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As a soft metal, the addition of Cu has an important influence on the high-temperature tribological properties and oxidation behavior of nanomultilayered AlTiN/Cu coatings. At room temperature (RT), due to abrasive wear, the AlTiN coating exhibited a high friction coefficient of 0.97 and low wear resistance. After adding Cu layer, the friction coefficient gradually decreased to 0.59 at 18.4 at.% Cu due to the lubricating effect of soft metal Cu and CuO, and the best wear resistance was achieved at 2.9 at.% Cu. At 800 °C, the oxidation resistance sharply reduced after adding Cu layer, and exhibited oxidation delamination. At low Cu contents (≤4.5 at.%), by the inward diffusion of O, a mixed oxide layer of Al2O3, TiO2, and CuO formed. At 18.4 at.% Cu, by the outward diffusion and oxidation of Cu, double-layer oxides formed, and the top layer of CuO contributed to a low friction coefficient of 0.53, but also caused a reduce in the wear resistance.

Drought profoundly affects the morpho-physiological responses of desert plants in dryland. To scrutinize the morpho-physiological responses of nitrogen (N)-fixing legumes (Ammopiptanthus mongolicus, Caragana korshinskii), N-fixing non-legumes (Elaeagnus angustifolia, Hippophae rhamnoides), and non-N-fixing plants (Nitraria tangutorum, Haloxylon ammodendron) under varied drought stress levels (75%, 50%, 25% and 5% of soil water holding capacity), a pot experiment was conducted in greenhouse. Following prolonged water deficit, carbon (C) and N stoichiometry, metabolic rates, plant growth, and biomass distribution of unstressed and stressed plants were recorded. Intensified drought significantly reduced stem, root and whole-plant biomass, with no significant changes observed in leaf dry-fresh mass ratio, specific leaf area, intrinsic water use efficiency and root to shoot ratio. However, other traits were impacted differently, reflecting distinct adaptive strategies to drought among three plant functional types (PFTs). Patterns of trait-soil water content (SWC) relationships varied across different PFTs, with N-fixing non-legumes followed by N-fixing legumes displayed greater sensitivity to SWC variations than non-N-fixing plants. This resulted in a shift from a stronger trait-SWC relationship in N-fixing non-legumes and N-fixing legumes to a less correlated relationship in non-N-fixing plants. The diverse responses to drought among PFTs suggest a shift from N limitation to water limitation as SWC decreases.

The performance of the suspension is a crucial criterion for evaluating both vehicle handling and passenger comfort. To enhance suspension performance, this study proposes the design of a Quantum Genetic Fuzzy Sliding Mode Controller (S-QFSMC) based on the Smith predictor estimator, building upon the foundation of the vehicle magneto-rheological semi-active air suspension. According to the physical model of the vehicle suspension, a mechanical model of a quarter-vehicle magneto-rheological semi-active air suspension with time delay is established. On this basis, a conventional sliding mode controller is designed, and quantum genetic algorithm and fuzzy control principles are employed to optimize the chattering issue associated with sliding mode control. The Smith predictor estimator is utilized to effectively compensate for the time delay in the suspension system. Subsequently, a simulation analysis of the vehicle suspension performance is conducted. The results indicate that, compared to passive suspension control, both the QFSMC controller and the S-QFSMC controller improve the suspension performance, with the S-QFSMC controller exhibiting superior comprehensive improvement. This validates the effectiveness of the designed controllers.

Abstract Background Plants accomplish multiple functions by the interrelationships between functional traits. Clarifying the complex relationships between plant traits would enable us to better understand how plants employ different strategies to adapt to the environment. Although increasing attention is being paid to plant traits, few studies focused on the adaptation to aridity through the relationship among multiple traits. We established plant trait networks (PTNs) to explore the interdependence of sixteen plant traits across drylands. Results Our results revealed significant differences in PTNs among different plant life-forms and different levels of aridity. Trait relationships for woody plants were weaker, but were more modularized than for herbs. Woody plants were more connected in economic traits, whereas herbs were more connected in structural traits to reduce damage caused by drought. Furthermore, the correlations between traits were tighter with higher edge density in semi-arid than in arid regions, suggesting that resource sharing and trait coordination are more advantageous under low drought conditions. Importantly, our results demonstrated that stem phosphorus concentration (SPC) was a hub trait correlated with other traits across drylands. Conclusions The results demonstrate that plants exhibited adaptations to the arid environment by adjusting trait modules through alternative strategies. PTNs provide a new insight into understanding the adaptation strategies of plants to drought stress based on the interdependence among plant functional traits.

Drinking water is closely related to human health, disease and mortality, and contaminated drinking water causes 485,000 deaths from diarrhea each year worldwide. China has been facing increasingly severe water scarcity due to both water shortages and poor water quality. Ensuring safe and clean drinking water is a great challenge and top priority, especially for China with 1.4 billion people. In China, more than 4000 centralized drinking water sources including rivers, lakes and reservoirs, and groundwater have been established to serve urban residents. However, there is little knowledge on the percentage, serving population and water quality of three centralized drinking water source types. We collected nationwide centralized drinking water sources data and serving population data covering 395 prefecture-level and county-level cities and water quality data in the two most populous provinces (Guangdong and Shandong) to examine their contribution and importance. Geographically, the drinking water source types can be classified into three clear regions exhibiting apparent differences in the respective contributions of rivers, lakes and reservoirs, and groundwater. We further found that overall, lakes and reservoirs account for 40.6% of the centralized drinking water sources vs. river (30.8%) and groundwater (28.6%) in China. Lakes and reservoirs are particularly important in the densely populated eastern region, where they are used as drinking water sources by 51.0% of the population (318 million). Moreover, the contribution to the drinking water supply from lakes and reservoirs is increasing due to their better water quality and many cross-regional water transfer projects. These results will be useful for the government to improve and optimize the establishment of centralized drinking water sources, which provide safe and clean drinking water in China to safeguard people's lives and health and realize sustainable development goals.

Driven by the minimization of total energy, the multi-domain morphology is preferred in as-grown ferroelectrics to reduce the depolarization and strain energy during the paraelectric to ferroelectric phase transition. However, the complicated multi-domain is not desirable for certain high-performance ferroelectric electro-optic devices. In this work, we achieve a reproducible and stable large-area monodomain in as-grown bulk ferroelectric single crystal [Formula: see text]. The monodomain dominates the entire single crystal, which is attributed to the internal charge carriers from the photoexcited disproportionation reaction of Sn ions. The charge carriers effectively screen the depolarization field and therefore decrease the depolarization energy and facilitate the formation of monodomain. This work offers a potential approach for engineering bulk ferroelectrics with a stable monodomain, which is desirable for the high-performance ferroelectric electro-optic devices.

Determining response patterns of plant leaf elements to environmental variables would be beneficial in understanding plant adaptive strategies and in predicting ecosystem biogeochemistry processes. Despite the vital role of microelements in life chemistry and ecosystem functioning, little is known about how plant microelement concentrations, especially their bioconcentration factors (BCFs, the ratio of plant to soil concentration of elements), respond to large-scale environmental gradients, such as aridity, soil properties and anthropogenic activities, in drylands. The aim of the present study was to fill this important gap. We determined leaf microelement BCFs by measuring the concentrations of Mn, Fe, Ni, Cu and Zn in soils from 33 sites and leaves of 111 plants from 67 species across the drylands of China. Leaf microelement concentrations were maintained within normal ranges to satisfy the basic requirements of plants, even in nutrient-poor soil. Aridity, soil organic carbon (SOC) and electrical conductivity (EC) had positive effects, while soil pH had a negative effect on leaf microelement concentrations. Except for Fe, aridity affected leaf microelement BCFs negatively and indirectly by increasing soil pH and SOC. Anthropogenic activities and soil clay contents had relatively weak impacts on both leaf microelement concentrations and BCFs. Moreover, leaf microelement concentrations and BCFs shifted with thresholds at 0.89 for aridity and 7.9 and 8.9 for soil pH. Woody plants were positive indicator species and herbaceous plants were mainly negative indicator species of leaf microelement concentrations and BCFs for aridity and soil pH. Our results suggest that increased aridity limits the absorption of microelements by plant leaves and enhances leaf microelement concentrations. The identification of indicator species for the response of plant microelements to aridity and key soil characteristics revealed that woody species in drylands were more tolerant to environmental changes than herbaceous species.

In eutrophic lakes, even if external loading is controlled, internal nutrient loading delays the recovery of lake eutrophication. When the input of external pollutants is reduced, the dissolved oxygen environment at the sediment interface improves in a season without algal blooms. As an important part of lake ecosystems, macroinvertebrates are sensitive to hypoxia caused by eutrophication; however, how this change affects macroinvertebrates is still unknown. In this study, we analysed the monitoring data of northern Lake Taihu from 2007 to 2019. After 2007, the external loading of Lake Taihu was relatively stable, but eutrophication began to intensify after 2013, and the nutrients in the sediments also began to decline, which was related to the efficient use of nutrients by algal blooms. The community structure and population density of macroinvertebrates showed different responses in different stages. In particular, the density of oligochaetes and the Shannon–Wiener index showed significant differences in their response to different stages, and their sensitivity to eutrophication was significantly reduced. Under eutrophication conditions dominated by internal loading, frequent hypoxia occurs at the sediment interface only when an algal bloom erupts. When there is no bloom, the probability of sediment hypoxia is significantly reduced under the disturbance of wind. Our results indicate that the current method for evaluating lake eutrophication based on oligochaetes and the Shannon–Wiener diversity index may lose its sensitivity.

Developing a single-phase self-rectifying memristor is desirable and functionally adaptive to dynamic environmental stimuli variations. Here, the authors report a single phase CuInP2S6 based memristor with continuously tunable current rectifying.

In this study, to optimize the Staphylococcus aureus control program, a meta-analysis was conducted to investigate the epidemiology and antimicrobial resistance (AMR) profile of S. aureus-associated bovine mastitis in China from 2000 to 2020. A total of 33 publications from PubMed, Google Scholar, and China National Knowledge Infrastructure (CNKI) database were included in our research, among which nine publications included the AMR test. The pooled prevalence of S. aureus was 36.23%, and subgroup analysis revealed that the prevalence dropped from 2000–2010 to 2011–2020, which shows that China is on the right track. The pooled AMR rate indicate isolates were most resistant to β-lactams (50.68%), followed by quinolones (36.23%), macrolides (34.08%), sulfonamides (32.25%), tetracyclines (27.83%), aminoglycosides (26.44%), lincosamides (23.39%), and amphenicol (10.33%). Both the pooled prevalence and AMR of S. aureus in China are higher than those in Western countries, such as Germany, Belgium, Ireland, and the United States—countries with a long animal husbandry history and good management. Thus, there is still room to improve the treatment of S. aureus-associated bovine mastitis in China.

Biodiversity-ecosystem functioning relationships may vary with climate. Here, the authors study relationships of plant and soil microbial diversity with soil nutrient multifunctionality in 130 dryland sites in China, finding a shift towards greater importance of soil microbial diversity in arid conditions.

Study region: The Nanliu River Basin in Beibu Gulf, China. Study focus: The variations in water discharge and sediment load were analysed for 1961–2015. In addition, sediment retention by high-density small water conservancy facilities in the tributaries was estimated by a hydrological model with different scenarios. At the end of the study, the variation in the relationship between water discharge and suspended sediment concentration (SSC) and the impact on riverbeds were analysed. New hydrological insights for the region: The sediment load showed a dramatically decreasing trend, and an abrupt change point in 1988 was detected by a Mann–Kendall test. Compared to the baseline period (1961–1988), the sediment load in the altered period (1989–2015) decreased by 41.7%. By employing the SWAT model with different scenarios, sediment retention by high-density small water conservancy facilities in the tributaries was estimated in the basin, with a mean value of 457.1 × 103 tons/yr during the altered period. The construction of water conservancy facilities has been the key driver of the significant reduction in sediment load observed in the Nanliu River. The rating curves of monthly SSC–discharge showed clockwise patterns, which were different from the Yangtze River’s counter-clockwise pattern. SSC reductions and excessive sand mining in the main channel have strongly affected riverbeds, leading to a year-by-year drop.

It is commonly believed that climate plays an important role in shaping the patterns of plant species richness. However, it remains unclear how climate may affect plant richness across large spatial scales and also over long-terms, for example across massive arid regions during the Quaternary and into the future. To fill this knowledge gap, we examined the long-term trends in plant species richness across vast drylands in China based on our newly developed climate-species richness models. We first generated optimal random forest models based on the relationships between the current (CUR, 1970–2000) annual, perennial, woody and total species richness and climatic variables. We subsequently hindcasted and forecasted plant species richness in five other periods: last interglacial (LIG, 120,000–140,000 years BP), last glacial maximum (LGM, about 22,000 years BP), mid-Holocene (MH, about 6000 years BP), 2041–2060 (2050), and 2061–2080 (2070). Our results showed that total and herbaceous species richness exhibited similar patterns that were driven by temperature and precipitation. Both groups of species formed a transition zone between arid and semi-arid regions in all periods except LIG. In contrast, woody species richness did not form any transition zone because it was regulated mainly by temperature. Furthermore, the mean richness of herbaceous, woody and all species exhibited gradually increasing trends from LIG to 2070 across drylands in China. On the one hand, herbaceous species were much more sensitive to climate change than woody species. On the other hand, plant species richness in mountain-basin systems and Taklamakan Desert regions were more sensitive to climate change than in meadows and steppes. These results shed new insights into the past and future changes in plant species richness over vast drylands and provide valuable information for future conservation efforts under global warming.

Microbial communities normally comprise a few core species and large numbers of satellite species. These two sub-communities have different ecological and functional roles in natural environments, but knowledge on the assembly processes and co-occurrence patterns of the core and satellite species in Tibetan lakes is still sparse. Here, we investigated the ecological processes and co-occurrence relationships of the core and satellite bacterial sub-communities in the Tibetan lakes via 454 sequencing of 16S rRNA gene. Our studies indicated that the core and satellite bacterial sub-communities have similar dominant phyla (Proteobacteria, Bacteroidetes, and Actinobacteria). But the core sub-communities were less diverse and exhibited a stronger distance-decay relationship than the satellite sub-communities. In addition, topological properties of nodes in the network demonstrated that the core sub-communities had more complex and stable co-occurrence associations and were primarily driven by stochastic processes (58.19%). By contrast, the satellite sub-communities were mainly governed by deterministic processes (62.17%). Overall, this study demonstrated the differences in the core and satellite sub-community assembly and network stability, suggesting the importance of considering species traits to understand the biogeographic distribution of bacterial communities in high-altitude lakes.

Drylands are expected to be affected by greater global drought variability in the future; consequently, how dryland ecosystems respond to drought events needs urgent attention. In this study, the Normalized Vegetation Index (NDVI) and Standardized Precipitation and Evaporation Index (SPEI) were employed to quantify the resistance of ecosystem productivity to drought events in drylands of northern China between 1982 and 2015. The relationships and temporal trends of resistance and drought characteristics, which included length, severity, and interval, were examined. The temporal trends of resistance responded greatest to those of drought length, and drought length was the most sensitive and had the strongest negative effect with respect to resistance. Resistance decreased with increasing drought length and did not recover with decreasing drought length in hyper-arid regions after 2004, but did recover in arid and semi-arid regions from 2004 and in dry sub-humid regions from 1997. We reason that the regional differences in resistance may result from the seed bank and compensatory effects of plant species under drought events. In particular, this study implies that the ecosystem productivity of hyper-arid regions is the most vulnerable to drought events, and the drought–resistance and drought–recovery interactions are likely to respond abnormally or even shift under ongoing drought change.

Plants need water and energy for their growth and reproduction. However, how water and energy availability influence dryland plant diversity along the aridity gradient in water-limited regions is still lacking. Hence, quantitative analyses were conducted to evaluate the relative importance of water and energy to dryland plant diversity based on 1039 quadrats across 184 sites in China’s dryland. The results indicated that water availability and the water–energy interaction were pivotal to plant diversity in the entire dryland and consistent with the predictions of the water–energy dynamic hypothesis. The predominance of water limitation on dryland plant diversity showed a weak trend with decreasing aridity, while the effects of energy on plants were found to be significant in mesic regions. Moreover, the responses of different plant lifeforms to water and energy were found to vary along the aridity gradient. In conclusion, the study will enrich the limited knowledge about the effects of water and energy on plant diversity (overall plants and different lifeforms) in the dryland of China along the aridity gradient.

Convergence is commonly caused by environmental filtering, severe climatic conditions and local disturbance. The basic aim of the present study was to understand the pattern of leaf traits across diverse desert plant species in a common garden, in addition to determining the effect of plant life forms (PLF), such as herb, shrub and subshrub, phylogeny and soil properties on leaf traits. Six leaf traits, namely carbon (C), nitrogen (N), phosphorus (P), potassium (K), δ13C and leaf water potential (LWP) of 37 dominant desert plant species were investigated and analyzed. The C, N, K and δ13C concentrations in leaves of shrubs were found higher than herbs and subshrubs; however, P and LWP levels were higher in the leaves of subshrubs following herbs and shrubs. Moreover, leaf C showed a significant positive correlation with N and a negative correlation with δ13C. Leaf N exhibited a positive correlation with P. The relationship between soil and plant macro-elements was found generally insignificant but soil C and N exhibited a significant positive correlation with leaf P. Taxonomy showed a stronger effect on leaf C, N, P and δ13C than soil properties, explaining >50% of the total variability. C3 plants showed higher leaf C, N, P, K and LWP concentration than C4 plants, whereas C4 plants had higher δ13C than C3 plants. Legumes exhibited higher leaf C, N, K and LWP than nonlegumes, while nonlegumes had higher P and δ13C concentration than legumes. In all the species, significant phylogenetic signals (PS) were detected for C and N and nonsignificant PS for the rest of the leaf traits. In addition, these phylogenetic signals were found lower (K-value < 1), and the maximum K-value was noted for C (K = 0.35). The plants of common garden evolved and adapted themselves for their survival in the arid environment and showed convergent variations in their leaf traits. However, these variations were not phylogenetics-specific. Furthermore, marks of convergence found in leaf traits of the study area were most likely due to the environmental factors.

Lake Taihu is a large shallow eutrophic lake with frequent recurrence of cyanobacterial bloom which has high variable distribution in space and time. Based on the field observations and remote sensing monitoring of cyanobacterial bloom occurrence, in conjunction with laboratory controlled experiments of mixing effects on large colony formation and colonies upward moving velocity measurements, it is found that the small or moderate wind-induced disturbance would increase the colonies size and enable it more easily to overcome the mixing and float to water surface rapidly during post-disturbance. The proposed mechanism of wind induced mixing on cyanobacterial colony enlargement is associated with the presence of the extracellular polysaccharide (EPS) which increased the size and buoyancy of cyanobacteria colonies and promote the colonies aggregate at the water surface to form bloom. Both the vertical movement and horizontal migration of cyanobacterial colonies were controlled by the wind induced hydrodynamics. Because of the high variation of wind and current coupling with the large cyanobacterial colony formation make the bloom occurrence as highly mutable in space and time. This physical factor determining cyanobacterial bloom formation in the large shallow lake differ from the previously documented light-mediated bloom formation dynamics.

Many studies have focused on the interactive effects of temperature increases due to global warming and nutrient enrichment on phytoplankton communities. Recently, non-temperature effects of climate change (e.g., decreases in wind speed and increases in solar radiation) on large lakes have received increasing attention. To evaluate the relative contributions of both temperature and non-temperature effects on phytoplankton communities in a large eutrophic subtropical shallow lake, we analyzed long-term monitoring data from Lake Taihu, China from 1997 to 2016. Results showed that Lake Taihu's spring phytoplankton biovolume and composition changed dramatically over this time frame, with a change in dominant species. Stepwise multiple linear regression models indicated that spring phytoplankton biovolume was strongly influenced by total phosphorus (TP), light condition, wind speed and total nitrogen (TN) (radj2 = 0.8, p < 0.01). Partial redundancy analysis (pRDA) showed that light condition accounted for the greatest variation of phytoplankton community composition, followed by TP and wind speed, as well as the interactions between TP and wind speed. Our study points to the additional importance of non-temperature effects of climate change on phytoplankton community dynamics in Lake Taihu.

Developing new ornamental cultivars with improved floral attributes is a major goal in floriculture. Biotechnological approach together with classical breeding methods has been used to modify floral color, appearance as well as for increasing disease resistance. Transgenic strategies possess immense potential to produce novel flower phenotypes that are not found in nature. Adoption of Genetic engineering has supported the idea of floral trait modification. Ornamental plant attributes like floral color, fragrance, disease resistance, and vase life can be improved by means of genetic manipulation. Therefore, we witness transgenic plant varieties of high aesthetic and commercial value. This review focuses on biotechnological advancements in manipulating key floral traits that contribute in development of diverse ornamental plant lines. Data clearly reveals that regulation of biosynthetic pathways related to characteristics like pigment production, flower morphology and fragrance is both possible and predictable. In spite of their great significance, small number of genetically engineered varieties of ornamental plants has been field tested. Today, novel flower colors production is regarded as chief commercial benefit obtained from transgenic plants. But certain other floral traits are much more important and have high commercial potential. Other than achievements such as novel architecture, modified flower color, etc., very few reports are available regarding successful transformation of other valuable horticultural characteristics. Our review also summarized biotechnological efforts related to enhancement of fragrance and induction of early flowering along with changes in floral anatomy and morphology.

Climate change has been studied for many decades. Growing scientific, political, and public attention has focused on climate change and its effect on ecosystems, including lake ecosystems. In this study, we conducted comparative quantitative and qualitative analyses that focused on research development, current hotspots, and potential future directions of climate change research associated with lakes using a bibliometric analysis based on the Science Citation Index (SCI) database. A total of 10,196 papers associated with climate change-lake research were published in 1,206 journals. Rapid development occurred over the past 25 years and the number of published papers considerably increased since the 2000s. A keyword analysis showed that among the top 50 most frequently used keywords, paleoecology, palynology, paleolimnology, climate change, and pollen analysis exhibited decreasing trends. Recently, eutrophication exhibited one of the highest co-occurrence frequencies with climate change. Keywords such as algae and cyanobacteria also showed increasing trends with climate change, implied that more attention was paid to the harmful cyanobacterial blooms. Another significant increasing trend was observed between climate change and remote sensing, which is a modern technology that is now widely used in limnology. Our results also indicate that a distinct turning point associated with climate change-lake research occurred between 1991 and 2015. Before the 2000s, most studies focused on paleolimnology. Specifically, researchers were searching for the evidence of climate change in lake sediments by using traditional technologies, such as reflecting ancient climate using the information recorded by diatom or pollen in the sediments. Recently, more studies have focused on modern limnology, e.g., the effects of climate change on lake ecosystems. In addition, future research may focus on the following topics: 1) the interactive effects of climate change and eutrophication, or other environmental variables, on lake ecosystems; 2) solutions for mitigating the negative effects of climate change; and 3) the potential effects of eutrophication on climate change.

CaCu3Ti4−xYxO12 (0≤x≤0.12) ceramics were fabricated with conventional solid-state reaction method. Phase structure and microstructure of prepared ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The impedance and modulus tests both suggested the existence of two different relaxation behavior, which were attributed to bulk and grain boundary response. In addition, the conductivity and dielectric permittivity showed a step-like behavior under 405K. Meanwhile, frequency independence of dc conduction became dominant when above 405K. In CCTO ceramic, rare earth element Y3+ ions as an acceptor were used to substitute Ti sites, decreasing the concentration of oxygen vacancy around grain-electrode and grain boundary. The reason to the reduction of dielectric behavior in low frequencies range was associated with the Y doping in CCTO ceramic.

A yearlong campaign to examine sediment resuspension was conducted in large, shallow and eutrophic Lake Taihu, China, to investigate the influence of vegetation on sediment resuspension and its nutrient effects. The study was conducted at 6 sites located in both phytoplankton-dominated zone and macrophyte-dominated zone of the lake, lasting for a total of 13 months, with collections made at two-week intervals. Sediment resuspension in Taihu, with a two-week high average rate of 1771 g·m(-2)·d(-1) and a yearly average rate of 377 g·m(-2)·d(-1), is much stronger than in many other lakes worldwide, as Taihu is quite shallow and contains a long fetch. The occurrence of macrophytes, however, provided quite strong abatement of sediment resuspension, which may reduce the sediment resuspension rate up to 29-fold. The contribution of nitrogen and phosphorus to the water column from sediment resuspension was estimated as 0.34 mg·L(-1) and 0.051 mg·L(-1) in the phytoplankton-dominated zone. Sediment resuspension also largely reduced transparency and then stimulated phytoplankton growth. Therefore, sediment resuspension may be one of the most important factors delaying the recovery of eutrophic Lake Taihu, and the influence of sediment resuspension on water quality must also be taken into account by the lake managers when they determine the restoration target.

We examined the potential effects of environmental variables, and their interaction, on phytoplankton community succession in spring using long-term data from 1992 to 2012 in Lake Taihu, China. Laboratory experiments were additionally performed to test the sensitivity of the phytoplankton community to nutrient concentrations and temperature. A phytoplankton community structure analysis from 1992 to 2012 showed that Cryptomonas (Cryptophyta) was the dominant genus in spring during the early 1990s. Dominance then shifted to Ulothrix (Chlorophyta) in 1996 and 1997. However, Cryptomonas again dominated in 1999, 2000, and 2002, with Ulothrix regaining dominance from 2003 to 2006. The bloom-forming cyanobacterial genus Microcystis dominated in 1995, 2001 and 2007-2012. The results of ordinations indicated that the nutrient concentration (as indicated by the trophic state index) was the most important factor affecting phytoplankton community succession during the past two decades. In the laboratory experiments, shifts in dominance among phytoplankton taxa occurred in all nutrient addition treatments. Results of both long term monitoring and experiment indicated that nutrients exert a stronger control than water temperature on phytoplankton communities during spring. Interactive effect of nutrients and water temperature was the next principal factor. Overall, phytoplankton community composition was mediated by nutrients concentrations, but this effect was strongly enhanced by elevated water temperatures.

Population topology of particle swarm optimization (PSO) will directly affect the dissemination of optimal information during the evolutionary process and will have a significant impact on the performance of PSO. Classic static population topologies are usually used in PSO, such as fully connected topology, ring topology, star topology, and square topology. In this paper, the performance of PSO with the proposed random topologies is analyzed, and the relationship between population topology and the performance of PSO is also explored from the perspective of graph theory characteristics in population topologies. Further, in a relatively new PSO variant which named logistic dynamic particle optimization, an extensive simulation study is presented to discuss the effectiveness of the random topology and the design strategies of population topology. Finally, the experimental data are analyzed and discussed. And about the design and use of population topology on PSO, some useful conclusions are proposed which can provide a basis for further discussion and research.