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This study investigates long-term trends of criteria air pollutants, including NO2, CO, SO2, O3 and PM2.5, and (NO2+O3) measured in ten Canadian cities during the last two to three decades and associated driving forces in terms of emission reductions, perturbations from varying weather conditions and large-scale wildfires, and changes in O3 sources and sinks. Two machine-learning methods, including random forest algorithm and boosted regression trees, were used to extract deweathered mixing ratios (or mass concentrations) of the pollutants. The Mann-Kendall analysis of the deweathered and original annual average concentrations of the pollutants showed that, on the time scale of 20 years or longer, the perturbation from varying weather conditions exerted a very minor influence on the decadal trends of original annual averages (within 2%) in ~70% of the cases, and a moderate influence up to 16% of the original trends in the other 30% cases. NO2, CO and SO2 showed decreasing trends in the last two to three decades in all the cities except CO in Montreal. O3 showed increasing trends in all the cities, except Halifax, mainly due to weakened titration reaction between O3 and NO. (NO2+O3), however, showed decreasing trends in all the cities, except Victoria, because the increase in O3 is much less than the decrease in NO2. In three of the five eastern Canadian cities, emission reductions dominated the decreasing trends in PM2.5, but no significant trends in PM2.5 were observed in the other two cites. In five western Canadian cities, increasing or no significant trends in PM2.5 were observed, likely due to unpredictable large-scale wildfires overwhelming or balancing the impacts of emission reductions on PM2.5. In addition, despite improving air quality during the last two decades in most cities, air quality health index of above 10 (representing very high-risk condition) still occasionally occurred after 2010 in western Canadian cities because of the increased large-scale wildfires. [ABSTRACT FROM AUTHOR]

Organic aerosols from marine sources over the western Pacific Ocean of East Asia were investigated by using an online-coupled regional chemistry-climate model RIEMS-Chem for the entire year 2014. Model evaluation against a wide variety of observations from research cruises and in-situ measurements demonstrated a good skill of the model in simulating temporal variation and spatial distribution of particulate matter with aerodynamic diameter less than 2.5 μm and 10 μm (PM2.5 and PM10), black carbon (BC), organic carbon (OC), sodium, and aerosol optical depth (AOD) in the marine atmosphere. The inclusion of marine organic aerosols apparently improved model performance on OC aerosol concentration. The regional and annual mean near surface marine organic aerosol (MOA) concentration was estimated to be 0.27 μg m-3, with the maximum in spring and the minimum in winter and contributed 26% of the total organic aerosol concentration on average over the western Pacific. Marine primary organic aerosol (MPOA) accounted for the majority of marine organic aerosol (MOA) mass and exhibited the maximum in autumn and the minimum in summer, whereas marine secondary organic aerosol (MSOA) was approximately 1~2 orders of magnitude lower than MPOA, having a distinct summer maximum and a winter minimum. MOA induced a direct radiative effect (DREMOA) of -0.27 W m-2, and an indirect radiative effect (IREMOA) of -0.66 W m-2 at TOA (IREMOA) in terms of annual and oceanic average over the western Pacific, with the highest seasonal mean IREMOA up to -0.94 W m-2 in spring. IREMOA was stronger than but in a similar magnitude to the IRE due to sea salt aerosol on average, and it was approximately 9% of the IRE due anthropogenic aerosols in terms of annual mean over the western Pacific, and this ratio increased to 19% in the northern parts of the western Pacific in autumn. This study reveals an important role of MOA in perturbing cloud properties and shortwave radiation fluxes in the western Pacific of East Asia. [ABSTRACT FROM AUTHOR]

PM2.5 pollution is a major air quality issue deteriorating human health, and numerous studies focus on PM2.5 pollution in major regions such as North China Plain (NCP) and Yangtze River Delta (YRD). However, the characteristics of PM2.5 concentrations and the associated formation mechanism in the transport corridor (referred to as SWLY) between NCP and YRD are largely ignored. Based on observational data, we find the number of PM2.5 pollution events in SWLY is comparable to that in NCP, far exceeding those in YRD, indicative of the severity of air pollution over this area. Utilizing a regional climate and air quality model, we isolate the effect of seesaw transport events, e.g., transport between NCP and YRD, as well as the atmospheric stagnation on the accumulation of PM2.5 over SWLY. Specifically, seesaw events and stagnation, comparable to each other, collectively account for an average of 67 % pollution days with PM2.5 exceeding 75 µg/m³, and this fraction (85 %) is even larger for severe haze events with PM2.5 exceeding 150 µg/m³. Furthermore, the connection between seesaw transport and large-scale circulation is examined. The trans-regional transport of pollutants from NCP to YRD (YRD to NCP) is likely stimulated by positive (negative) to negative (positive) geopotential height anomaly at 500 hPa located in northern China. The health effect due to short-term PM2.5 exposure induced by the trans-regional transport and stagnation is investigated, yielding a total of 8,634 (95 % CI: 6,023–11,223) and 9,496 (95 % CI: 6,552–12,413) premature deaths respectively in SWLY during winter 2014–2019, as high as 9 % of the total premature deaths in China although the area coverage of SWLY is within 1 %. While atmospheric stagnation is in general projected to occur more frequently under a warming climate, this study indicates the importance of regional emission control to alleviate PM2.5 pollution from seesaw transport and stagnation. [ABSTRACT FROM AUTHOR]

In this study, we utilized a 20-bin WRF-Chem (Weather Research and Forecast coupled with Chemistry regional model) to investigate the contributions of chemical drivers to the growth of newly formed particles, as well as to simulate the three-dimensional dynamics of new particle formation (NPF) events over the North China Plain during a summer campaign in 2019, which was reported in the accompanying paper. The model demonstrated good performance in replicating the occurrence of NPF, the growth pattern of newly formed particles, and the number concentration of particles in the size range of 10–40 nm in five events between June 29 and July 6. This period was characterized by a high frequency of NPF occurrence (>60 %). During this time, the model was also able to accurately reproduce the levels of organics in PM1.0 relative to observations, and to reasonably replicate the levels of SO4 2- and NH4 + in PM1.0, as well as PM2.5 mass concentrations. Therefore, we further analyzed three NPF events with distinct particle growth characteristics: Case 1, featuring observable growth of newly formed particles to cloud condensation nuclei (CCN) size on July 1–2; Case 2, characterized by continuous growth of new particles for several hours without any net contribution to CCN on July 3; and Case 3, where no detectable continuous growth of newly formed particles was observed on July 6. In these instances, the model tended to overpredict the condensation of H2SO4 vapor during daytime and the formation of NH4NO3 during nighttime, resulting in an overestimation of the hygroscopicity parameter of nanometer particles. Nevertheless, the model was able to reasonably reproduce the CCN (cloud condensation nuclei) at a super saturation (SS) of 0.4 % on days with NPF, compared to the observations. This was because the overestimation effect caused by inorganics was offset by the model's underestimation of CCN originating from submicron-sized particles. Additionally, three-dimensional simulations of NPF events have demonstrated some key findings. Firstly, NPF consistently initiates at the upper fraction of the planetary boundary layer (PBL) before expanding. Secondly, during daytime growth of newly formed particles in the PBL, organics play a dominant role, whereas the primary chemical drivers shift to inorganic species in the free troposphere. However, to confirm these findings, vertical observations are required. [ABSTRACT FROM AUTHOR]

New particle formation (NPF) and subsequent particle growth are important sources of condensation nuclei (CN) and cloud condensation nuclei (CCN). While a number of observations have shown positive contributions of NPF to CCN at low supersaturation, negative NPF contributions were often simulated. Using the observations in a typical coastal city of Qingdao, we thoroughly evaluate the simulated number concentrations of CN and CCN using a NPF-explicit parameterization embedded in WRF-Chem model. In terms of CN, the initial simulation shows large biases of particle number concentrations at 10-40 nm (CN10-40) and 40-100 nm (CN40-100). By adjusting the process of gas-particle partitioning, including mass accommodation coefficient of sulfuric acid, the phase changes of primary organic aerosol emissions and the condensational amount of nitric acid, the concomitant improvement of the particle growth process yields a substantial reduction of overestimates of CN10-40 and CN40-100. Regarding CCN, SOA formed from the oxidation of semi-volatile and intermediate volatility organic vapors (SI-SOA) yield is an important contributor. In the original WRF-Chem model with 20 size bins setting, the yield of SI-SOA is too high without considering the differences in oxidation rates of the precursors. Lowering the SI-SOA yield results in much improved simulations of the observed CCN concentrations. On the basis of the bias-corrected model, we find substantial positive contributions of NPF to CCN at low supersaturation (~0.2%) in Qingdao and over the broad areas of China, primarily due to the competing effects of increasing particle hygroscopicity surpassing that of particle size decrease. This study highlights the potentially much larger NPF contributions to CCN on a regional and even global basis. [ABSTRACT FROM AUTHOR]

This study employed multiple techniques to investigate the contribution of grown new particles to the number concentration of cloud condensation nuclei (CCN) at various supersaturation (SS) levels at a rural mountain site in North China Plain from 29 June to 14 July 2019. On eight new particle formation (NPF) days, the total particle number concentrations (Ncn) were 8.4±6.1 x10³ cm-3, which were substantially higher compared to 4.7±2.6 x10³ cm-3 on non-NPF days. However, the Nccn at 0.2 %SS and 0.4 %SS on the NPF days were significantly lower than those observed on non-NPF days (P<0.05). This was due to the lower cloud activation efficiency of pre-existing particles resulting from organic vapor condensation and smaller number concentrations of pre-existing particles on NPF days. A case-by-case examination showed that the grown new particles only yielded a detectable contribution to Nccn at 0.4 % SS and 1.0 % SS during the NPF event on 1 July 2019, accounting for 12±11 % and 23±12 % of Nccn, respectively. The increased Nccn during two other NPF events and at 0.2 % SS on 1 July 2019 were detectable, but determined mainly by varying pre-existing particles rather than grown new particles. In addition, the hygroscopicity parameter values, concentrations of inorganic and organic particulate components, and surface chemical composition of different sized particles were analyzed in terms of chemical drivers to grow new particles. The results showed that the grown new particles via organic vapor condensation generally had no detectable contribution to Nccn, but incidentally did. However, this conclusion was drawn from a small size of observational data, leaving more observations, particularly for long-term observations and the growth of pre-existing particles to the CCN required size, needed for further investigation. [ABSTRACT FROM AUTHOR]

In this study, three methods including the random forest (RF) algorithm, boosted regression trees (BRTs) and the improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) were adopted for investigating emission-driven interannual variations in concentrations of air pollutants including PM2.5, PM10, O3, NO2, CO, SO2 and (NO2+O3) monitored in six cities in south China from May 2014 to April 2021. The first two methods were used to calculate the deweathered hourly concentrations, and the third one was used to calculate decomposed hourly residuals. To constrain the uncertainties in the calculated deweathered or decomposed hourly values, a self-developed method was applied to calculate the range of the deweathered percentage changes (DePCs) of air pollutant concentrations in annual scale. Emission-driven trends and emission-driven percentage changes (PCs) during the whole seven-year period were generated with the four methods being applied to analyzing the data. The consistency in the trends between the RF-deweathered and BRTs-deweathered concentrations and the ICEEMDAN-decomposed residuals of an air pollutant in a city reaches approximately 70% of all the studied cases, but that in the PCs reaches only approximately 30% of all the cases. The remaining cases with inconsistent trends and/or PCs indicated large uncertainties produced by one or more of the three methods. The calculated PCs from the deweathered concentrations and decomposed residuals were thus combined with the corresponding range of DePCs calculated from the self-developed method to gain the robust range of DePCs where applicable. Building on the robust ranges, the mitigation effects were discussed. [ABSTRACT FROM AUTHOR]

Atmospheric new particle formation (NPF) events have attracted increasing attention for their contribution to the global aerosol number budget, and therefore their effects on climate, air quality, and human health. NPF events are regarded as a regional phenomenon, occurring over a large area. However, the spatial variation of NPF intensity has not been investigated in detail by incorporating both urban and regional measurements. Urban environments have more heterogeneous and freshly emitted NPF precursors as compared to environments with less anthropogenic activity. Here, we provide a comparison of NPF event characteristics - NPF event frequency, particle formation rate, and growth rate - by comparing an urban Beijing site and a background mountain site separated by ~80 km from June 14 to July 14, 2019 as well as give insights into the connection between both locations. During the measurement period, 12 and 13 NPF events were observed at the urban and background mountain sites, respectively, with 9 NPF events observed on the same day at both sites. Although the median condensation sink during the first two hours of the common NPF events was around 0.01 s-1 at both sites, there were notable differences in particle formation rates between the two locations (median of 5.42 cm-3 s-1 at the urban site and 1.13 cm-3 s-1 at the mountain site during the first two hours of common NPF events). Yet, the particle growth rates in the 7-15 nm range for common NPF events were comparable (median of 7.6 nm.h-1 at the urban site and 6.5 nm.h-1 at the mountain site as median values). To understand whether the observed events were connected, we compared air mass trajectories as well as meteorological conditions at both stations. Favorable conditions for the occurrence of regional NPF events were largely affected by air mass transport. Overall, our results demonstrate a clear inhomogeneity of regional NPF within a distance of ~100 km, which should be considered in regional-scale aerosol models when estimating the budget of aerosol load and cloud condensation nuclei. [ABSTRACT FROM AUTHOR]

Arsenic is a toxic pollutant commonly found in the environment. Most of the previous studies on arsenic pollution have primarily focused on arsenic contamination in groundwater. In this study, we examine the impact on human health from atmospheric arsenic on the global scale. We first develop an improved global atmospheric arsenic emission inventory and connect it to a global model (Goddard Earth Observing System [GEOS]-Chem). Model evaluation using observational data from a variety of sources shows the model successfully reproduces the spatial distribution of atmospheric arsenic around the world. We found that for 2005, the highest airborne arsenic concentrations were found over Chile and eastern China, with mean values of 8.34 and 5.63 ng/m², respectively. By 2015, the average atmospheric arsenic concentration in India (4.57 ng/m²) surpassed that in eastern China (4.38 ng/m²) due to the fast increase in coal burning in India. Our calculation shows that China has the largest population affected by cancer risk due to atmospheric arsenic inhalation in 2005, which is again surpassed by India in 2015. Based on potential exceedance of health-based limits, we find that the combined effect by including both atmospheric and groundwater arsenic may significantly enhance the risks, due to carcinogenic and noncarcinogenic effects. Therefore, this study clearly implies the necessity in accounting for both atmospheric and groundwater arsenic in future management. [ABSTRACT FROM AUTHOR]

Because anthropogenic sulfur dioxide (SO2) emissions have decreased considerably in the last decade, PM2.5 pollution in China has been alleviated to some extent. However, the effects of reduced SO2 on the particle number concentrations and subsequent contributions of grown new particles to the cloud condensation nuclei (CCN) populations, particularly at high altitude with low aerosol number loadings, are poorly understood. In this study, we evaluated the campaign-based measurements made at the summit of Mt. Tai (1534 m a.s.l.) from 2007 to 2018. With the decrease in the SO2 mixing ratios from 15 ± 13 ppb in 2007 to 1.6 ± 1.6 ppb in 2018, the formation rate of new particles (FR) and the net maximum increase in the nucleation-mode particle number concentration (NMINP) increased by 2-3 fold in 2018 against those in 2007. In contrast, the occurrence frequency of new particle formation (NPF) events in which the maximum geometric median diameter of grown new particles (Dpgmax) was >50 nm decreased considerably from 43%-78% of the NPF events before 2015 to <12% in 2017-2018. Assuming >50 nm as a CCN threshold size at high supersaturations, the observed net CCN production decreased from 3703 cm-3 (on average) before 2015 to 1026 cm-3 (on average) in 2017-2018. We argue that the increase in the FR and NMINP is mainly determined by the availability of organic precursors that participate in nucleation and initial growth, whereas the decrease in the growth probability is caused by the reduced emissions of anthropogenic precursors. However, large uncertainties still exist because of a lack of data on the chemical composition of these smaller particles. [ABSTRACT FROM AUTHOR]

The growth of newly formed particles with diameters from ~ 10 nm to a larger size was investigated in Beijing's urban atmosphere on 10-23 December 2011, 12-27 April 2012 and through June-August 2014. The maximum geometric median diameter (Dpgmax) of newly formed particles in 11/27 new particle formation (NPF) events through June-August exceeded 75 nm, and the grown new particles may contribute to the population of cloud condensation nuclei. In contrast, no apparent growth in new particles with Dpgmax < 20 nm was observed in all of the events occurring in December, in approximately half of the NPF events occurring in April and only 2/27 of the NPF events occurring in June-August. New particles observed in the latter NPF events were too small to be activated as cloud condensation nuclei. Apparent new particle growth with Dpgmax < 50 nm was observed in the remaining NPF events. The 11/27 NPF events with Dpgmax exceeded 75 nm were thereby analyzed in-depth. They are clearly three particle growth pattern classifications: one-stage growth, which is characterized by a continuous increase in Dpgmax > 80 nm (4/11 NPF events), and two-stage growth-A and growth-B, which are characterized by either no apparent growth (two-stage growth-A) or a shrinkage of particles (two-stage growth-B) in the middle 2-4 hours of the growth period (7/11 NPF events). Combining the observations of gaseous pollutants and the measured (or modeled) concentrations of particulate chemical species, the three growth patterns were discussed in terms of the spatial heterogeneity of NPF, the formation of secondary aerosols and the evaporation of semi-volatile particulates. Secondary organic species and NH4NO3 were argued to be two major contributors to the growth in new particles, but NH4NO3 likely contributed to growth only in the late afternoon and/or at nighttime. [ABSTRACT FROM AUTHOR]

Water soluble inorganic ions such as ammonium, nitrate, and sulfate are major components of fine aerosols in the atmosphere and are widely used in the estimation of aerosol acidity. However, different experimental practices and instrumentation may lead to uncertainties in ion concentrations. Here, an inter-comparison experiment was conducted in 10 different laboratories (labs) to investigate the consistency of inorganic ion concentrations and resultant aerosol acidity estimates using the same set of aerosol filter samples. The results mostly exhibited good agreement for major ions Cl-, SO42-, NO3-, NH4+ and K+. However, F-, Mg2+ and Ca2+ were observed with more variations across the different labs. The Aerosol Chemical Speciation Monitor (ACSM) data of non-refractory SO42-, NO3-, NH4+ generally correlated very well with the filter analysis based data in our study, but the absolute concentrations differ by up to 42 %. Cl- from the two methods are correlated but the concentration differ by more than 3 times. The analyses of certified reference materials (CRMs) generally showed good recovery of all ions in all the labs, the majority of which ranged between 90 % and 110 %. Better agreements were found for Cl-, SO42-, NO3-, NH4+ and K+ across the labs after their concentrations were corrected with CRM recoveries; the coefficient of variation (CV) of Cl-, SO42-, NO3-, NH4+ and K+ decreased 1.7 %, 3.4 %, 3.4 %, 1.2 % and 2.6 %, respectively, after CRM correction. We found that the ratio of anion to cation equivalent concentrations (AE/CE) is not a good indicator for aerosol acidity estimates, as the results in different labs did not agree well with each other. Ion balance (anions - cations) calculated from SO42-, NO3- and NH4+ gave more consistent results, because of their relatively large concentrations and good agreement among different labs. In situ aerosol pH calculated from the ISORROPIA-II thermodynamic equilibrium model with measured ion and ammonia concentrations showed a similar trend and good agreement across the 10 labs. Our results indicate that although there are important uncertainties in aerosol ion concentration measurements, the estimated aerosol pH from the ISORROPIA-II model is more consistent. [ABSTRACT FROM AUTHOR]

In this study, a cruise campaign was conducted over China marginal seas to measure concentrations of condensation nuclei (Ncn), cloud condensation nuclei (Nccn) and other pollutants during DOY 110 to DOY 135 of 2018. With exhaustedly excluded self-ship emission signals, the mean values of Nccn during the cruise campaign slightly increased from 3.2 ± 1.1 x 10³ cm-3 (mean ± standard) at supersaturation (SS) of 0.2 % to 3.9 ± 1.4 x 10³ cm-3 at SS of 1.0 %, and the mean value for Ncn was 8.1 ± 4.4 x 10³ cm-3. Data analysis showed that marine traffic emissions apparently yielded a large contribution to the increase of Ncn in daytime, especially in marine atmospheres over their heavily travelled sea zones; however, the fresh sources had no clear contribution to the increase of Nccn. This finding was supported by the quantitative relations between Ncn and Nccn at SS = 0.2-1.0 % against mixing ratios of SO2 in self-ship emission plumes, i.e., 1 ppb increase in SO2 corresponds to 1.4 x 104 cm-3 increase in Ncn, but only 30-170 cm-3 increase in Nccn possibly because of abundant organics in the aerosols. The smooth growth of marine traffic derived particles can be observed, reflecting aerosol aging. The estimated hygroscopicity parameter (κ) values were generally as high as 0.46-0.55 under the dominant onshore winds, suggesting inorganic ammonium aerosols likely acting as the major contributor to Nccn through aerosol aging processes largely decomposed organics. Moreover, the influences of the transported new particles from the continent on Ncn and Nccn in the marine atmosphere were also investigated. [ABSTRACT FROM AUTHOR]

We investigated the geographic distributions of organic tracers in total suspended particles over marginal seas of China, including the Yellow and Bohai seas (YBS) and the South China Sea (SCS), and the northwest Pacific Ocean (NWPO) in spring, when Asian outflows strongly affect downwind marine atmospheres. The comparison of levoglucosan observed in this study with values from the literature implied that the contribution from biomass burning emissions to marine aerosols over the NWPO may have increased largely over the last decades. The increase led to the mean value of levoglucosan (8.2 ± 14 ng m-3) observed over the NWPO closer to that over the SCS and almost half of that over the YBS. Small geographic differences in monoterpene-derived and sesquiterpene-derived secondary organic tracer concentrations were obtained among the three atmospheres, although the causes may differ. By contrast, a large difference in isoprene-derived secondary organic tracer concentrations was observed among the three atmospheres, with the sum of tracer concentrations over the SCS (45 ± 54 ng m-3) several times and approximately one order of magnitude greater than that over the YBS (15 ± 16 ng m-3) and the NWPO (2.3 ± 1.6 ng m-3), respectively. The geographic distribution of aromatic-derived secondary organic tracers was similar to that of isoprene-derived secondary organic tracers, with a slightly narrower difference, i.e., 1.8 ± 1.7 ng m-3, 1.1 ± 1.4 ng m-3 and 0.3 ± 0.5 ng m-3 over the SCS, the YBS and the NWPO, respectively. We discuss the causes of the distinctive geographic distributions of these tracers and present the tracer-based estimation of organic carbon. [ABSTRACT FROM AUTHOR]

Objective: Glioblastoma (GBM) is the most common primary malignant brain tumor regulated by numerous genes, with poor survival outcomes and unsatisfactory response to therapy. Therefore, a robust, multi-gene signature-derived model is required to predict the prognosis and treatment response in GBM. Methods: Gene expression data of GBM from TCGA and GEO datasets were used to identify differentially expressed genes (DEGs) through DESeq2 or LIMMA methods. The DEGs were then overlapped and used for survival analysis by univariate and multivariate COX regression. Based on the gene signature of multiple survival-associated DEGs, a risk score model was established, and its prognostic and predictive role was estimated through Kaplan-Meier analysis and log-rank test. Gene set enrichment analysis (GSEA) was conducted to explore high-risk score-associated pathways. Western blot was used for protein detection. Results: Four survival-associated DEGs of GBM were identified: OSMR, HOXC10, SCARA3, and SLC39A10. The four-gene signature-derived risk score was higher in GBM than in normal brain tissues. GBM patients with a high-risk score had poor survival outcomes. The high-risk group treated with temozolomide chemotherapy or radiotherapy survived for a shorter duration than the low-risk group. GSEA showed that the high-risk score was enriched with pathways such as vasculature development and cell adhesion. Western blot confirmed that the proteins of these four genes were differentially expressed in GBM cells. Conclusions: The four-gene signature-derived risk score functions well in predicting the prognosis and treatment response in GBM and will be useful for guiding therapeutic strategies for GBM patients. [ABSTRACT FROM AUTHOR]

Long-term trends of wet deposition of inorganic ions are affected by multiple factors, among which emission changes and climate conditions are dominant ones. To assess the effectiveness of emission reductions on the wet deposition of pollutants of interest, contributions from these factors to the long-term trends of wet deposition must be isolated. For this purpose, a two-step approach for preprocessing wet deposition data is presented herein. This new approach aims to reduce the impact of climate anomalies on the trend analysis so that the impact of emission reductions on wet deposition can be revealed. This approach is applied to a two-decade wet deposition dataset of sulfate (SO42−), nitrate (NO3−) and ammonium (NH4+) at rural Canadian sites. Analysis results show that the approach allows for robustly identifying inflection points on decreasing trends in the wet deposition fluxes of SO42− and NO3− in northern Ontario and Québec. The inflection points match well with the three-phase mitigation of SO2 emissions and two-phase mitigation of NOx emissions in Ontario. Improved correlations between the wet deposition of ions and their precursors' emissions were obtained after reducing the impact from climate anomalies. Furthermore, decadal climate anomalies were identified as dominating the decreasing trends in the wet deposition fluxes of SO42− and NO3− at a western coastal site. Long-term variations in NH4+ wet deposition showed no clear trends due to the compensating effects between NH3 emissions, climate anomalies, and chemistry associated with the emission changes of sulfur and nitrogen. [ABSTRACT FROM AUTHOR]

In the summer of 2017, heavy ozone pollution swamped most of the North China Plain (NCP), with the maximum regional average of daily maximum 8-h ozone concentration (MDA8) reaching almost 120ppbv. In light of the continuing reduction of anthropogenic emissions in China, the underlying mechanisms for the occurrences of these regional extreme ozone episodes are elucidated from two perspectives: meteorology and biogenic emissions. The significant positive correlation between MDA8 and temperature, which is amplified during heat waves concomitant with stagnant air and no precipitation, supports the crucial role of meteorology in driving high ozone concentrations. We also find that biogenic emissions are enhanced due to factors previously not considered. During the heavy ozone pollution episodes in June 2017, biogenic emissions driven by high vapor pressure deficit (VPD), land cover change and urban landscape yield an extra mean MDA8 ozone of 3.08, 2.79 and 4.74ppbv, respectively over the NCP, which together contribute as much to MDA8 ozone as biogenic emissions simulated using the land cover of 2003 and ignoring VPD and urban landscape. In Beijing, the biogenic emission increase due to urban landscape has a comparable effect on MDA8 ozone to the combined effect of high VPD and land cover change between 2003 and 2016. This study highlights the vital contributions of heat waves, land cover change and urbanization to the occurrence of extreme ozone episode, with significant implications for ozone pollution control in a future when heat wave frequency and intensity are projected to increase under global warming. [ABSTRACT FROM AUTHOR]

The updated concentrations of atmospheric particles (Ncn) and the concentrations of cloud condensation nuclei (Nccn) over the northwestern Pacific Ocean (NWPO) were important to accurately evaluate the influence of aerosol outflow from the Asian continent on the climate by considering rapid changes in emissions of air pollutants therein. However, field observations were scarce in the last two decades. We conducted a cruise campaign over the NWPO to simultaneously measure Ncn, Nccn and the size distribution of aerosol particles from DOY 81 to DOY 108 of 2014. The mean values of Nccn at supersaturation (SS) of 0.2% and 0.4% were 0.68±0.38×103cm-3 and 1.1±0.67×103cm-3, respectively, with an average for Ncn of 2.8±1.0×103cm-3 during the cruise over the NWPO, which were all approximately one order of magnitude larger than spring observations from two decades ago in the atmosphere of remote marine areas. The higher values, against the marine natural background reported in the literature, implied an overwhelming contribution from continental inputs. The calculated CCN activity ratios were 0.30±0.11 and 0.46±0.19 at SS of 0.2% and 0.4%, respectively, which were almost the same as those of upwind semi-urban sites. High Nccn and CCN activities were observed from DOY 98 to 102, when the oceanic zone received even stronger continental inputs. During the whole cruise period with the exclusion of biomass burning and dust aerosols, a good correlation between Nccn at 0.4% SS and the number concentrations of >60nm particles (N>60nm), with the slope of 0.98 and R2=0.94, was obtained, and the corresponding effective hygroscopicity parameter (k) was estimated as 0.40. The bimodal size distribution pattern of the particle number concentration was generally observed during the entire campaign when the N>90nm varied largely. However, the N<30nm, accounting for approximately 1/3 of the total number concentration, varied narrowly, and two NPF events associated with vertical transport were observed, implying a pool of nucleation mode atmospheric particles aloft. Biomass burning (BB) and dust events were observed over the NWPO, but the contributions of BB and dust aerosols to Ncn and Nccn were minor (i.e., 10% or less) on the monthly time scale. [ABSTRACT FROM AUTHOR]

A multi-model ensemble of Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) simulations are used to study the atmospheric oxidized nitrogen (NOy) deposition over East Asia under climate and emission changes projected for the future. Both dry and wet NOy deposition shows significant decreases in the 2100s under RCP 4.5 and RCP 8.5, primarily due to large anthropogenic emission reduction over both land and sea. However, in the near future of the 2030s, both dry and wet NOy deposition increases significantly due to continued increase in emissions. The individual effect of climate or emission changes on dry and wet NOy deposition is also investigated. The impact of climate change on dry NOy deposition is relatively minor, but the effect on wet deposition, primarily caused by changes in precipitation, is much higher. For example, over the East China Sea, wet NOy deposition increases significantly in summer due to climate change by the end of this century under RCP 8.5, which may subsequently enhance marine primary production. Over the coastal seas of China, as the transport of NOy from land becomes weaker due to the decrease of anthropogenic emissions, the effect of ship emission and lightning emission becomes more important. On average, seasonal mean total NOy deposition is projected to be enhanced by 24-48 % and 3 %-37 % over Yellow Sea and East China Sea, respectively, by the end of this century. Therefore, continued control of both anthropogenic emission over land and ship emissions may reduce NOy deposition to the Chinese coastal seas. [ABSTRACT FROM AUTHOR]

The continent-to-ocean supply of phosphorus (P) in the soluble state, recognized as bioavailable P, via the atmosphere is hypothesized to be crucial to the biological cycle in offshore surface seawater. To investigate the solubility of P in aerosol particles moving towards the Northwestern Pacific from the Asian continent, we measured the total P (TP), total dissolved P (TDP) and dissolved inorganic P (DIP) in aerosols at Qingdao (36°06' N, 120°33' E), a coastal city in eastern China. The samples were collected in December 2012 and January 2013 (winter) and in March and April 2013 (spring), when the middle latitude westerly wind was prevailing. On average, P solubility, i.e., the ratio of TDP to TP, was 32.9 ± 16.7 % in winter and 21.3 ± 9.8 % in spring, and the TP concentrations in the two seasons were similar. This seasonal solubility difference is attributed to the aerosol sources containing the P. Particles in winter were predominantly anthropogenic particles from local and regional areas, and particles in spring were significantly influenced by natural dust from the arid and semiarid areas in the inland part of the continent. Moreover, acidification processes associated with the formation of sulfate and nitrate in the winter samples enhanced P solubility, suggesting that the P in anthropogenic particles was more susceptible to the production of acidic species than that in natural dust particles. There was a strong positive correlation between P solubility and relative humidity (RH). P solubility was usually less than 30 % when RH was below 60 %, even when the content of acidic species and/or anthropogenic particles in the aerosols was high, suggesting humidity had a critical role in the production of TDP. In addition, the proportion of DIP in TDP was high when the particles were predominantly anthropogenic, and the proportion of dissolved organic P (DOP; quantified as TDP-DIP) in TDP was high when the particles were dominated by natural dust. These results indicate that, as the contents of bioavailable P in Asian continent outflows are closely dependent on the aerosol particle origins, atmospheric acidic processes could convert P into a bioavailable state under certain meteorological conditions. Therefore, the recent severe air pollution over East Asia might have enhanced the input of bioavailable P to downwind marine areas. [ABSTRACT FROM AUTHOR]

Utilizing a recent observational particulate matter with diameters less than 2.5 μm (PM2.5) dataset in North China, this study reveals a distinct seesaw feature of abnormally high and low PM2.5 concentrations in the adjacent two months of December 2015 and January 2016, accompanied by distinct meteorological modulations. The seesaw pattern is postulated to be linked to super El Niño and the Arctic Oscillation (AO). During the mature phase of El Niño in December 2015, the weakened East Asian Winter Monsoon (EAWM) and the associated low-level southerly wind anomaly reduced planetary boundary layer height, favoring strong haze formation. This circulation pattern was completely reversed in the following month, in part due to a sudden phase change of the AO from positive to negative and the beginning of a decay of the El Niño, which enhanced the southward shift of the upper-tropospheric jet from December to January relative to climatology, leading to an enhanced EAWM and substantially lower haze formation. This sub-seasonal change in circulation is also robustly found in 1982/1983 and 1997/1998, implicative of a general physical mechanism dynamically linked to El Niño and the AO. Numerical experiments with the Weather Research and Forecasting (WRF)-Community Multi-scale Air Quality (CMAQ) model were used to test the modulation of the meteorological conditions on haze formation. With the same emission, simulations for three super El Niño periods (1983, 1997 and 2015) robustly show higher PM2.5 concentrations under the mature phase of the super El Niño, but substantially lower PM2.5 concentrations during the decay phase of El Niño (and the sudden AO phase change), further verifying the modulation effect of sub-seasonal circulation anomaly on PM2.5 concentrations in North China. [ABSTRACT FROM AUTHOR]

Abstract Atmospheric deposition of long range transport anthropogenic reactive nitrogen (Nr, mainly NHx, NOy and water-soluble organic nitrogen (WSON)) from continent exerts profound impact on marine biogeochemistry. On the other hand, marine biogenic dissolve organic nitrogen (DON) is also a potential contributor to aerosol WSON in overlying atmosphere. Despite of the importance of off-continent dispersion and interactive processes of Nr in the atmosphere-ocean boundary, knowledge regarding sources of various nitrogen species in the open ocean remained limited due to insufficient observations. In spring of 2014 and 2015, we conducted two cruises starting from the coast of China through the East China Seas (ECSs, i.e. Yellow Sea and East China Sea) to the open ocean (i.e. Northwest Pacific Ocean, NWPO). Concentrations of water-soluble total nitrogen (WSTN), NO3- and NH4+, and δ15N of WSTN and NO3- in marine aerosol were measured for both cruises. In spring of 2015, we also analysed the aerosol CHON molecular formulas by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and the concentrations and δ15N of NO3- and DON of surface sea water (SSW) (depth 5 m) along the cruise track. Aerosol NO3-, NH4+ and WSON showed a logarithmic off shore decrease pattern (1-2 orders of magnitude drop) reflecting a strong anthropogenic emission source of NO3-, NH4+ and WSON from China. Concentrations of aerosol NO3- and NH4+ were significantly higher in 2014 (even in remote NWOP) than those in 2015 due to stronger wind field in 2014, underscoring the role of the Asian winter monsoon in seaward transport of anthropogenic NO3- and NH4+. However, the WSON in background aerosol over the NWPO in 2015 (12.7 ± 8.7 nmol m-3) was close to that in 2014 (10.7 ± 7.0 nmol m-3) suggesting an addition of non-anthropogenic WSON source in the open ocean. Results of the FT-ICR-MS analyses revealed a higher contribution of marine biological source to WSON in background aerosol and this was supported by the analysis of isotopic mixing between aerosol NH4+ and SSW DON (5.8 ± 2.0 ‰). Obviously, the marine DON emission should be considered in model and field work while assessing the net atmospheric WSON deposition in the open ocean. This is the first hand parallel dataset for isotopic compositions of marine DON and aerosol Nr, more studies are required to explore the complicated processes of sources and deposition of Nr to advance our knowledge of the anthropogenic influence on marine nitrogen cycle and nitrogen exchanges through the land-ocean and the air-sea interface. [ABSTRACT FROM AUTHOR]

Actinidia eriantha Benth. is a diploid perennial woody vine native to China and is recognized as a valuable species for commercial kiwifruit improvement with high levels of ascorbic acid as well as having been used in traditional Chinese medicine. Due to the lack of genomic resources for the species, microsatellite markers for population genetics studies are scarce. In this study, RNASeq was conducted on fruit tissue of A. eriantha, yielding 5,678,129 reads with a total output of 3.41 Gb. De novo assembly yielded 69,783 non-redundant unigenes (41.3 Mb), of which 21,730 were annotated using protein databases. A total of 8,658 EST-SSR loci were identified in 7,495 unigene sequences, for which primer pairs were successfully designed for 3,842 loci (44.4%). Among these, 183 primer pairs were assayed for PCR amplification, yielding 69 with detectable polymorphism in A. eriantha. Additionally, 61 of the 69 polymorphic loci could be successfully amplified in at least one other Actinidia species. Of these, 14 polymorphic loci (mean NA = 6.07 ± 2.30) were randomly selected for assessing levels of genetic diversity and population structure within A. eriantha. Finally, a neighbor-joining tree and Bayesian clustering analysis showed distinct clustering into two groups (K = 2), agreeing with the geographical distributions of these populations. Overall, our results will facilitate further studies of genetic diversity within A. eriantha and will aid in discriminating outlier loci involved in local adaptation. [ABSTRACT FROM AUTHOR]

In this study, five on-board microcosm experiments were performed in the subtropical gyre, Kuroshio Extension region of the Northwest Pacific Ocean (NWPO) and the Yellow Sea (YS), in order to investigate phytoplankton growth following the addition of artificially modified mineral dust (AM-dust) and various nutrients (nitrogen-N, phosphorus-P, ironFe, N+P, and N+P+Fe). The two experiments carried out with AM-dust addition in the subtropical gyre showed a maximum chlorophyll a (Chl a) concentration increase of 1.7- and 2.8-fold, while the cell abundance of large-sized phytoplankton (>5 15 μm) showed a 1.8- and 3.9-fold increase, respectively, relative to the controls. However, in the Kuroshio Extension region and the YS, the increases in maximum Chl a and cell abundance of large-sized phytoplankton following AM-dust addition were at most 1.3-fold and 1.7-fold larger than those in the controls, respectively. A net conversion efficiency index (NCEI) newly proposed in this study, size-fractionated Chl a, and the abundance of large-sized phytoplankton were analysed to determine which nutrients contribute to support phytoplankton growth. Our results demonstrate that a combination of nutrients, NP or 20 NPFe as well as other micro-constituents, are responsible for phytoplankton growth in the subtropical gyre following AM-dust addition. Single nutrient addition, i.e., N in the Kuroshio Extension region and P/N in the YS, controls the phytoplankton growth following AM-dust addition. In the AM-dust-addition experiments, wherein the increased NP or P were identified to determine phytoplankton growth, the dissolved inorganic P from AM-dust (8.6 nmol L-1 ) was much lower than the theoretically estimated minimum P demand (∼20 nmol L-1 ) for phytoplankton growth. These observations suggest that additional supply 25 augments the bioavailable P stock in incubated seawater with AM-dust addition, most likely due to an enhanced solubility of P from AM-dust or re-mineralization of the dissolved organic P. [ABSTRACT FROM AUTHOR]

In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of the euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not well established. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions of a specified nutrient--phytoplankton model. The model is well suited to explain basic dependencies between a nitracline and an SCML. The analytical solution shows that the nitracline depth is deeper than the depth of the SCML, shoaling with an increase in the light attenuation coefficient and with a decrease in surface light intensity. The inverse proportional relationship between the light level at the nitracline depth and the maximum rate of new primary production is derived. Analytic solutions also show that a thinner SCML corresponds to a steeper nitracline. The nitracline steepness is positively related to the light attenuation coefficient but independent of surface light intensity. The derived equations of the nitracline in relation to the SCML provide further insight into the important role of the nitracline in marine pelagic ecosystems. [ABSTRACT FROM AUTHOR]

This study is the first time to use two identical Fast Mobility Particle Sizers for simultaneously measuring particle number size distributions (PNSD) at a street site and a rooftop site within 500 m distance in winter and spring times in Beijing. The obtained datasets in 1-second time resolution allow reasonably deducting the freshly emitted traffic particle signal from the measurements at the street site and thereby pave the way to study reduced or enhanced effects on new particle formation (NPF) in urban atmospheres through the site-by-site comparison. The number concentration of newly formed particles, i.e., smaller than 20 nm, and the NPF rate in the springtime were smaller at the street site than at the rooftop site. In contrast, NPF was enhanced in the wintertime at the street site with NPF rates increased by 3-5 times, characterized by a shorter NPF time and higher new particle yields than those at the rooftop site. Our results imply that the street canyon likely exerts distinct seasonal effects on NPF because of on-road vehicle emissions, i.e., stronger condensation sinks that may be responsible for reduced NPF in the springtime but efficient nucleation and partitioning of gaseous species that contribute to the enhanced NPF in the wintertime. We also analyzed the occurrence or absence of apparent growth for > 10 nm new particles. The oxidization of biogenic organics in the presence of strong photochemical reactions was argued to play an important role in growing > 10 nm new particles, but sulfuric acid was unlikely the crucial specie for the apparent growth. [ABSTRACT FROM AUTHOR]

Interannual variabilities in atmospheric ammonia (NH3) during the most recent 7-11 years were investigated at 14 sites across North America using the monitored data obtained from NAPS, CAPMoN and AMoN networks. The long-term average of atmospheric NH3 ranged from 0.8 to 2.6 ppb, depending on location, at four urban and two rural/ agricultural sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission. An increasing trend was actually identified from 2003 to 2014 at the downtown Toronto site using either the Mann-Kendall or the ensemble empirical mode decomposition method, but "no" or "stable" trends were identified at other sites. The ~20% increase during the 11-year period at the site was likely caused by changes in NHC+4 -NH3 partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature. The long-term average from 2008 to 2015 was 1.6-4.9 ppb and 0.3-0.5 ppb at four rural/agricultural and at four remote US sites, respectively. A stable trend in NH3 mixing ratio was identified at one rural/ agricultural site while increasing trends were identified at three rural/agricultural (0.6-2.6 ppb, 20-50% increase from 2008 to 2015) and four remote sites (0.3-0.5 ppb, 100-200% increase from 2008 to 2015). Increased ambient temperature was identified to be a cause for the increasing trends in NH3 mixing ratio at four out of the seven US sites, but what caused the increasing trends at other US sites needs further investigation. [ABSTRACT FROM AUTHOR]

In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not well established. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions for the system of phytoplankton and nutrient. The analytical solution shows that the nitracline depth is deeper than the depth of SCML, shoaling with an increase in light attenuation coefficient and with a decrease in surface light intensity. The inverse proportional relationship between the light level at the nitracline depth and the maximum rate of new primary production is derived, suggesting that the light level at the nitracline can be used as an indicator for integrated new primary production. Analytic solutions also show that a thinner SCML corresponds to a steeper nitracline. The nitracline steepness is positively related to light attenuation coefficient, but independent of surface light intensity. The derived equations of the nitracline in relation to the SCML provide further insight into the important role of the nitracline in marine pelagic ecosystems. [ABSTRACT FROM AUTHOR]

Interannual variabilities in atmospheric ammonia (NH3) during the most recent seven to eleven years were investigated at fourteen sites across North America using the monitored data obtained from NAPS, CAPMoN and AMoN networks. The long-term average of atmospheric NH3 ranged from 0.8 to 2.6 ppb, depending on location, at four urban and two rural/agriculture sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission. An increasing trend was actually identified from 2003 to 2014 at the downtown Toronto site using either the Mann-Kendall or the Ensemble Empirical Mode Decomposition method, but "no" or "stable" trends were identified at other sites. The ~20 % increase during the 11-year period at the site was likely caused by changes in NH4+/NH3 partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature. The long-term average from 2008 to 2015 was 1.6-4.9 ppb and 0.3-0.5 ppb at four rural/agriculture and at four remote U.S. sites, respectively. A stable trend in NH3 mixing ratio was identified at one rural/agricultural site while increasing trends were identified at three rural/agricultural (0.6-2.6 ppb, 20-50 % increase from 2008-2015) and four remote sites (0.3-0.5 ppb, 100-200% increase from 2008-2015). Increased ambient temperature was identified to be a cause for the increasing trends in NH3 mixing ratio at four out of the seven U.S. sites, but what caused the increasing trends at other U.S. sites needs further investigation. [ABSTRACT FROM AUTHOR]

Interannual variabilities in atmospheric ammonia (NH3) during the most recent seven to eleven years were investigated at fourteen sites across North America using the monitored data obtained from NAPS, CAPMoN and AMoN networks. The long-term average of atmospheric NH3 ranged from 0.8 to 2.6 ppb, depending on location, at four urban and two rural/agriculture sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission. An increasing trend was actually identified from 2003 to 2014 at the downtown Toronto site using either the Mann-Kendall or the Ensemble Empirical Mode Decomposition method, but "no" or "stable" trends were identified at other sites. The ~20% increase during the 11-year period at the site was likely caused by changes in NH4+/NH3 partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature. The long-term average from 2008 to 2015 was 1.6-4.9 ppb and 0.3-0.5 ppb at four rural/agriculture and at four remote U.S. sites, respectively. A stable trend in NH3 mixing ratio was identified at one rural/agricultural site while increasing trends were identified at three rural/agricultural (0.6-2.6 ppb, 20-50% increase from 2008-2015) and four remote sites (0.3-0.5 ppb, 100-200% increase from 2008-2015). Increased ambient temperature was identified to be a cause for the increasing trends in NH3 mixing ratio at four out of the seven U.S. sites, but what caused the increasing trends at other U.S. sites needs further investigation. [ABSTRACT FROM AUTHOR]

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Kiwifruit (Actinidia chinensis Planchon) is an important specialty fruit crop that suffers from narrow genetic diversity stemming fromrecent global commercialization and limited cultivar improvement. Here, we present high-density RAD-seq-based geneticmaps using an interspecific F1 cross between Actinidia rufa 'MT570001' and A. chinensis 'Guihai No4'. The A. rufa (maternal) map consists of 2,426 single-nucleotide polymorphism (SNP)markers with a total length of 2,651 cM in 29 linkage groups (LGs) corresponding to the 29 chromosomes. The A. chinensis (paternal) map consists of 4,214 SNPmarkers over 3,142 cMin 29 LGs. Using these maps, we were able to anchor an additional 440 scaffolds from the kiwifruit draft genome assembly. Kiwifruit is functionally dioecious, which presents unique challenges for breeding and production. Three sex-specific simple sequence repeats (SSR) markers can be used to accurately sex type male and female kiwifruit in breeding programmes. The sex-determination region (SDR) in kiwifruit was narrowed to a 1-Mb subtelomeric region on chromosome 25. Localizing the SDR will expedite the discovery of genes controlling carpel abortion in males and pollen sterility in females. [ABSTRACT FROM AUTHOR]

Background and Aims: The phylogeography of plant species in sub-tropical China remains largely unclear. This study used Tapiscia sinensis, an endemic and endangered tree species widely but disjunctly distributed in sub-tropical China, as a model to reveal the patterns of genetic diversity and phylogeographical history of Tertiary relict plant species in this region. The implications of the results are discussed in relation to its conservation management. Methods: Samples were taken from 24 populations covering the natural geographical distribution of T. sinensis. Genetic structure was investigated by analysis of molecular variance (AMOVA) and spatial analysis of molecular variance (SAMOVA). Phylogenetic relationships among haplotypes were constructed with maximum parsimony and haplotype network Methods. Historical population expansion events were tested with pairwise mismatch distribution analysis and neutrality tests. Species potential range was deduced by ecological niche modelling (ENM). Key Results: A low level of genetic diversity was detected at the population level. A high level of genetic differentiation and a significant phylogeographical structure were revealed. The mean divergence time of the haplotypes was approx. 1·33 million years ago. Recent range expansion in this species is suggested by a star-like haplotype network and by the results from the mismatch distribution analysis and neutrality tests. Conclusions: Climatic oscillations during the Pleistocene have had pronounced effects on the extant distribution of Tapiscia relative to the Last Glacial Maximum (LGM). Spatial patterns of molecular variation and ENM suggest that T. sinensis may have retreated in south-western and central China and colonized eastern China prior to the LGM. Multiple montane refugia for T. sinense existing during the LGM are inferred in central and western China. The populations adjacent to or within these refugia of T. sinense should be given high priority in the development of conservation policies and management strategies for this endangered species. [ABSTRACT FROM AUTHOR]

To determine the influence of red yeast rice on production performance, egg quality and serum traits of laying hens, 288 laying hens (40-week-old) were randomly assigned into four groups with 6 replications of 12 birds each. Hens were provided with diets containing 0, 0.5, 1 and 5 g/kg red yeast rice for 8- weeks. Results showed that dietary supplementation of red yeast rice had no effect (P>0.05) on laying performance over the entire feeding period. Albumen height (quadratic, cubic, P<0.05) and Haugh units (quadratic, P<0.05) were increased with gradient addition of red yeast rice. Moreover, albumen height and Haugh units were higher (P<0.05) in 1 and 5 g/kg red yeast rice groups, with an exception of albumen height in 1 g/kg group at day 28. Yolk cholesterol content was lower (P<0.05) in 5 g/kg red yeast rice-supplemented group at day 56. There were decreased (P<0.05) contents of serum cholesterol and triglyceride, but higher (P<0.05) concentration of serum calcium in the 1 and 5 g/kg red yeast rice-treated hens compared with the control group. Serum level of very-low-density lipoprotein was also reduced (P<0.05) in 5 g/kg red yeast rice-treated hens. The results suggest that red yeast rice could lower serum and egg yolk cholesterol levels and improve the egg quality in laying hens. [ABSTRACT FROM AUTHOR]

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics. [ABSTRACT FROM AUTHOR]

The whole complete chloroplast (cp) genome sequence of Actinidia kolomikta (formerly A. maloide) was sequenced and assembled from Illumina paired-end sequencing. The cp genome of A. arguta was 157,425 bp long, containing a large single copy region (LSC) of 88,498 bp and a small single copy region (SSC) of 20,475 bp and a pair of inverted repeat regions (IR) of 242,266 bp. It contained 113 different genes, including 79 protein-coding genes, 30 tRNA genes, 4 ribosomal RNA genes. Phylogenetic analysis using concatenated alignments of whole cp genome sequences revealed that A. kolomikta was the sister group to all other groups of Actinidia [ABSTRACT FROM AUTHOR]

Grown nucleated particles > 50 nm in diameter are an important source of cloud condensation nuclei (CCN) and when the size is > 100 nm, they can also have direct influence on the climate. In this study, the nucleation and growth of new particles in the atmosphere in Hong Kong were investigated during dry season (monthly averaged RH < 75%). The maximum size of grown nucleated particles was generally less than 40 nm during new particle burst and growth events. The exception, accounting for ∼ 20% of all burst and growth events, was those induced by strong photochemical reactions, in which subsequent particle shrinkage occurred. Temporal particle and gas concentration variability and meteorological conditions support the occurrence of particle shrinkage. The shrinkage rate calculated (∼ 8 nm h-1) was close to the growth rate. The observation of particle shrinkage sheds new light on particle transformation dynamics and it would add to the understanding of particle behavior in the atmosphere. [ABSTRACT FROM AUTHOR]

Eleven polymorphic microsatellite loci were isolated and characterized from an AC-enriched genomic library of Akebia trifoliate ssp. australis. The number of allele per locus ranged from 3 to 14. The observed heterozygosity and expected heterozygosity at population level were 0.196-1.000 and 0.522-0.902, respectively. In addition, this set of microsatellites produced robust crossspecies amplification in other two related taxa, suggesting these microsatellite markers should provide a useful tool for genetic and conservation studies of the Akebia species. [ABSTRACT FROM AUTHOR]

Recently, a variety of ion-chromatography-based semi-continuous particle instruments such as the Dionex gas particle ion chromatograph (GP-IC), wet-annular denuder/steam-jet aerosol collector (WAD/SJAC), particle-into-liquid sampler with ion chromatograph (PILS-IC), gas and aerosol monitoring system (GAMS) have been introduced for measuring particle chemical components in the atmosphere. It has been reported that sulfate concentrations in PM2.5measured by these semi-continuous particle instruments correlate well with those measured by other semi-continuous instruments such as the Aerodyne aerosol mass spectrometer (AMS), R&P 8400S and R&P 8400N analyzers, and Thermo model 5020 sulfate particle analyzer and at times exhibit a unity slope. However, the sulfate concentration measured by some of these semi-continuous instruments has been reported to be underestimated by 20–50%, as compared to that in PM2.5filter samples. In this study, numerous potential causes for underestimation of the sulfate concentrations by the GP-IC were investigated. We found a 30–40% negative artifact arising from an improper calibration procedure inherent within the instrument design. An improved calibration procedure was developed and it substantially reduced the sulfate concentration difference between the GP-IC measurements and PM2.5filter samples from 36% to 5%. [ABSTRACT FROM AUTHOR]

• Polymorphic simple sequence repeat (SSR) markers were used to investigate the impact of habitat fragmentation on the population structure and gene flow of Changiostyrax dolichocarpa, a critically endangered tree in central China. • Intrapopulation genetic diversity, population structure and gene flow in the five extant populations of this species were analysed by eight SSR markers. • Intrapopulation genetic diversity results suggest that C. dolichocarpa remnants maintained a relatively high degree of genetic diversity despite severe fragmentation. Low genetic differentiation among populations was found based on Wright's FST andamova analysis. Both the FST-based estimate and private allele method revealed high historical gene flow among the remnant populations. Recent immigrants, detected by assignment tests, tend to decrease from the grandparent generation to the current generation. • The potentially highly restricted current gene flow among fragments may render the fragmented populations of C. dolichocarpa at a higher risk of local extinction several generations after fragmentation. Both in situ and ex situ conservation management for the remnant populations of C. dolichocarpa are therefore urgently needed to rescue remaining genetic diversity. [ABSTRACT FROM AUTHOR]

Abstract??Synucleins are emerging as central players in the fundamental neural processes and in the formation of pathologically insoluble deposits characteristic of neurodegenerative diseases. However, synuclein ? (SNCG), previously identified as a breast cancer specific gene (BCSG1), is also highly expressed in breast carcinomas, but not expressed in normal or benign breast tissues. We analyzed SNCG gene expression in 93 clinical breast specimens and associated it with clinical outcome. Overall SNCG mRNA expression was detectable in 36% breast cancers. However, 81% of stage III/IV breast cancers were positive for SNCG expression, while only 15% of stage I/II breast cancers were positive for SNCG expression. In contrast, SNCG was undetectable in benign breast lesions. Expression of SNCG in the primary tumor also significantly associated with lymph node involvement and metastasis. There was no significant correlation between SNCG gene expression and age, menstruation, and status of ER, PR, PCNA, and HER-2. Patients whose tumors expressed SNCG had a significantly shorter DFS and a high probability of death when compared with those whose tumors did not express SNCG. The hazard ratio of metastasis or recurrence according to the SNCG status was 4.515 (95% CI, 1,188?17.154;P?=?0.027). Cox multivariate analysis showed that SNCG had independent prognostic significance above and beyond conventional variables. This study suggests that the expression of SNCG is an independent predictive marker for recurrence and metastasis in breast cancer progression. SNCG is expected to be a useful marker for breast cancer progression and a potential target for breast cancer treatment. [ABSTRACT FROM AUTHOR]

Fourteen polymorphic microsatellite loci in the endangered fern Adiantum reniforme var. sinense were developed and characterized using the Fast Isolation by AFLP of Sequences Containing repeats (FIASCO) protocol. Polymorphism of each locus was assessed in a bulked sample of 30 individuals from 8 natural populations. The number of alleles per locus varied from 2 to 11, with an average value of 6.2. The ranges of observed and expected heterozygosity were 0.000–0.895 and 0.226–0.868, respectively. These microsatellite markers provide useful tools for the ongoing conservation genetic studies of Adiantum reniforme var. sinense. [ABSTRACT FROM AUTHOR]

Twenty-four polymorphic microsatellite loci were isolated and characterized from an AAG-enriched genomic library of Sinojackia xylocarpa. The average allele number of these microsatellites was 3.3 per locus, ranging from two to seven. The observed and expected heterozygosities at population level were 0.10–0.83 and 0.10–1.00, respectively. In addition, successful cross-species amplification of this set of microsatellites in three other species of Sinojackia and a closely related taxon, Changiostyrax dolichocarpa, suggested that this set of microsatellite markers should provide a useful tool for genetic and conservation studies of Sinojackia species and other closely related taxa in the Styracaceae. [ABSTRACT FROM AUTHOR]

Focuses on the use of generalized logistic model of individual tree mortality for trembling aspen, white spruce and lodgepole pine. Determination on the survival probability of an individual tree; Stand characteristics of trees; Estimation of species-specific site productivity index.

This paper provides a profile of Dutch outbound travellers by the volume of expenditure segments including light, medium and heavy spenders. Significant differences are found among the spender categories in the descriptive variables which include sociodemographics, travel characteristics, travel philosophies, participated travel activites, and travel benefits sought. Based on the results, suggestions are given on targeting different spender groups for international travel marketers. [ABSTRACT FROM PUBLISHER]

Nine polymorphic microsatellite loci were isolated and characterized from an AC-enriched genomic library of Disanthus cercidifolius var. longipes. Microsatellite polymorphism was investigated using 24 individuals from one natural population. The observed number of alleles per locus ranged from two to four. Observed and expected heterozygosities ranged from 0.17 to 0.92 and from 0.16 to 0.72, respectively. These polymorphic microsatellite loci provide useful tools for the ongoing population genetic studies of D. cercidifolius var. longipes. [ABSTRACT FROM AUTHOR]

Fourteen polymorphic microsatellite loci were isolated and characterized from an AC-enriched genomic library of Liriodendron chinense (Magnoliaceae). The average allele number of these microsatellites was 5.2 per locus, ranging from three to eight. The observed and expected heterozygosity at population level were 0.07-1.00 and 0.10-0.83, respectively. These sets of microsatellites will be useful for studies of population genetic structure of L. chinense and L. tulipifera as well as to estimate finescale gene flow rates. [ABSTRACT FROM AUTHOR]