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.
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.
Field observations of reactive volatile organic compounds (VOCs) were carried out in Kunming, the largest city on the Yunnan-Guizhou Plateau. Proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) was used to conduct a 40-day online observation. VOCs were characterized, including concentrations, diurnal variations, ozone generation potential, and source apportionment. The results show 18 main observed active VOCs (acetaldehyde, 2-acrolein, acetone, methyl ethyl ketone (MEK), methyl vinyl ketone (MVK), methacrolein (MACR), methyl isobutyl ketone (MIK), 2-pentanone, ethyl acetate, isoprene, α-pinene, benzene, toluene, styrene, C8 aromatic hydrocarbons, C9 aromatic hydrocarbons, 1,3-dichlorobenzene, naphthalene and acetonitrile) with a total concentration of (10.97 ± 5.21) ppb. Eight OVOCs have a total concentration of (7.49 ± 3.10) ppb; two biogenic VOCs (BVOCs) have a total concentration of (1.32 ± 0.79) ppb, and six aromatic hydrocarbons have a total concentration of (1.50 ± 1.14) ppb. The ozone formation potential of isoprene, acetaldehyde and 2-acrolein make up the top three species. The main sources of three OVOC species (acetaldehyde, acetone, and MEK) have local biological sources and primary anthropogenic sources, indicating that the pollution in this area is significantly affected by regional transport. This study can improve our scientific understanding of the composition and sources of VOCs on the Yunnan-Guizhou Plateau and fundamental ozone control in the region.
Abstract Geological CO2 storage is an emerging topic in energy and environmental community, which is, as a commonly accepted sense, considered as the most promising and powerful approach to mitigate the global carbon emissions during the transition to net-zero. Of the geological media which initially considered cover the saline aquifers, oil and gas reservoirs, coal beds, and potentially basalts, up to now only the first two choices have been proven to be the most capable storage sites and successfully implemented at pilot/commercial scales. Here, two tandem papers propose novel strategies for the first time, by synthesizing and utilizing new high-dryness CO2 foam, to enhance geological CO2 storage capacity in saline aquifer and oil and gas reservoirs. In this paper, a new high-dryness CO2 foam is synthesized and injected into the saline aquifers to explore the storage capacity enhancement, with the unique foam-induced advantages of sweep area expansion and storage efficiency improvement. Such a new idea is specifically evaluated and validated through a series of static analytical and dynamic performance experiments. With the optimum surfactant concentration of 0.5 wt%, the foaming volume and quality are determined to be 521 mL and 80.81%, respectively, which also shows excellent salt tolerance with 45,000 ppm Na+, 25,000 ppm Ca2+, and 25,000 ppm Mg2+. Moreover, the water consumption for CO2 storage decreases from 464.31 g/mol at 25% foam quality to 67.38 g/mol at 85% foam quality by using the new CO2 foam. Overall, the newly synthesized CO2 foam could effectively enhance geological CO2 storage capacity and concurrently diminish water consumption, therefore realizing the win-win environment and economic benefits.