A new differential evolution (DE) algorithm, JADE, is proposed to improve optimization performance by implementing a new mutation strategy ldquoDE/current-to- p bestrdquo with optional external ...archive and updating control parameters in an adaptive manner. The DE/current-to- p best is a generalization of the classic ldquoDE/current-to-best,rdquo while the optional archive operation utilizes historical data to provide information of progress direction. Both operations diversify the population and improve the convergence performance. The parameter adaptation automatically updates the control parameters to appropriate values and avoids a user's prior knowledge of the relationship between the parameter settings and the characteristics of optimization problems. It is thus helpful to improve the robustness of the algorithm. Simulation results show that JADE is better than, or at least comparable to, other classic or adaptive DE algorithms, the canonical particle swarm optimization, and other evolutionary algorithms from the literature in terms of convergence performance for a set of 20 benchmark problems. JADE with an external archive shows promising results for relatively high dimensional problems. In addition, it clearly shows that there is no fixed control parameter setting suitable for various problems or even at different optimization stages of a single problem.
O3 and PM2.5 were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China＇s urban air quality will ...be evaluated using six factors （SO2, NO2, O3, CO, PM2.5 and PM10） from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2 and PMlo were observed in 26 cities, and the pollutants O3, CO and PM2.5 were measured in 15 of the 26 cities. The concentrations of SO2 and CO were much higher in the cities in north China than those in the south. As for O3 and NO2, however, there was no significant difference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5 to PMI0 ranging from 55% to 77%. The concentrations of PM2.5 （57.5 μg/m3） and PMlo （91.2 μg/m3） were much higher than the values （PM2.5：11.2μg/m3; PMI0：35.6 μg/m3） recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more efforts will to be taken to control air pollution in China.
Mudrocks buried at different depths in a single well exhibiting different sedimentary environments and lithologies were collected from the Dongying Sag of the Jiyang Depression of eastern China to ...investigate the heterogeneities of organic matter (OM) and its occurrence forms. In this study, both bulk rocks and their organo-clay composites (i.e., <2 μm clay-sized fractions) were subjected to palynofacies analysis. The results demonstrate that palynological OM abundance and total organic carbon (TOC) content for bulk rocks are positively correlated with those in organo-clay composites respectively, suggesting that the palynological OM in organo-clay composites is intimately related to that in bulk rocks. However, other numerous variations between them exist: a) OM in the organo-clay composites is aquatic and prone to type I, while it is both terrestrial and aquatic and has multiple types of OM in bulk rocks; b) the palynological organic components in the organo-clay composites, which are mostly amorphous OM (AOM) with an average abundance exceeding 90%, are substantially different from those in bulk rocks, which possess both AOM and terrestrial OM (palynomorphs and structured OM); and c) at different depths, sedimentary environments and lithologies, the percentages of individual palynological organic components are relatively stable in organo-clay composites, whereas they vary over a wide range in bulk rocks. As many previous studies have indicated that OM occurrence is dominantly in the form of organo-clay composites, our results reveal that OM in mudrocks is heterogeneous with respect to its components and occurrence forms, namely, free OM and organo-clay composites, within which OM is greatly varied in association with minerals and its palynofacies. Free OM is physically coexisted with minerals and has different palynological organic components, while OM in organo-clay composites is combined with minerals and is dominantly composed of AOM. Our work demonstrates that OM occurrence in mudrocks has two distinct forms and their palynological organic components are greatly varied, which should be concerned in studies of source rock for further understanding the source material of petroleum.
•Comparisons of palynofacies between mudrocks and their organo-clay composites were performed.•Components, types and origins of palynological OM are diverse in bulk rocks while are simplex in organo-clay composites.•OM in mudrocks has two occurrence forms: free OM and organo-clay composites.
To elucidate the air pollution characteristics of northern China, airborne PM10 (atmospheric dynamic equivalent diameter≤10μm) and PM2.5 (atmospheric dynamic equivalent diameter≤2.5μm) were sampled ...in three different functional areas (Yuzhong County, Xigu District and Chengguan District) of Lanzhou, and their chemical composition (elements, ions, carbonaceous species) was analyzed. The results demonstrated that the highest seasonal mean concentrations of PM10 (369.48μg/m3) and PM2.5 (295.42μg/m3) were detected in Xigu District in the winter, the lowest concentration of PM2.5 (53.15μg/m3) was observed in Yuzhong District in the fall and PM10 (89.60μg/m3) in Xigu District in the fall. The overall average OC/EC (organic carbon/elemental carbon) value was close to the representative OC/EC ratio for coal consumption, implying that the pollution of Lanzhou could be attributed to the burning of coal. The content of SNA (the sum of sulfate, nitrate, ammonium, SNA) in PM2.5 in Yuzhong County was generally lower than that at other sites in all seasons. The content of SNA in PM2.5 and PM10 in Yuzhong County was generally lower than that at other sites in all seasons (0.24–0.38), indicating that the conversion ratios from precursors to secondary aerosols in the low concentration area was slower than in the area with high and intense pollutants. Six primary particulate matter sources were chosen based on positive matrix factorization (PMF) analysis, and emissions from dust, secondary aerosols, and coal burning were identified to be the primary sources responsible for the particle pollution in Lanzhou.
The chemical composition of PM10 and PM2.5, including element, water-soluble irons and carbonaceous species were analyzed and the source apportionment of particles was calculated in three functional areas. The conclusion supported that emissions from dust related, secondary aerosols, and coal burning were the primary sources of air pollution in Lanzhou. Display omitted
Polarized Rac1 signaling is a hallmark of many cellular functions, including cell adhesion, motility, and cell division. The two steps of Rac1 activation are its translocation to the plasma membrane ...and the exchange of nucleotide from GDP to GTP. It is, however, unclear whether these two processes are regulated independent of each other and what their respective roles are in polarization of Rac1 signaling. We designed a single-particle tracking (SPT) method to quantitatively analyze the kinetics of Rac1 membrane translocation in living cells. We found that the rate of Rac1 translocation was significantly elevated in protrusions during cell spreading on collagen. Furthermore, combining FRET sensor imaging with SPT measurements in the same cell, the recruitment of Rac1 was found to be polarized to an extent similar to that of the nucleotide exchange process. Statistical analysis of single-molecule trajectories and optogenetic manipulation of membrane lipids revealed that Rac1 membrane translocation precedes nucleotide exchange, and is governed primarily by interactions with phospholipids, particularly PI(3,4,5)P ₃, instead of protein factors. Overall, the study highlights the significance of membrane translocation in spatial Rac1 signaling, which is in addition to the traditional view focusing primarily on GEF distribution and exchange reaction.
Significance Rac1 activation involves two steps: translocation to plasma membrane and nucleotide exchange. Most previous studies focused on the nucleotide exchange cycle. Here we sought to understand membrane translocation dynamics by developing a single-particle tracking-based method. The labeled Rac1 molecules were further adapted for simultaneous FRET sensing of Rac1 nucleotide state, enabling a simultaneous comparison between Rac1 translocation dynamics and its nucleotide exchange dynamics. Elevated membrane recruitment can contribute significantly to polarized Rac1-signaling. This finding draws attention to the importance of spatial regulation of the Rac1 translocation process in the regulation of RhoGTPase signaling. Rac1 recruitment to membrane precedes its interaction with protein factors (e.g., GEFs) and is governed by phospholipid distributions. This finding resolves a long-standing question of the mechanism of Rac1 activation.
Mudrocks formed in different sedimentary environments of the Dongying Sag (eastern China) were used for the analyses and measurements of specific surface area, X-ray diffraction, palynofacies and ...pyrolysis, to examine the correlations and influencing factors of different organic components with specific surface areas (SSAs) in mudrocks. The results indicate that total organic matter in the mudrocks is composed of amorphous organic matter (AOM) and morphological organic matter (MOM, palynomorphs plus structured organic matter). Specific surface areas in mudrock consist of inner and external surface areas. The ratio of AOM/MOM and characteristics of inner and external surface areas are varied in different mudrocks. The relationships between SSAs and organic matter of which the occurrence of different organic components are not consistent: organic matter in MOM-dominated mudrocks is negatively correlated with external, inner and total surface areas, which are related to the MOM occurring independently as organic particles without being adsorbed onto mineral surfaces; organic matter in mudrocks dominated by the AOM is negatively correlated with external surface area and positively correlated with inner and total surface areas, which are ascribed to the more feasible adsorption of the AOM on mineral surfaces (particularly the inner surface) and the adsorption of the MOM on mineral surfaces in the form of fine particulate organic matter. In addition, the combination of organic components (including the AOM and MOM) with carbonates has an effect on the relationships between SSAs and organic matter. Therefore, the organic component morphology and mode of occurrence in mudrock have an influence on the relevance of total organic carbon (TOC) with specific surface areas. Further study on the relationships between TOC and specific surface areas of mudrocks is of great significance to reveal the occurrence mechanisms of organic matter and unconventional petroleum and to assess the effectiveness and persistence of carbon sequestration.
•Organic matter (OM) is composed of amorphous and morphological organic matters.•Specific surface areas (SSAs) consist of inner and external surface areas.•Organic component occurrences influence the relationships between OM and SSAs.•This study is important for understanding organic matter occurrences in mudrocks.
Pollutants emission, meteorological conditions, secondary formation, and pollutants transport are the main reasons for air pollution. A comprehensive air pollution analysis was conducted from the ...above four aspects in the autumn–winter seasons of 2017–2018 and 2018–2019 at Xingtai, China. In addition, the relationship between PM2.5 and O3 was also studied from the aspects of secondary formation and meteorological conditions to find the rules of cooperative management of PM2.5 and O3 combined pollution. Taking measures of concentrated and clean heating and controlling biomass burning could make the concentrations of EC, K+ and SO42− decrease. The variation trends of PM2.5 and O3 concentration in the autumn–winter season of Xingtai were different, and with the increase in secondary formation effects, the concentration of O3 decreased. Furthermore, the key meteorological conditions that affected O3 and PM2.5 formation were temperature and relative humidity, respectively. The relationships of NOR (nitrate oxidation rate) and SOR (sulfate oxidation rate) against temperature presented a “U” shape, suggesting that gas-phase oxidation and gas–solid-phase oxidation were all suppressed at a temperature of around 4 °C. The cities located in the east had more pollutant transporting effects during the pollution processes of Xingtai, and the main transport routes of O3 and PM2.5 were not all the same.
Statistical transition probability matrices (TPMs), which indicate the likelihood of obligor credit state migration over a certain time horizon, have been used in various credit decision-making ...applications. A standard approach of calculating TPMs is to form a one-year empirical TPM and then project it into the future based on Markovian and time-homogeneity assumptions. However, the one-year empirical TPM calculated from historical data generally does not satisfy desired properties. We propose an alternative methodology by formulating the problem as a constrained optimization problem requiring satisfaction of all the desired properties and minimization of the discrepancy between predicted multi-year TPMs and empirical evidence. The problem is high-dimensional, non-convex, and non-separable, and is not effectively solved by nonlinear programming methods. To address the difficulty, we investigated evolutionary algorithms (EAs) and problem representation schemas. A self-adaptive differential evolution algorithm JADE, together with a new representation schema that automates constraint satisfaction, is shown to be the most effective technique.
Summary
Dormant bacterial spores are extraordinarily resistant to environmental insults and are vectors of various illnesses. However, spores cannot cause disease unless they germinate and become ...vegetative cells. The molecular details of initiation of germination are not understood, but proteins essential in early stages of germination, such as nutrient germinant receptors (GRs) and GerD, are located in the spore inner membrane. In this study, we examine how these germination proteins are organized in dormant Bacillus subtilis spores by expressing fluorescent protein fusions that were at least partially functional and observing spores by fluorescence microscopy. We show that GRs and GerD colocalize primarily to a single cluster in dormant spores, reminiscent of the organization of chemoreceptor signalling complexes in Escherichia coli. GRs require all their subunits as well as GerD for clustering, and also require diacylglycerol addition to GerD and GRs' C protein subunits. However, different GRs cluster independently of each other, and GerD forms clusters in the absence of all the GRs. We predict that the clusters represent a functional germination unit or ‘germinosome’ in the spore inner membrane that is necessary for rapid and cooperative response to nutrients, as conditions known to block nutrient germination also disrupt the protein clusters.
To analyze the change of CT texture features of esophageal squamous cell carcinoma (ESC) during RT delivery and to correlate these changes with the RT responses and survival.
A total of 61 ESC ...patients received radical RT were screened. Weekly CTs (4-6 sets for each patient) were acquired during RT. The tumors, normal esophageal mucosa tissue (NEC) of 5 cm and the spinal cord in the relevant area were delineated. CT texture features were extracted with a home-made tool. The changes of these features were analyzed by t-test. The correlations of the changes of features with RT responses and with patient survival were investigated by Pearson analysis.
The average changes were increased by 0.00072 ±0.00197 for coarseness, by 0.14 ±0.40 for entropy, and by 2.34 ±3.56 for strength. In addition, the average changes were reduced by 8.88 ±15.71cc for volume and by 0.07 ±0.11 for busyness. The changes of the coarseness, strength, STD and entropy in ESC were different for the good and poor response groups. The survival rate of the patients was significantly correlated with the change of coarseness and strength (P = 0.0027 and P = 0.0001).
During RT, changes of CT texture features of ESC, e.g., coarseness, strength, STD, entropy and volume are correlated with radiation response and survival rate. With more clinical data and robust research, CT features, e.g., coarseness and strength, can be selected as outstanding imaging biomarkers for prediction of RT prognosis of ESC.
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