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Conventional software frame synchronization methods are inefficient in processing huge continuous data without synchronization words. To improve the processing speed, a real-time synchronization algorithm is proposed based on reverse searching. Satellite data are grouped and searched in the reverse direction to avoid searching for synchronization words in huge continuous invalid data; thus, the frame synchronization speed is improved enormously. The fastest processing speed is up to 15445.9 Mbps when HJ-1C data are tested. This method is presently applied to the HJ-1C quick-look system in remote sensing satellite ground stations.

Synthetic Aperture Radar (SAR) image processing requires huge computation amount. Traditionally, this task runs on the workstation or server based on Central Processing Unit (CPU) and is rather time-consuming, hence real-time processing of SAR data is impossible. Based on Compute Unified Device Architecture (CUDA) technology, a new plan of SAR imaging algorithm operated on NVIDIA Graphic Processing Unit (GPU) is proposed. The new proposal makes it possible that the data processing procedure and CPU/GPU data exchanging execute concurrently, especially when SAR data size exceeds total GPU global memory size. Multi-GPU is suitably supported by the new proposal and all of computational resources are fully exploited. It is shown by experiment on NVIDIA K20C and INTEL E5645 that the proposed solution accelerates SAR data processing by tens of times. Consequently, the GPU based SAR processing system with the proposed solution embedded is much more power saving and portable, which makes it qualified to be a real-time SAR data processing system. Experiment shows that SAR data of 36 Mega points can be processed in real-time per second by K20C with the new solution equipped.

Data processing is a time-consuming matter in the field of Synthetic Aperture Radar (SAR). In other ways, Graphic Processing Unit (GPU) have tremendous float-point computational horsepower and very high memory bandwidth, and the developing Compute Unified Device Architecture (CUDA) technology has enabled the GPU to be applied to the general purpose parallel computing. A new method of processing SAR data on GPU is presented in this paper. Compared with the nominal GPU based SAR processing method, number of data transfers between CPU/GPU are reduced from 4 to 1, and CPUs are exploited to cooperate with GPU synchronously. By the proposed method, data Processing is speeded up by 2.3 times, which is verified by the testing on the simulated SAR data.

Objective To explore the association between gallstones and CVD among ethnic minority populations in Guizhou Province, as well as the mediating effect of glomerular filtration rate (GFR) in this association, in order to provide reference suggestions for reducing the burden of CVD. Methods Based on the database of Cohort Study of Native Natural Population in Ethnic Minority Gathering Areas in Southwest China, stratified and multi-stage cluster sampling was used to conduct a baseline survey of ethnic minorities aged 30 - 79 years in Qiandongnan and Qiannan Prefectures of Guizhou Province from 2018 to 2019. Multivariate logistic regression was used to analyze the association between gallstones and CVD, and the mediating effect model was used to evaluate the mediating effect of glomerular filtration rate in the association. Results The detection rate of CVD in Guizhou minority population was 3.16%, among which the detection rates of Dong, Miao and Buyi were 3.27%, 3.07% and 3.12%, respectively. The total detection rate of gallstones was 9.03%. Logistic regression analysis showed that after adjusting for all the variables (model 3), the detection rates of CVD in the total population [OR(95%CI): 1.633(1.269-2.102)], the Dong [OR(95%CI): 1.567(1.077-2.280)], and Miao [OR(95%CI): 1.679(1.055-2.673)], gallstones were positively associated with CVD. No association between gallstones and CVD was found in the Buyi population. Subgroup analysis showed that Dong patients with gallstones < 60 years old were positively correlated with CVD [OR(95%CI): 1.825(1.022-3.258)], gallstone patients without hyperlipidemia [OR(95%CI): 2.151(1.352-3.422)], gallstone patients without hypertension [OR(95%CI): 1.612(1.013-2.565)] were positively correlated with CVD. Miao ≥ 60 years old [OR(95%CI): 1.878(1.038-3.397)], male [OR(95%CI): 1.546(1.212-5.586)], BMI ≥ 24 [OR(95%CI): 1.972(1.160-3.354)], gallstone patients with hypertension [OR(95%CI): 2.264(1.297 - 5.429)] were positively correlated with CVD. Mediation analysis revealed that the glomerular filtration rate accounted for 16.96%, 12.08%, 17.43%, and 14.52% of the mediating effect between gallstones and CVD in the total population, Dong, Miao, and Buyi people, respectively. Conclusion Gallstones are positively correlated with CVD in the Dong and Miao populations in Guizhou Province, especially in the overweight and hypertension population of the Miao nationality. There is no association between gallstones and CVD in the Buyi population. Glomerular filtration rate has a partial mediating effect between gallstones and CVD. [ABSTRACT FROM AUTHOR]

Objective To investigate the prevalence and influencing factors of abnormal bone mass in postmenopausal women of Dong and Miao ethnic groups in Guizhou Province, and to establish a nomogram prediction model and verify it, so as to provide theoretical basis for the prevention of abnormal bone mass in ethnic minority postmenopausal women in Guizhou Province. Methods This study was a cross-sectional study. In total 3 208 postmenopausal women of Dong and Miao ethnic groups were selected from the cohort study database of natural population of ethnic minorities in southwest China, and ultrasonic bone densitometer was used to measure calcaneal bone mineral density (BMD). The concentrations of cadmium, cobalt, copper, chromium, iron, mercury, manganese, molybdenum, nickel, lead, strontium, vanadium, and zinc in urine were determined by inductively coupled plasma mass spectrometer, and the relationship between urine metal, demographic characteristics, reproductive characteristics, ethnic diet, and BMD was analyzed by binary logistic regression, and the risk prediction model of bone mass abnormality was established. Results A total of 3 208 people were included in the study, and a total of 1 520 people with abnormal bone mass were detected. The detection rate of abnormal bone mass was 47.38%. Based on age (OR=1.098, 95%CI: 1.083-1.113), history of bone fracture (OR=0.560, 95%CI: 0.395-0.794), age of menopause (OR=0.965, 95%CI: 0.949-0.982), number of live births (OR=0.900, 95%CI: 0.818-0.990), use of contraceptive (OR=0.708, 95%CI: 0.555-0.901), total physical activity (OR=0.989, 95%CI: 0.984-0.994), urinary cadmium (OR=1.060, 95%CI:1.009-1.113), and urinary chromium (OR=1.004, 95%CI: 1.001-1.008) were independent influencing factors of abnormal bone mass. To establish a predictive model Logit (P) for predicting the risk of abnormal bone mass in postmenopausal women: Logit (") =- 2.170+0.093 * (age)-0.580 * (history of bone fracture)-0.035 * (menopausal age)-0.105 * (number of live births)-0.346* (whether or not you have taken contraceptive)-0.011 * (total physical activity) + 0.058 * (urinary cadmium) + 0.004 * (urinary chromium). The area under the receiver operating characteristic curve of the model was 0.722. The nomogram was drawn and verified internally. The results showed that the calibration curve predicted by the model for abnormal bone mass was basically consistent with the actual curve, and the fitting effect was good. Conclusion Cadmium and chromium are independent risk factors of abnormal bone mass, indicating that metal exposure can affect the occurrence and development of abnormal bone mass. The prediction model and score diagram of bone mass abnormality have good predictive ability, which provides a reference for screening abnormal bone mass of minority postmenopausal women in Guizhou Province. [ABSTRACT FROM AUTHOR]

In order to enhance the support for groundwater development and utilization, as well as pollution control and prevention in Fengtai District, Beijing, a comprehensive study was conducted based on long-term monitoring data of shallow groundwater in the eastern area of Yongding River during the dry season. The mathematical statistics, Piper diagram, Gibbs diagram, and ion ratio analysis and other methods were employed to explore the pattern of groundwater hydrochemical evolution, the formation mechanism, and sources of pollution in Fengtai District. The findings were as follows:① Overall, the current groundwater quality in the study area was poor. The average concentration of each index in groundwater increased and then decreased from 1976 to the present. The pollution range of Cl - , SO 4 2- , and TH generally expanded, whereas the pollution range of TDS and NO 3 - expanded before 2005 and then decreased with 2005 as the turning point. ② The hydrochemical types of groundwater samples displayed a complex regional variation each year, as well as along the groundwater direction. The dominant anion in groundwater was HCO 3 - , and the dominant cation was Ca 2+ each year. The number of groundwater hydrochemical types in 1976 was 8, in which the predominant type was HCO 3 ·SO 4 -Ca·Mg·Na, accounting for 40%. However, the number of groundwater hydrochemical types in 2021 was 17, in which the predominant type was HCO 3 ·Cl·SO 4 -Ca·Na·Mg, accounting for 23.88%. The groundwater hydrochemical type showed a complex trend within the region and upstream along the flow direction each year, whereas the migration characteristics of groundwater samples, as depicted on the Piper diagram, indicated that the hydrochemical components of groundwater were significantly affected by human activities during its evolution. ③ The groundwater chemistry in the study area was influenced by both rock weathering and evaporative crystallization processes, with evaporation playing a major role. The alternation of groundwater cations was relatively weak, and the dissolution of carbonate minerals served as the primary source of Ca 2+ and Mg 2+ . ④ The ion ratio analysis suggested that exogenous sources, mainly agricultural activities and urban sewage, contributed to the input of NO 3 - and Cl - . The pollution impact from agricultural activities was significant before 2005, which aligned with the historical presence of numerous seepage pits, seepage wells, and direct discharge of industrial and domestic sewage for irrigation purposes in the study area. These activities were closely associated with the high levels of pollution. However, pollution input from agricultural activities notably decreased in 2021, likely due to the effective implementation of water environmental protection programs and action plans in recent years.

Phytoplankton is frequently utilized in the assessment of water ecological health, and a great number of related studies have been conducted in China; however, most of them are limited in scope. A phytoplankton survey was carried out at the basin scale in this study. A total of 139 sampling sites were set up in crucial locations of the main stream, from the Yangtze River's source region to the estuary, as well as the eight primary tributaries and the Three Gorges' tributaries. In the Yangtze River Basin, phytoplankton was found in seven phyla and 82 taxa, with Cryptophyta, Cyanophyta, and Bacillariophyta being the dominant species. To begin, the composition of phytoplankton communities in various sections of the Yangtze River Basin was studied, and LEfSe was utilized to identify highly enriched species in different regions. The association between phytoplankton communities and environmental factors in different sections of the Yangtze River Basin was then investigated using CCA. The generalized linear model demonstrated that TN and TP were strongly positively linked with phytoplankton density at the basin scale, whereas TITAN analysis identified the environmental indicator species and their corresponding optimal growth threshold range. Finally, the study assessed each Yangtze River Basin Region in terms of biotic and abiotic factors. Although the results of the two aspects were incongruent, the analysis of all indicators using the random forest method can yield comprehensive and objective ecological evaluation results for each section of the Yangtze River Basin.

To explore the periphytic algae community structure in the Yangtze River basin, samples were collected from 130 sampling sites, including the source to the estuary along the mainstream of the Yangtze River, eight primary tributaries, and the tributary of the Three Gorges area. The periphytic algae densities of different areas in the mainstream of the Yangtze River ranked from high to low were the upstream area, source area, middle and lower area, and the Jinsha River. The high periphytic algae density in the upstream area was associated with the shift in nutrition level, and the high periphytic algae density in the source area was associated with human activity. The spatial pattern of the periphytic algae community in the whole main stream from west to east presented the alternating dominance of Bacillariophyta and Cyanophyta; the Bacillariophyta ( Navicula ) had a competitive advantage in the main stream, and the distribution of the periphytic algae community was driven by total nitrogen, total phosphorus, and pH. For the tributary of the Yangtze River, the periphytic algae density in the Three Gorges tributary area was far higher than those in the eight primary tributaries; the periphytic algae community was dominated by Cyanophyta ( Lyngbya ), which had a competitive advantage in the tributaries of the Yangtze River. The distribution of the periphytic community was driven by dissolved oxygen and pH. According to the diversity analysis and assessment, the periphytic algae community in the source area showed lower species richness and higher evenness, thus leading to a high α -diversity and good assessment result (mesosaprobic zone). The middle and lower reaches of the Yangtze River also showed the same assessment result, the mesosaprobic zone. However, the community evenness of the middle and lower reaches was significantly lower than that of the source area, thus making the middle and lower reaches of the Yangtze River have a significantly lower α -diversity than that of the source area. All areas of the Yangtze River showed good water quality assessment; however, different areas had different WQI index numbers, and the assessment results of the WQI index were inconsistent with the results of the aquatic assessment. Therefore, a comprehensive assessment of aquatic ecosystem health should use both aquatic assessments and water quality assessments.

To explore the bacterioplankton community structure in the Yangtze River basin, water samples were collected from 177 sampling sites, including the source to the estuary along the mainstream of the Yangtze River, eight primary tributaries, and several lakes and reservoirs. The 16S rRNA genes were used to explore the bacterioplankton communities based on single molecule real-time sequencing, with the aim to study the diversity and community characteristics in a border sampling area and higher species annotation accuracy. Based on α -diversity analysis, the river area had higher species richness than that of the lake/reservoir area, resulting in these two areas having different bacterioplankton community diversities. Based on the β diversity analysis, the bacterioplankton showed different community compositions between the river and lake/reservoir areas; temperature was the key environmental factor for the river area, and pH was the key environmental factor for the lake/reservoir area. In order to study the influence of different bacterioplankton communities, this study further investigated the species, function, and community differences between the river and lake/reservoir areas. The results were as follows:for the river area, the eutrophication level gradually increased from west to east along the mainstream of the Yangtze River, resulting in a gradually increased relative abundance of specific species. The lake/reservoir area had a higher risk of cyanobacteria bloom, and the opportunistic pathogen had a high relative abundance in the Danjiangkou Reservoir, indicating a higher ecological risk. For species composition, the river and lake/reservoir areas shared most OTUs (84%); however, some uncultured bacteria showed a high relative abundance in the Yangtze River, meaning the bacterioplankton of the Yangtze River basin still requires further study. In general, the river and lake/reservoir shared most species; however, the different bacterioplankton diversity, community composition, and enriched species made the river and lake/reservoir have different key environmental factors, and they also showed differences in ecological functions.

Spectral feature fitting (SFF) algorithm has been frequently used since 1990s. A modified spectral feature fitting method is introduced here, which can solve some drawback of the general algorithm. The method mentioned here combines SFF with user-defined constraints in spectral absorption feature to extract more accurate target information from hyperspectral image. Two experiments are presented herein, in which three algorithms are used to obtain mineral information from hyperspectral data with different space resolution and SNR. Muscovite, calcite and chlorite etc. are extracted by general SFF, modified SFF and spectral angle mapping (SAM) respectively, and the result indicates that modified SFF algorithm is more effective in differentiating subtle spectral feature and obtaining accurate mineral information. The experiments also demonstrate that the algorithm mentioned here is validated in mineral information extraction.