, I will discuss how the study of everyday life information seeking (information science), domestication theory (communication science), and digital divides (sociology) contribute to the theorisation of daily uses of the internet. I will summarise empirical studies that apply these theoretical frameworks in exploring the adoption and use of ICTs in daily practices. The overview and reflection of theories and empirical studies across different social science fields will provide a comprehensive picture of the role of the internet on everyday lives, as well as point out future directions for the study of the embeddedness of the internet in people’s daily lives.
Abstract Aim Woody and herbaceous habits represent one of the most distinct contrasts among angiosperms, and the proportion of woody species in floras (i.e., “woodiness” hereafter) represents a fundamental structural element of plant diversity. Despite its core influence on ecosystem processes, spatio-temporal patterns in woodiness remain poorly understood. Here, we aim to demonstrate the global spatio-temporal patterns in angiosperm woodiness and their relationship with environmental factors. Location Global. Time period Cenozoic, 66 Ma to present. Major taxa studied Angiosperms. Methods Using newly compiled data on the growth forms and distributions of c. 300,000 angiosperm species and an angiosperm phylogeny, we mapped the current global geographical patterns in angiosperm woodiness, reconstructed ancestral states of growth forms through the angiosperm phylogeny and demonstrated the Cenozoic evolutionary dynamics of woodiness. We evaluated the relationships between woodiness and current climate and palaeoclimate. Results We found that c. 42.7% of angiosperms are woody. Woodiness decreased spatially from the equator towards high latitudes, temporally since the early Cenozoic. Temperature was the best predictor of the spatio-temporal decline in woodiness and was positively correlated with woodiness. Despite the temporal decline in woodiness, macroevolutionary herbaceous-to-woody transitions increased through time and contributed to the evolution of woody floras in temperate drylands, whereas the opposite transitions decreased through time and contributed to herbaceous floras in tropical and subtropical drylands. Main conclusions Our study improves understanding of the spatio-temporal dynamics of angiosperm woodiness. Our findings suggest that temperature is likely to be a determinant of spatio-temporal variations in woodiness, highlighting the role of temperature in maintaining the growth form composition of ecosystems. Our study also calls for attention to growth form transitions (e.g., secondary woodiness) in temperate drylands that have been neglected before.
We construct a model of debt maturity structure and show how a firm trades off between the costs of market liquidity risk and rollover risk. On one hand, the issuance of long-term debt reduces market liquidity because it increases the supply in the secondary debt market, which increases the cost the firm bears for long-term debt (i.e., the cost of market liquidity risk). On the other hand, the use of short-term debt increases the likelihood of early liquidation, which raises the cost of short-term debt for the firm (i.e., the cost of rollover risk). We show that market liquidity risk and rollover risk the firm is exposed to are connected through endogenously determined debt maturity structure. An exogenous shock (e.g., shrinkage of market depth or an increase in risk-free interest rate) that directly increases one type of liquidity risk would induce the firm to alter debt maturity structure and partially offset the impact of the shock by raising its exposure to the other type of risk (i.e., spillover effects exist). We also show that the spillover from market liquidity risk (rollover risk) to rollover risk (market liquidity risk) is more (less) pronounced during economic recessions or in the case of competitive firms.