Temporal Distribution Patterns Research Articles

Electric field simulation in the electrochemical machining of a thin-walled part cavity

The article is aimed at simulating an electric field in the interelectrode gap during the electrochemical machining of a thin-walled part cavity for aerospace equipment. The study involved simulating the process of electrochemical cavity machining at a constant voltage in a steady-state mode in the COMSOL Multiphysics environment. The simulation was carried out for the scheme of electrochemical machining with a movable cathode and vertical and horizontal feeding to the workpiece surface undergoing machining while maintaining a constant interelectrode gap. The following simulation conditions were adopted: 12Cr18Ni10Ti stainless steel as the material of the cathode tube; AlMg6 aluminum alloy as the material of the thin-walled part; NaNO3 solution as the electrolyte. When simulating the electric field in the interelectrode gap, the heat exchange process was taken into account. The simulation of the electric field in the electrochemical cavity machining of a thin-walled part yielded a macro that allows the process simulation to be adapted to different input process conditions. As a result of the simulation, the following distribution patterns were obtained: current density in the cathode, potentials, electric field in the interelectrode gap and adjacent area, and process temperature of electrochemical machining. The simulation results show that the electric field lines are directed toward the cathode from the workpiece periphery. This means that anodic dissolution of material occurs in a given region, which characterizes the law concerning the distribution of potentials in an electrochemical cell. The temperature distribution pattern obtained in the simulation revealed that a temperature increase in the machining zone is insignificant. An increase in electrolyte temperature is shown to result in a proportional increase in wall temperature. Thus, the conducted study provides a theoretical insight into the examined process.

A computational fluid dynamics (CFD) modeling in a new design of closed greenhouse

Closed greenhouses are crucial buildings for agriculture in controlled environments because they offer the best growing conditions for crops and shield them from outside influences. Researchers can now better optimize design parameters for increased crop output and energy efficiency by simulating airflow and temperature distribution inside closed greenhouses with the use of computational fluid dynamics (CFD) modeling. We examine the temperature distribution and airflow patterns inside the greenhouse under various environmental conditions using CFD simulations. Our findings show that, in comparison to traditional greenhouse constructions, the novel design greatly improves temperature uniformity and lowers energy use. Moreover, the greenhouse's thermal insulation design minimizes heat loss during the colder months, enhancing energy efficiency overall. We offer important insights into how design changes affect airflow dynamics and thermal performance in enclosed greenhouses by utilizing CFD modeling. Our research highlights how effective CFD modeling can be in maximizing crop yields and achieving sustainable agricultural practices through greenhouse design optimization. The integration of novel design components for improved energy efficiency and crop yield is a feasible outcome of this research, which advances the field of closed greenhouse technology overall. The research highlights the value of using CFD modeling to inform the design of next-generation closed greenhouse systems and has important ramifications for sustainable agriculture methods and greenhouse management techniques. The goals were to assess how well various heating/cooling systems maintained the ideal environmental conditions for plant growth. A verified CFD model was used to run the simulations, which took into account a number of variables including the shape of the greenhouse, the outside environment, and the interior heat sources. Important discoveries include understanding temperature gradients, airflow patterns, and possible areas for environmental management enhancement are presented in this paper. Results showed that the species mass transfer of vapor (H2o) will vary over time.

Heat of Hydration Analysis and Temperature Field Distribution Study for Super-Long Mass Concrete

In this study, the combination of ordinary cement concrete (OCC) and shrinkage-compensating concrete (SCC) was utilized to pour super-long mass concrete. The temperature and strain of the concrete were continuously monitored and managed actively after pouring. The investigation focused on the temporal and spatial distribution patterns of the temperature field, the temperature difference between the core and surface, and the strain evolution. Based on the constructed hydration exothermic model of layered poured concrete, the effects of the SCC, molding temperature, and surface heat transfer coefficient on the temperature field were analyzed. The results show that the temperature of super-long mass concrete rises quickly but falls slowly. SCC exhibits higher total hydration heat than OCC. The temperature field is symmetric along the length but asymmetric along the thickness due to varying efficiency of heat dissipation between the upper and lower parts of the concrete. After final setting of the concrete, the strain varies opposite to the temperature and peaks at −278 με. A few short cracks are observed on the end of the upper surface. Moreover, the numerical simulation results are in good agreement with the measured results. Increasing the molding temperature and surface wind speed increases the temperature difference between the core and surface. Conversely, increasing the thickness of the insulation layer is an effective way to curtail this difference. Thermal stress analysis is carried out and shows that lowering the molding temperature of SCC and increasing the thickness of insulation material can effectively reduce thermal stress.

Spatial and temporal patterns and driving factors of forest fires based on an optimal parameter-based geographic detector in the Panxi region, Southwest China

BackgroundThe Panxi region in China is among the areas that are most severely impacted by forest fires. Despite this, there is currently a lack of comprehensive and systematic research on the spatial and temporal distribution patterns, as well as the drivers, of forest fires in the region. To reveal bio-geo-climatic and anthropogenic influences, this study investigated the temporal and spatial characteristics of forest fires and migration patterns of the center of gravity of forest fires in Panxi. A parametric optimal geographical detection model was utilized to quantify the influence of various individual factors and their combinations on the spatial patterns of forest fire occurrence in the whole Panxi region and sub-region, by analyzing the forest fire dataset from 2004 to 2020.ResultsFrom 2004 to 2020, the Panxi region experienced an upward trend in the number of forest fires and the area burned. However, the trends were not consistent over the entire period. Between 2004 and 2014, both the number of fires and the area burned showed fluctuations and an overall increase. In contrast, between 2015 and 2020, there was a significant decrease in the number of fires, while the area burned showed a continued upward trend. The study identified abrupt changes in the frequency of forest fires and burned areas, primarily in 2007 and 2016. Spatially, forest fires in Panxi exhibited a positive correlation and local clustering. The river valley basin and hilly regions displayed a higher incidence of forest fires, which were concentrated mainly along the hill edges. In the whole area of Panxi, climatic factors have a predominant influence on forest fire occurrences. Specifically, evaporation, maximum temperature, average temperature, number of days without rain, and minimum temperature demonstrated the strongest explanatory power. Furthermore, this relationship was found to be reinforced when combined with topographical, human activities, and vegetation factors. The spatial variation of drought within each sub-district has a stronger explanatory power for the distribution characteristics of forest fires in the region than at the Panxi-wide scale. The factor with the maximum interaction in most regions was the dual factor of rainfall and drought.ConclusionsThe study’s findings validate the applicability of geographic probes for identifying the drivers of fire occurrence and enhance our understanding of the drivers and their combined effects on the spatial context of the fire-incident study area.

Chaotic turnover of rare and abundant species in a strongly interacting model community

The composition of ecological communities varies not only between different locations but also in time. Understanding the fundamental processes that drive species toward rarity or abundance is crucial to assessing ecosystem resilience and adaptation to changing environmental conditions. In plankton communities in particular, large temporal fluctuations in species abundances have been associated with chaotic dynamics. On the other hand, microbial diversity is overwhelmingly sustained by a "rare biosphere" of species with very low abundances. We consider here the possibility that interactions within a species-rich community can relate both phenomena. We use a Lotka-Volterra model with weak immigration and strong, disordered, and mostly competitive interactions between hundreds of species to bridge single-species temporal fluctuations and abundance distribution patterns. We highlight a generic chaotic regime where a few species at a time achieve dominance but are continuously overturned by the invasion of formerly rare species. We derive a focal-species model that captures the intermittent boom-and-bust dynamics that every species undergoes. Although species cannot be treated as effectively uncorrelated in their abundances, the community's effect on a focal species can nonetheless be described by a time-correlated noise characterized by a few effective parameters that can be estimated from time series. The model predicts a nonunitary exponent of the power-law abundance decay, which varies weakly with ecological parameters, consistent with observation in marine protist communities. The chaotic turnover regime is thus poised to capture relevant ecological features of species-rich microbial communities.

Extensive Genetic Diversity and Epidemiological Patterns of Factor H-Binding Protein Variants among Neisseria meningitidis in China.

Factor H-binding protein (fHbp) is a virulence factor expressed by Neisseria meningitidis (N. meningitidis), the primary causative agent of invasive meningococcal disease (IMD) in humans. fHbp is utilized as the main component in vaccines to provide protection against IMD caused by serogroup B N. meningitidis. In order to comprehensively investigate the genetic diversity and epidemiological patterns of fHbp variants within isolates of Chinese N. meningitidis, we utilized the NEIS0349 locus, which encompasses the complete coding sequences of fHbp. This enabled us to identify allelic variants of fHbp with enhanced resolution. A total of 109 fHbp variants were identified in 1013 Chinese N. meningitidis isolates. We reconstructed a phylogenetic tree and analyzed the epidemiological characteristics of each variant. Considering both temporal and geographical distribution patterns, only four fHbp variants (v2.16, v2.18, v2.404, and v2.21) exhibited persistent nationwide prevalence during the previous decade (2011-2021). These variants were highly prevalent in both serogroup B strains from patients and healthy individuals, suggesting their potential as suitable vaccine candidates for nationwide implementation against IMD caused by serogroup B strains. Our study emphasizes the significance of conducting continuous surveillance of meningococcal strains to monitor the genetic diversity of fHbp for the purpose of vaccine development.

Geospatial Insights into Aridity Conditions: MODIS Products and GIS Modeling in Northeast Brazil

Northeast Brazil (NEB), particularly its semiarid region, represents an area highly susceptible to the impacts of climate change, including severe droughts, and intense anthropogenic activities. These stresses may be accelerating environmental degradation and desertification of soil in NEB. The main aim of this study was to gain geospatial insights into the biophysical parameters of surface energy balance and actual evapotranspiration on a multi-temporal scale, aiming to detect and analyze the spectral behavioral patterns of areas vulnerable to degradation processes, based on thematic maps at the surface, for NEB and mainly the semiarid region of NEB from 2000 to 2019. Geospatial data from 8-day MODIS sensor products were used, such as surface reflectance (Terra/MOD09A1 and Aqua/MYD09A1), surface temperature (Terra/MOD11A2 and Aqua/MYD11A2), and actual evapotranspiration (Terra/MOD16A2 and Aqua/MYD16A2), version 6. Therefore, in this study, pixel-to-pixel values were processed by calculating the average pixel statistics for each year. From the reflectance product, digital processing of the surface albedo and spectral vegetation indices was also carried out, using computational programming scripts and machine learning algorithms developed via the Google Earth Engine (GEE) platform. The study also presents a seasonal analysis of these components and their relationships over 20 years. Through vegetation indices and statistical correlations, a new predictive model of actual evapotranspiration was developed. The quantitative and spatiotemporal spectral patterns of the parameters were assessed through descriptive statistics, measures of central tendency and dispersion, and statistical error analyses and correlation indices. Thematic maps highlighted the pixel-to-pixel results, with patterns of high temperature distribution mainly in the central and northeastern part of NEB and the semiarid region of NEB, highlighting the formation of persistent heat islands over time. Meanwhile, in these areas, the maps of actual evapotranspiration showed a drastic reduction due to the lesser availability of energy. Over time, the semiarid region of NEB presented areas with little and/or no vegetation cover, which were highly well-defined between the years 2012 and 2019, confirming that these areas are extremely vulnerable to degradation and desertification processes due to significant loss of vegetative and water resilience. The components of energy balance were highly interconnected to climatological and environmental conditions, showing the severe results of drought and accentuation of the water deficit in NEB, presenting a greater condition of aridity in the semiarid region of NEB over time.

Spatial–temporal distribution patterns and influencing factors analysis of comorbidity prevalence of chronic diseases among middle-aged and elderly people in China: focusing on exposure to ambient fine particulate matter (PM2.5)

ObjectiveThis study describes regional differences and dynamic changes in the prevalence of comorbidities among middle-aged and elderly people with chronic diseases (PCMC) in China from 2011–2018, and explores distribution patterns and the relationship between PM2.5 and PCMC, aiming to provide data support for regional prevention and control measures for chronic disease comorbidities in China.MethodsThis study utilized CHARLS follow-up data for ≥ 45-year-old individuals from 2011, 2013, 2015, and 2018 as research subjects. Missing values were filled using the random forest machine learning method. PCMC spatial clustering investigated using spatial autocorrelation methods. The relationship between macro factors and PCMC was examined using Geographically and Temporally Weighted Regression, Ordinary Linear Regression, and Geographically Weighted Regression.ResultsPCMC in China showing a decreasing trend. Hotspots of PCMC appeared mainly in western and northern provinces, while cold spots were in southeastern coastal provinces. PM2.5 content was a risk factor for PCMC, the range of influence expanded from the southeastern coastal areas to inland areas, and the magnitude of influence decreased from the southeastern coastal areas to inland areas.ConclusionPM2.5 content, as a risk factor, should be given special attention, taking into account regional factors. In the future, policy-makers should develop stricter air pollution control policies based on different regional economic, demographic, and geographic factors, while promoting public education, increasing public transportation, and urban green coverage.

Research on Flare Burner for Venting in Gas Transmission Station

With the widespread application of natural gas, the venting of remaining natural gas is an issue that cannot be ignored. Direct venting causes serious environmental pollution, so thermal venting, also known as combustion venting, has become an important way to solve environmental pollution problems. This simulation first established two different types of burners, cluster and array, to quantitatively analyze the flame combustion characteristics. It simulated the distribution patterns of velocity, temperature, and key component concentrations of the two burners under the same number of holes and fuel flow rate. The research results indicate that due to the existence of oblique jet flow in the converging and array types, a reflux zone is formed at the outlet of the diffuser, and natural gas and air are mixed more thoroughly, resulting in a more stable flame. By comparing the burnout rate and combustion failure rate of the two types of burners, it was found that the convergent flame height and residual natural gas content during combustion were the lowest, resulting in better combustion efficiency. On this basis, while ensuring the same flow rate, the number of converging combustion holes was increased, the model parameters were improved, and it was found that the flame height was further reduced. At the same time, while maintaining the combustion removal rate, the burnout rate was improved. The development of the above-mentioned flare burner is of great significance in improving combustion efficiency, reducing flame height, and reducing environmental pollution caused by venting.

Study on the Thermal Field of a Hydro-Generator under the Effect of a Plateau Climate

With the advancement in the developmental project on the lower reaches of the Yarlung Tsangpo River, the influence of the plateau climate environment on the performance of a hydro-generator has received more and more attention from researchers. This study numerically simulated the thermal field of a hydro-generator with a 20 MW capacity under the effect of a plateau climate. Ambient pressure and temperature are two main factors that affect the temperature distribution of the generator. In addition, temperature distributions with different speeds are also studied under a plateau climate. The results show that the generator temperature decreases with increasing air pressure and speed. The generator temperature increases linearly with increasing ambient temperature. Among them, when the pressure lies in the range of 25–85 kPa, the temperature change gradient of the stator structure is very large. The temperature difference gradually decreases with the increase in air pressure. The temperature gradient gradually slows down when the air pressure is above 85 kPa. When the pressure is located at 55–85 kPa, the average temperature difference of the stator windings is 6.325 °C, and the average temperature difference of the stator core is 3.815 °C. Finally, the temperature distribution pattern can provide a basis for staff in different barometric pressure regions. It can also improve the safety and reliability of the hydro-generator under the effect of a plateau climate, which is important for improving its integrated hydraulic performance.

The spatial and temporal characteristics of urban public safety under the residents' complaints: Evidence from 12345 data in Beijing, China

Accurately revealing the temporal and spatial laws of urban public safety incidents can provide a scientific basis for the construction of urban public safety. Telephone complaints are an important way for residents to perceive urban public safety based on objective reality. This paper uses the 12,345 citizen complaint hotline data in Beijing to explore the temporal and spatial distribution patterns and aggregation characteristics of urban public safety within a day by Emerging HotSpot Analysis. And analyzes the safety space classification based on the characteristic patterns. The results show that: ①The curve of complaints about urban public safety incidents in Beijing is obvious “double peaks” characteristics within one day, at 10:00 a.m. and 3:00 p.m. respectively; ②The occurrence of urban public safety incidents occurs from scratch, from small to large, from large to small, and gradually disappearing within one day; ③The complaints of urban public safety show significant aggregation characteristics in each time period, and the degree of aggregation changes with time; ④ The main manifestations are scattered hot spots and oscillating hot spots. The research conclusions are expected to provide new ideas for urban public safety research and enrich social perception research based on complaint data.

Synergistic effect of combating air pollutants and carbon emissions in the Yangtze River Delta of China: spatial and temporal divergence analysis and key influencing factors.

Synergizing the reduction of air pollutants and carbon emissions (APCE) has become a critical tactic alternative to address the issue of climate change. Taking the Yangtze River Delta (YRD) region of China as a case study, this paper explores the spatial and temporal distribution pattern of the coupling coordination degree (CCD) of combating APCE from 2011 to 2022, analyzes the dynamic change in CCD using the convergence test, and investigates the key factors affecting CCD via the Tobit regression model. The results show that (1) from 2011 to 2022, the air pollutants (AP) and CO2 emission (CE) in the YRD region decrease at the annual rate of 10.32% and 0.85%, respectively; (2) the CCD of reducing APCE in the YRD presents a W-shaped fluctuation before 2016 and then steps into a steady increase status after 2016; (3) the order of CCD in four provincial-level units by 2022 is Shanghai > Zhejiang > Jiangsu > Anhui. The proportion of cities where the CCD of reducing APCE enters the high-coordination period has reached 87.8%; and (4) the Tobit regression results affirm that economic growth, industrial structure, and green technological innovation exacerbate the CCD of combating APCE, while opening-up level mitigates it. The findings offer policymakers valuable insights into the importance of pursuing collaborative governance over APCE and ensuring sustainable development.

Study of spatial temperature features of road tunnel fires under multiple factors

AbstractAfter a highway tunnel fire, the rapid change of the internal ambient temperature directly affects the personal safety of pedestrians. Based mainly on the lateral possibility of fire location and considering the coupling effect of multiple factors in a two‐lane highway tunnel, this study systematically carried out 63 full‐size tunnel fire simulation studies relying on Fluent software. The smoke temperature distribution patterns in the transverse and longitudinal spaces of the tunnel after the fire were revealed. This study shows that the smoke temperature below the tunnel vault is susceptible to the effect of sidewall restraint, making the maximum temperature of the tunnel vault of the offset fire source large; considering the lateral location of the fire source, the maximum temperature prediction formula of the tunnel vault is modified to expose the change law of the longitudinal temperature decay of the vault. This paper reveals for the first time the law of temperature distribution changes at the characteristic height of the human eye on the evacuation platform in the tunnel; the systematic study of the fire source cross‐sectional temperature distribution changes at the key lining structure points, and it is found that a low‐temperature space conducive to personnel escape exists in the lower part of the tunnel away from the fire source side. The results of the study are beneficial to the design of safe evacuation paths in the tunnel and the active emergency evacuation of personnel in the near‐fire source area.

Mechanism of crack formation in corn during microwave drying process

AbstractBackground and ObjectivesDuring microwave drying process of corn, temperature and moisture content are the main reasons for crack formation, which reduces the drying quality. Therefore, it is necessary to study the effects of temperature and moisture content on crack generation.FindingsUnder the set drying conditions, as the temperature increases, cracks gradually increase, deformation gradually increases, and the crack index increases exponentially. As the moisture content decreases, deformation first increases and then decreases, single cracks first increase and then decrease and then increase, double cracks gradually decrease, multiple cracks continue to increase, and the crack index increases linearly. The deformation reaches its maximum value at a moisture content of 31%.ConclusionsThe results indicate that the generation of cracks is mainly influenced by water content. The maximum errors between the simulated and experimental values of temperature and moisture content are 4.73% and 7.76%, respectively, indicating that the model can be used to study the distribution patterns of temperature, moisture content, and deformation during corn drying.Significance and NoveltyThis study established a mathematical model for electromagnetic, mass, energy, and deformation of corn, coupled the model for the solution, and conducted experimental verification. The relationship between the generation of cracks during microwave drying of corn kernels and temperature and moisture content was revealed.

Policy implications for synergistic management of PM2.5 and O3 pollution from a pattern-process-sustainability perspective in China

In recent years, the pattern of air pollution in China has changed profoundly, and PM2.5 and surface ozone (O3) have become the main air pollutants affecting the air quality of cities and regions in China. The synergistic control of the two has become the key to the sustainable improvement of air quality in China. In this study, we investigated and analyzed the spatial and temporal distribution patterns, exposure health risks, key drivers, and sustainable characteristics of PM2.5 and O3 concentrations in China from 2013 to 2022 at the national and city cluster scales by combining methodological models such as spatial statistics, trend analysis, exposure-response function, Hurst index, and multi-scale geographically weighted regression (MGWR) model. Ultimately, a synergistic management system for PM2.5 and O3 pollution was proposed. The results showed that: (1) The PM2.5 concentration decreased at a rate of 1.45 μg/m3 per year (p < 0.05), while the O3 concentration increased at a rate of 2.54 μg/m3 per year (p < 0.05). The trends of the two concentrations showed significant differences in spatial distribution. (2) Population exposure risks to pollutants showed an increasing trend, with PM2.5 and O3 increasing by 55.1 % and 42.7 %, respectively. The annual deaths associated with exposure to PM2.5 and O3 demonstrated a decreasing and inverted U-shaped trend, respectively, with annual average deaths of 1.312 million and 98,000. Significant regional disparities in health risks from these pollutants were influenced by socio-economic factors such as industrial activities and population density. In the future, it is expected that more than half of China's regions will be exposed to rising risks of PM2.5 and O3 population exposure. (3) Key drivers of regional exacerbation in PM2.5 and O3 levels include the number of industrial enterprises above designated size (NSIE) and population agglomeration (PA), while the disposable income of urban residents (URDI), technological innovation (TI), and government attention level (GAL) emerged as primary factors in controlling pollution hotspots, ranked in order of influence from greatest to least as TI > GAL > URDI. Overall, this study sheds light on the current status of air pollution and health risk sustainability in China and enhances the understanding of future air pollution dynamics in China. The results of the study may help to develop effective targeted control measures to synergize the management of PM2.5 and O3 in different regions.

Research on Temporal and Spatial Distribution Pattern of the Night-Time Economy Supported by Multi-Source Data—A Case Study of Xiamen City, Fujian Province, China

The increasing proportion of night consumption in the total daily consumption means the night economy has become an indispensable part of national economic development. However, early social science research on alcohol in the night economy and social science research on the night leisure industry dominated our understanding of the night city. Few researchers have built effective mathematical statistical models to explore the spatio-temporal distribution and regional interactions of the night economy. This paper presents a method to analyze the spatial and temporal distribution pattern of the night economy based on multi-source data. Firstly, K-Means++ and DBSCAN were used to cluster OD points to identify the gathering areas of night activities. Then, the local L-function in “flow space” was used to extract the aggregated flow of each aggregation area and analyze the regional interactions. Finally, the correlation between night activity and night service facilities was calculated by using geographic detector, and night activity and lighting were coupled by the profit and loss value. The research shows that this method can identify the main areas of night activity, dig out the interrelationships at the community level, and find the new night activity gathering points and night economic growth areas in the future. This study extends the current situation that the night economy is limited to theoretical research and research in central urban areas, provides the temporal and spatial distribution of night activities and night lighting supplies from the perspective of big data, and provides a basis for future night economy research, urban planning, and relevant policy issuance.

Study of changes in temporal distribution pattern of rainfall at Dapoli station in Konkan region of Maharashtra

Dapoli situated in the Konkan region of Maharashtra is having average annual rainfall of 3587 mm with average number of rainy days 75. The yield of major Kharif season crop rice is affected by the erratic behavior of rainfall. Present study is an attempt to study the rainfall variations at the Dapoli station which will be useful for forecasting the future temporal availability of water. Comprehensive statistical tools were used to investigate trends in averages and monthly rainfall over the station on decadal basis. Forty years (year 1972-2011) daily rainfall data for Dapoli station was used for the analysis. Results of study showed that, decadal mean rainfall depths of June and August were found decreasing and those for September was found increasing. Mean rainfall depth variations for July as well as annual total rainfall were found random. Seven years moving averages showed that, rainfall depths for the months of June, July and August were found decreasing and for month of September was found increasing. In annual rainfall graph a slight decline was observed.

Temporal Distribution Patterns of Cryptic Brachionus calyciflorus (Rotifera) Species in Relation to Biogeographical Gradient Associated with Latitude.

Sympatric distribution and temporal overlap of cryptic zooplankton species pose a challenge to the framework of the niche differentiation theory and the mechanisms allowing competitor coexistence. We applied the methods of phylogenetic analysis, DNA taxonomy, and statistical analysis to study the temporal distribution patterns of the cryptic B. calyciflorus species, an excellent model, in three lakes, and to explore the putative mechanisms for their seasonal succession and temporal overlap. The results showed that in the warm-temperate Lake Yunlong, B. fernandoi and B. calyciflorus s.s. underwent a seasonal succession, which was largely attributed to their differential adaptation to water temperature. In the subtropical Lake Jinghu, B. fernandoi, B. calyciflorus s.s., and B. dorcas exhibited both seasonal succession and temporal overlap. Seasonal successions were largely attributed to their differential adaptation to temperature, and temporal overlap resulted from their differential responses to algal food concentration. In the tropical Lake Jinniu, B. calyciflorus s.s. persisted throughout the year and overlapped with B. dorcas for 5 months. The temporal overlap resulted from their differential responses to copepod predation. These results indicated that the temporal distribution pattern of the cryptic B. calyciforus species and the mechanism that allows competitor coexistence vary with different climate zones.

Contribution of circulating monocytes in maintaining homeostasis of resident macrophages in postnatal and young adult mouse cochlea

The percentage of macrophage subpopulations based on their origins in the adult cochlea remains unclear. This study aimed to elucidate the origins of cochlear macrophages during the onset phase and development of auditory function. We used three types of mice: wildtype ICR mice, colony-stimulating factor 1 receptor (Csf1r)-deficient mice, and Ms4a3Cre-Rosa tdTomato (Ms4a3tdT) transgenic mice. Macrophages were labeled with ionized calcium-binding adapter molecule 1 (Iba1), which is specific to more mature macrophages, and CD11b, which is specific to monocyte lineage. We investigated the spatial and temporal distribution patterns of resident macrophages in the cochlea during the postnatal and early adult stages. During the adult stages, the rate of monocytes recruited from the systemic circulation increased; moreover, Iba1+/CD11b− cochlear macrophages gradually decreased with age. Fate mapping of monocytes using Ms4a3tdT transgenic mice revealed an increased proportion of bone marrow-derived cochlear macrophages in the adult stage. Contrastingly, the proportion of yolk sac- and fetal liver-derived tissue-resident macrophages decreased steadily with age. This heterogeneity could be attributed to differences in environmental niches within the tissue or at the sub-tissue levels. Future studies should investigate the role of cochlear macrophages in homeostasis, inflammation, and other diseases, including infection, autoimmune, and metabolic diseases.

Microplastic Contamination in Sediments of Xiamen Bay: Investigating Ecological Consequences

Microplastic contamination in aquatic ecosystems poses a global environmental challenge, with local variations requiring focused investigations. This study examines the prevalence, characteristics, and ecological implications of microplastics in Xiamen Bay sediments, providing insights into the potential risks for both the environment and human health. The analysis encompasses spatial and temporal distribution patterns, ecological impacts on sediment biota, and pathways of human exposure. Key considerations for human health risk assessment are identified, considering particle characteristics, exposure levels, and vulnerable populations. The study concludes by emphasizing the importance of interdisciplinary collaboration in addressing these challenges and proposes strategies for mitigating the impact of microplastic contamination in Xiamen Bay.