Explore the vast range of titles available.

The interactive effects of binary antibiotic mixtures of spiramycin (SP) and ampicillin (AMP) on Microcystis aeruginosa (MA) in terms of growth as well as microcystin production and extracellular release were investigated through the response surface methodology (RSM). SP with higher 50 and 5% effective concentrations in MA growth was more toxic to MA than AMP. RSM model for toxic unit approach suggested that the combined toxicity of SP and AMP varied from synergism to antagonism with SP/AMP mixture ratio decreasing from reversed equitoxic ratio (5:1) to equitoxic ratio (1:5). Deviations from the prediction of concentration addition (CA) and independent action (IA) model further indicated that combined toxicity of target antibiotics mixed in equivalent ratio (1:1) varied from synergism to antagonism with increasing total dose of SP and AMP. With the increase of SP/AMP mixture ratio, combined effect of mixed antibiotics on MA growth changed from stimulation to inhibition due to the variation of the combined toxicity and the increasing proportion of higher toxic component (SP) in the mixture. The mixture of target antibiotics at their environmentally relevant concentrations with increased total dose and SP/AMP mixture ratio stimulated intracellular microcystin synthesis and facilitated MA cell lysis, thus leading to the increase of microcystin productivity and extracellular release.

Biogeochemical cycling of nitrous oxide (N2O), a significant greenhouse gas (GHG), can influence global climate change. The production and emission of N2O mediated by hydrological regimes is particularly active in water level fluctuation zones (WLFZs). However, the hydrological mechanisms affecting N2O transformation and production across the water-sediment micro-interface remain unclear. In this study, intact sediment cores from the WLFZs of the Three Gorges Reservoir (TGR) were incubated for 24 days in a laboratory microcosm to identify the effects of the flooding-drying processes on the yield and emission of N2O. Results showed a source-sink transition of N2O in the first 1.5 days during the flooding period, with the water column subsequently acting as a sink relative to the atmosphere in the following experimental period. The source-sink transition was ascribed to changes in oxygen concentration in the water column and sediment regulation of NO3−-N transformation, resulting in denitrification and N2O production. Preliminary estimates on the mass budget of N2O in a typical WLFZs of the TGR showed slight emission fluxes, ranging from 13.08 to 43.08 μmol m−2 from flooding period to drying process. Although these N2O emissions were relatively low, the emission peak detected during the initial period (first 1.5 days) of the flooding phase provides important knowledge on the mitigation of GHG emissions from hydropower sources, which should be incorporated into future reservoir operations.

In eutrophic lake restorations, in situ capping is an often considered method to control sediment internal phosphorus (P) pollution for mitigating eutrophication status. Subsequent aquatic macrophyte revegetation can directly derive P from the sediment for growth. However, the effects of capping with clean soils on internal P release from sediments under rooted aquatic macrophyte revegetation are still unclear. In the present study, the influences of sediment P remobilization by P. australis revegetation on P inactivation by capping were investigated based on an entire growth simulation study. Our findings showed during the growth of P. australis, tests conducted on total phosphorous (TP), calcium-bound P (Ca-P), loosely bound P (loose-P), organic P (Org-P), and iron-adsorbed P (Fe-P) found significant changes (p < 0.001). Specifically, the mean contents of TP and Ca-P decreased by 291.1 and 224.2 mg kg−1, respectively, while those of Fe-P increased from 26.4 to 124.8 mg kg−1. In addition, sediment mobile-P contents increased coincidentally with the growth of P. australis during the whole course of experiment. Further analysis indicated calculated diffusion fluxes of soluble reactive phosphorus (SRP) generally increased with incubation time, although capping effectively induced the reduction of SRP concentration in pore water and its release to waters. Therefore, sediment P remobilization by P. australis revegetation was able to enhance P lability in lake sediments, with intermediate activation ability compared to other correlated water bodies. This phenomenon was most likely attributed to solubilization of sediment P by organic acids secreted from P. australis rhizosphere. Overall, sediment P remobilization by rooted macrophytes is unfavorable for capping to control internal P release to water column during eutrophic lake restorations.

This two-year study focused on mechanisms of nutrient removal efficiency and variation in this efficiency in a pilot-scale natural wetland with different macrophyte species. Effects of plant harvesting and the differences among plant species ( Ceratophyllum demersum , Nelumbo nucifera , Zizania latifolia , Hemarthria sibirica , Phragmites communis , and Typha orientalis ) were investigated. Results show that the mean retention of total nitrogen (N), total dissolved N, ammonia N, nitrite N, total phosphorus (P), total dissolved P, and phosphate P in the second year was generally lower than that found in the first year. Harvest of above-ground macrophytes had a beneficial effect on retention capacity, especially for total dissolved N and ammonia N, whereas an increase in nutrient concentration was observed in zones that were not harvested. The total N removal efficiency had a positive relationship with inflow loading. A mixture of Z. latifolia and T. orientalis demonstrated the best potential for both N and P retention.

The Marine Protected Area in Gilbert Bay, Labrador was created mainly to protect its resident Atlantic cod (Gadus morhua) population, which is genetically distinguishable from other northern Atlantic cod populations. In order to effectively manage this population in the future, basic information regarding production, ecosystem carrying capacity, and population dynamics is needed. In this research, a bottom-up food chain dynamics approach was used to calculate the resident fish production in Gilbert Bay (340 tons per year) and the ecosystem carrying capacity for Atlantic cod (286 tons) based on a primary production rate of 190 g C m-2 y-1. The availability of suitable habitat for juvenile cod as well as food availability may limit the production of Atlantic cod (109 tons per year). The age-structured Leslie matrix population model was used to simulate the rebuilding of the Atlantic cod population in Gilbert Bay. The elasticity analysis suggests that protecting juveniles and their habitat is most important to the population growth. Key words: Gilbert Bay, Marine Protected Area, Atlantic cod, fish production, ecosystem carrying capacity, Leslie matrix, population projection

In this paper, we used the same four-parameter function as Hathaway, Wilson, and Reichmann (1994) proposed and studied the temporal behavior of sunspot cycles 12-22. We used the monthly averages of sunspot areas and their 13-point smoothed data. Our results show the following. (1) The four-parameter function may reduce to a function of only two parameters. (2) As a cycle progresses, the two-parameter function can be accurately determined after 4-4.5 years from the start of the cycle. A good prediction can be made for the timing and size of the sunspot maximum and for the behavior of the remaining 5-10 years of the cycle. (3) The solar activity in the remaining and forthcoming years of cycle 23 is predicted. (4) The smoothed monthly sunspot areas are more suitable to be employed for prediction at the maximum and the descending period of a cycle, whereas at the early period of a cycle the (un-smoothed) monthly data are more suitable.

Early detection of autism spectrum disorder (ASD) is particularly important given its insidious qualities and the high cost of the diagnostic process. Currently, static functional connectivity studies have achieved significant results in the field of ASD detection. However, with the deepening of clinical research, more and more evidence suggests that dynamic functional connectivity analysis can more comprehensively reveal the complex and variable characteristics of brain networks and their underlying mechanisms, thus providing more solid scientific support for computer-aided diagnosis of ASD. To overcome the lack of time-scale information in static functional connectivity analysis, in this paper, we proposes an innovative GNN-LSTM model, which combines the advantages of long short-term memory (LSTM) and graph neural networks (GNNs). The model captures the spatial features in fMRI data by GNN and aggregates the temporal information of dynamic functional connectivity using LSTM to generate a more comprehensive spatio-temporal feature representation of fMRI data. Further, a dynamic graph pooling method is proposed to extract the final node representations from the dynamic graph representations for classification tasks. To address the variable dependence of dynamic feature connectivity on time scales, the model introduces a jump connection mechanism to enhance information extraction between internal units and capture features at different time scales. The model achieves remarkable results on the ABIDE dataset, with accuracies of 80.4% on the ABIDE I and 79.63% on the ABIDE II, which strongly demonstrates the effectiveness and potential of the model for ASD detection. This study not only provides new perspectives and methods for computer-aided diagnosis of ASD but also provides useful references for research in related fields.

Cropland is fundamental to food security, and monitoring cropland non-agriculturalization through satellite enforcement can effectively manage and protect cropland. However, existing research primarily focuses on optical imagery, and there are problems such as low data processing efficiency and long updating cycles, which make it difficult to meet the needs of large-scale rapid monitoring. To comprehensively and accurately obtain cropland change information, this paper proposes a method based on the Google Earth Engine (GEE) cloud platform, combining optical imagery and synthetic aperture radar (SAR) data for quick and accurate detection of cropland non-agriculturalization. The method uses existing land-use/land cover (LULC) products to quickly update cropland mapping, employs change vector analysis (CVA) for detecting non-agricultural changes in cropland, and introduces vegetation indices to remove pseudo-changes. Using Shanwei City, Guangdong Province, as a case study, the results show that (1) the cropland map generated in this study aligns well with the actual distribution of cropland, achieving an accuracy of 90.8%; (2) compared to using optical imagery alone, the combined optical and SAR data improves monitoring accuracy by 22.7%, with an overall accuracy of 73.65%; (3) in the past five years, cropland changes in Shanwei followed a pattern of an initial increase followed by a decrease. The research in this paper can provide technical reference for the rapid monitoring of cropland non-agriculturalization on a large scale, so as to promote cropland protection and rational utilization of cropland.

Intestinal microbiota is gaining increasing interest from researchers, and a series of studies proved that gut bacteria plays a significant role in various malignancies, especially in colorectal cancer (CRC). In this study, a cohort of 34 CRC patients (average age=65 years old), 26 young volunteers (below 30 years old), and 26 old volunteers (over 60 years old) was enrolled. 16S ribosomal RNA gene sequencing was used to explore fecal bacteria diversity. The operational taxonomic unit (OTU) clustering analysis and NMDS (non-metric multidimensional scaling) analysis were used to separate different groups. Cluster of ortholog genes (COG) functional annotation and Kyoto encyclopedia of genes and genomes (KEGG) were used to detect enriched pathways among three groups. Community separations were observed among the three groups of this cohort. Clostridia , Actinobacteria , Bifidobacterium , and Fusobacteria were the most enriched bacteria in the young group, old group, and CRC group respectively. Also, in the young, old, and CRC group, the ratio of Firmicutes/Bacteroidetes was increased sequentially despite no statistical differences. Further, COG showed that transcription, cell wall/membrane/envelope biogenesis, inorganic ion transport and metabolism, and signal transduction mechanisms were differentially expressed among three groups. KEGG pathways associated with ABC transporters, amino sugar and nucleotide sugar metabolism, arginine and proline metabolism, and aminoacyl-tRNA biosynthesis also showed statistical differences among the three groups. These results indicated that the intestinal bacterial community varied as age changed and was related to CRC, and we discussed that specific bacteria enriched in the young and old group may exert a protective function, while bacteria enriched in the CRC group may promote tumorigenesis.

Groundwater resources are crucial to socio-economic development and the ecosystem, and over-extraction can cause the groundwater level to drop, deplete reserves, and trigger geological hazards like land subsidence. The North China Plain (NCP) has experienced both subsidence and groundwater depletion due to over-extraction in the past 70 years. In this study, we used MT-InSAR technology and ascending C-band Sentinel-1 SAR data from 2017 to 2023 to study land deformation in the junction area of Shijiazhuang–Baoding–Cangzhou–Hengshui. We identified multiple subsidence funnels with a maximum rate exceeding −150 mm/year and a total deformation surpassing 600 mm. Seasonal decomposition methods accurately separated seasonal signals in the time-series deformation and groundwater level data. An exponential function model applied to long-term deformation showed no significant decrease in subsidence in severely affected areas. By modeling seasonal deformation and seasonal groundwater levels, we determined the elastic skeletal storage coefficients (Ske) to be in the range of 1.02 × 10−3~6.53 × 10−3 in subsidence areas. We obtained the spatiotemporal evolution of the total groundwater storage (TGWS), irreversible ground storage (IGWS), and recoverable ground storage (RGWS). The TGWS and IGWS decreased annually while the RGWS increased, which is attributable to the implementation of the South-to-North Water Diversion Project (SNWDP) and the issuance of groundwater withdrawal policies in the NCP.