Mercury isotopic compositions in fine particles and offshore surface seawater in a coastal area of East China: implications for Hg sources and atmospheric transformations

Isotopic compositions of Mercury (Hg) in atmospheric particles (HgPM) are probably the mixed results of emission sources and atmospheric processes. Here, we present Hg isotopic compositions in daily fine particles (PM2.5) collected from an industrial site (Chunxiao – CX) and a nearby mountain site (Daimeishan – DMS) in a coastal area of East China, and in surface seawater close to the industrial area, to reveal the influence of anthropogenic emission sources and atmospheric transformations on Hg isotopes. The PM2.5 samples displayed a significant spatial difference in δ202Hg. For the CX site, the negative δ202Hg values are similar to those of source materials, and the HgPM contents were well correlated with chemical tracers, indicating the dominant contributions of local industrial activities to HgPM2.5, whereas the observed positive δ202Hg at the DMS site was likely associated with regional emissions and extended atmospheric processes during transport. The Δ199Hg values in PM2.5 from the CX and DMS sites were comparably positive. The unity slope of Δ199Hg versus Δ201Hg over all data suggests that the odd mass independent fractionation (MIF) of HgPM2.5 was primarily induced by the photoreduction of Hg2+ in aerosols. The positive Δ200Hg values with a minor spatial difference were probably associated with the photooxidation of Hg0, which is generally enhanced in the coastal environment. Total Hg in offshore surface seawater was characterized by negative δ202Hg and near-zero Δ199Hg and Δ200Hg values, which are indistinguishable from Hg isotopes of source materials. Overall, the PM2.5 collected from industrial areas had comparable δ202Hg values but more positive Δ199Hg and Δ200Hg as compared to surface seawater. The results indicate that atmospheric transformations would induce the significant fractionation of Hg isotopes and obscure the Hg isotopic signatures of anthropogenic emissions.

Effects of Patent Policy on Outputs and Commercialization of Academic Patents in China: A Spatial Difference-in-Differences Analysis

The development of a difference-in-differences estimator is a new move in patent policy evaluation research. However, such an estimator neglects the possibility that academic patent activities follow a spatial autoregressive process with respect to the dependent variable. The objective of this study was to propose a spatial difference-in-differences estimator accounting for possible spatial spillover effects. In this study, an empirical analysis of a sample of 31 Chinese provinces from 2010 to 2019 indicates that an incentive patent policy has a positive impact on the output and commercialization of academic patents, with positive effects also spilling over into neighboring provinces. This study further found that incentive patent policies play a placebo role in academic patent activities. Provincial patent policies are merely a proxy for other variables that characterize the systemic differences between provinces that implement patent policies and those that do not. Therefore, the promotion of academic patent activities cannot be attributed to policy incentives.

The Spatial Difference of “Internet Plus Tourism” in Promoting Economic Growth

The “Internet plus Tourism” mode, which is the coordination of the internet and tourism, has become a new driving force for regional economic growth. In order to investigate the mechanism and superiority of “Internet plus Tourism” in terms of economic growth compared with the independent effects of the internet and tourism on economic growth, this paper uses the DEA model to calculate the tourism efficiency of 30 provinces in China from 2011 to 2019 and three spatial econometric models to comparatively analyze the independent effects of the internet and tourism with the synergized effect of “Internet plus Tourism” on economic growth. The results show that (1) the overall pattern of the internet is that coastal areas are ranked higher; (2) tourism efficiency presents a polarized hierarchical structure; (3) The effect of “Internet plus Tourism” on economic growth is significantly positive and is significantly greater than the independent effects of the internet and tourism on economic growth; (4) the internet, tourism, and “Internet plus Tourism” have different effects on economic growth in different regions. Therefore, the paper suggests that China should accelerate the integration of “Internet plus Tourism” and realize sustainable economic development.

Characteristics of Soil Aggregates and Its Organic Carbon in Daxing'anling Forest Region

The distribution and spatial variability of soil aggregates and their organic carbon and their responses to environmental factors in Daxing'anling forest region were studied by field investigation and laboratory analysis. In Daxing'anling forest region, 75 sampling points were set up based on kilometer grid, and the sample circle with radius of 17.85m was set at each sampling point. In each circle, three samples of 0-20 cm topsoil were taken to determine soil chemical indexes, soil aggregates and their organic carbon content. The results showed that: (1) the soil aggregate content followed the order as (0.25~2 mm aggregate) > (<0.053 mm aggregate) > (0.053~0.25 mm aggregate). The spatial autocorrelation of each fraction of aggregate were moderate, and they were affected by the structural factors such as climate, vegetation, soil and random factors such as human activities. The content of 0.25~2 mm and <0.053 mm aggregates decreased gradually from north to south, while the content of 0.053~0.25 mm aggregates was opposite to them. (2) The organic carbon content of soil aggregates was mainly concentrated in the 0.25~2 mm large aggregates (19.84 g/kg) with the contribution rate 50.39%; the organic carbon contents of each fraction of aggregate showed high spatial autocorrelation which was mainly affected by structural factors; the spatial difference of soil aggregate content in each particle size was not significant, and the distribution was patchy. There was no significant spatial difference in the organic carbon contents of soil aggregate in different fractions with patch distribution characteristics. (3) Temperature had no significant effect on the formation and stability of soil aggregates, and precipitation is beneficial to the formation of micro-aggregates <0.053 mm; soil organic carbon was conducive to the cementation of small-sized aggregates into large aggregates, which had a positive effect on the stability of soil aggregates. There was a significant positive correlation between SOC and organic carbon of soil aggregates in different fractions, and the correlation degree was gradually weakened with the decrease of particle size; the contents of soil nitrogen, phosphorus, potassium and other nutrients could promote the organic carbon accumulation in soil aggregates. The results can provide the basis for the soil rational use and the carbon fixation capacity improvement of forest in Daxing'anling forest region.

Online-to-offline advertisements as field experiments

Online advertisements have become one of today’s most widely used tools for enhancing businesses partly because of their compatibility with A/B testing. A/B testing allows sellers to find effective advertisement strategie,s such as ad creatives or segmentations. Even though several studies propose a technique to maximize the effect of an advertisement, there is insufficient comprehension of the customers’ offline shopping behavior invited by the online advertisements. Herein, we study the difference in offline behavior between customers who received online advertisements and regular customers (i.e., the customers visits the target shop voluntary), and the duration of this difference. We analyze approximately three thousand users’ offline behavior with their 23.5 million location records through 31 A/B testings. We first demonstrate the externality that customers with advertisements traverse larger areas than those without advertisements, and this spatial difference lasts several days after their shopping day. We then find a long-run effect of this externality of advertising that a certain portion of the customers invited to the offline shops revisit these shops. Finally, based on this revisit effect findings, we utilize a causal machine learning model to propose a marketing strategy to maximize the revisit ratio. Our results suggest that advertisements draw customers who have different behavior traits from regular customers. This study demonstrates that a simple analysis may underrate the effects of advertisements on businesses, and an analysis considering externality can attract potentially valuable customers.

Nanoscale organization of Nicastrin, the substrate receptor of the γ-secretase complex, as independent molecular domains

Alterations in the canonical processing of Amyloid Precursor Protein generate proteoforms that contribute to the onset of Alzheimer’s Disease. Modified composition of γ-secretase or mutations in its subunits has been directly linked to altered generation of Amyloid beta. Despite biochemical evidence about the role of γ-secretase in the generation of APP, the molecular origin of how spatial heterogeneity in the generation of proteoforms arises is not well understood. Here, we evaluated the localization of Nicastrin, a γ-secretase subunit, at nanometer sized functional zones of the synapse. With the help of super resolution microscopy, we confirm that Nicastrin is organized into nanodomains of high molecular density within an excitatory synapse. A similar nanoorganization was also observed for APP and the catalytic subunit of γ-secretase, Presenilin 1, that were discretely associated with Nicastrin nanodomains. Though Nicastrin is a functional subunit of γ-secretase, the Nicastrin and Presenilin1 nanodomains were either colocalized or localized independent of each other. The Nicastrin and Presenilin domains highlight a potential independent regulation of these molecules different from their canonical secretase function. The collisions between secretases and substrate molecules decide the probability and rate of product formation for transmembrane proteolysis. Our observations of secretase nanodomains indicate a spatial difference in the confinement of substrate and secretases, affecting the local probability of product formation by increasing their molecular availability, resulting in differential generation of proteoforms even within single synapses.