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Phase-modulator-generated laser for Raman transition is widely used in atom gravimeters to simplify a system and improve robustness. However, the induced additional sidebands (ASBs) lead to systematic errors in gravity measurement. This work presents a novel, to our knowledge, method to generate an optical single-sideband (OSSB) laser for Raman transition through phase modulation based on a Faraday anomalous dispersion atomic filter (FADOF). The experimental result indicates that it can reduce the additional sidebands with a signal-to-noise ratio (SNR, the intensity ratio of carrier and unwanted sidebands) of better than 50â dB, and the phase shift caused by ASBs is demonstrated to be effectively suppressed from 358.8 to 2.2â mrad. Furthermore, this system has already been applied on an atom gravimeter to achieve a primary gravity measurement. It shows that the FADOF-based Raman laser system is a new scheme for a compact atom absolute gravimeter.
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Gully erosion is a serious global environmental problem associated with land degradation and ecosystem security. Examining the influencing factors of gullies and determining susceptibility hold significance in environmental sustainability. The study evaluates the spatial distribution, influencing factors, and susceptibility of gullies in the Sunshui River Basin in Sichuan Province, Southwest China. The frequency ratio method supported by satellite images and the gully inventory dataset (1614 gully head points) with different influencing factors were applied to assess the distribution and susceptibility of gullies. Additionally, gully head points were grouped into a training set (70%, 1130 points) and a test set (30%, 484 points). Spatial distribution results indicated that most gullies are located in the middle and upper part of the basin, characterized by moderate elevation (2100-3300 m), steep slopes (11.63-27.34°), abandoned farmland, and Cambisols soil, and fewer gullies are located in lower part characterized by lower elevation, gentle slopes, and low vegetation coverage. Land use and land cover influence on susceptibility is significantly greater than other factors with a prediction rate of 33.9, especially farmland abandonment, while the occurrence of gullies is also more often on southwest-orientated slopes. Gully susceptibility highlighted that the study area affected by the very low, low, moderate, high, and very high susceptibilities to these gullies covered an area of about 16%, 23%, 32%, 26%, and 3% of the total basin respectively, which indicates 61% of the study area is susceptible to gully erosion. Moderate to high susceptibility is situated in the upper and middle part, consistent with the spatial distribution of gullies in the basin, and very high susceptibility (3%) is distributed in both the lower and upper parts of the basin. These results have important implications for soil loss control, land planning, and integrated watershed management in the mountainous areas of Southwest China.
Assuntos
Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Rios , China , Monitoramento Ambiental/métodos , Rios/química , Animais , Ecossistema , Conservação dos Recursos Naturais , Erosão do SoloRESUMO
Objective: To investigate the performance of multiparametric magnetic resonance imaging (MRI)-based radiomics models in differentiating early stage of cervical cancer (Stage I-IIa vs. IIb-IV). Methods: One hundred patients with cervical cancer who underwent preoperative MRI between June 2020 and March 2022 were retrospectively enrolled. Training (n = 70) and testing cohorts (n = 30) were assigned by stratified random sampling. The clinical and pathological features, including age, histological subtypes, tumor grades, and node status, were compared between the two cohorts by t-test or chi-square test. Radiomics features were extracted from each volume of interest (VOI) on T2-weighted images (T2WI) and apparent diffusion coefficient (ADC) maps. The data balance of the training cohort was resampled by synthesizing minority oversampling techniques. Subsequently, the adiomics signatures were constructed by the least absolute shrinkage and selection operator algorithm and minimum-redundancy maximum-relevance with 10-fold cross-validation. Logistic regression was applied to predict the cervical cancer stages (low [I-IIa]) and (high [IIb-IV] FIGO stages). The receiver operating characteristic curve (area under the curve [AUC]) and decision curve analysis were used to assess the performance of the radiomics model. Results: The characteristics of age, histological subtypes, tumor grades, and node status were not significantly different between the low [I-IIa] and high [IIb-IV] FIGO stages (p > 0.05 for both the training and test cohorts). Three models based on T2WI, ADC maps, and the combined were developed based on six radiomics features from T2WI and three radiomics features from ADC maps, with AUCs of 0.855 (95% confidence interval [CI], 0.777-0.934) and 0.823 (95% CI, 0.727-0.919), 0.861 (95% CI, 0.785-0.936) and 0.81 (95% CI, 0.701-0.918), 0.934 (95% CI, 0.884-0.984) and 0.902 (95% CI, 0.832-0.972) in the training and test cohorts. Conclusion: The radiomics models combined T2W and ADC maps had good predictive performance in differentiating the early stage from locally advanced cervical cancer.
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OBJECTIVES: To assess the impact of a patient-based self-assessed fatigue intervention aimed at promoting early postoperative ambulation. DESIGN: Prospective randomised controlled trial. SETTING: Single-centre, conducted at the Obstetrics and Gynaecology Department of the Xiangyang Central Hospital, China. PARTICIPANTS: Eligible were adult patients undergoing elective gynaecologic oncologic surgery. INTERVENTIONS: The intervention group utilised a modified Borg Rating of Perceived Experience (RPE) scale for self-assessment of fatigue levels. The control group followed fixed-activity distance guidelines postoperatively. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the self-reported the time to first flatus postoperatively. Secondary outcomes encompassed the time to first defecation, incidence of moderate-to-severe abdominal distention, ileus, postambulation adverse events (nausea, vomiting and dizziness), patient satisfaction with early ambulation instructions, compliance with early ambulation and average hospital costs and length of stay. RESULTS: Between June 2021 and October 2022, 552 patients were enrolled. The self-assessed fatigue intervention group demonstrated non-inferior the time to first flatus compared with the fixed-activity distance assessment group (25.59±14.59 hours vs 26.10±14.19 hours, pnon-inferiority<0.001). Compliance with activity was higher in the intervention group (49.40% vs 36.02%, p<0.001), although it did not reach 50%. The intervention group also exhibited significantly higher mean hospital costs, length of stay and incidence of moderate-to-severe abdominal distention (p<0.001). CONCLUSIONS: The self-assessed fatigue intervention for early postoperative ambulation in gynaecologic oncology patients shows promise as an effective strategy; however, compliance is suboptimal. An intervention based on mandatory, yet reasonable, fixed-activity distance may represent the most viable current approach. Further research is warranted to confirm these findings. TRIAL REGISTRATION NUMBER: CTR2100046035.