13,513 research outputs found
Remote sensing observatory validation of surface soil moisture using Advanced Microwave Scanning Radiometer E, Common Land Model, and ground based data: Case study in SMEX03 Little River Region, Georgia, U.S.
Optimal soil moisture estimation may be characterized by intercomparisons among remotely sensed measurements, groundâbased measurements, and land surface models. In this study, we compared soil moisture from Advanced Microwave Scanning Radiometer E (AMSRâE), groundâbased measurements, and a SoilâVegetationâAtmosphere Transfer (SVAT) model for the Soil Moisture Experiments in 2003 (SMEX03) Little River region, Georgia. The Common Land Model (CLM) reasonably replicated soil moisture patterns in dry down and wetting after rainfall though it had modest wet biases (0.001â0.054 m3/m3) as compared to AMSRâE and ground data. While the AMSRâE average soil moisture agreed well with the other data sources, it had extremely low temporal variability, especially during the growing season from May to October. The comparison results showed that highest mean absolute error (MAE) and root mean squared error (RMSE) were 0.054 and 0.059 m3/m3 for short and long periods, respectively. Even if CLM and AMSRâE had complementary strengths, low MAE (0.018â0.054 m3/m3) and RMSE (0.023â0.059 m3/m3) soil moisture errors for CLM and soil moisture low biases (0.003â0.031 m3/m3) for AMSRâE, care should be taken prior to employing AMSRâE retrieved soil moisture products directly for hydrological application due to its failure to replicate temporal variability. AMSRâE error characteristics identified in this study should be used to guide enhancement of retrieval algorithms and improve satellite observations for hydrological sciences
Intra-cavitary uterine pathology in women with abnormal uterine bleeding: a prospective study of 1220 women.
OBJECTIVES: Our primary aim was to assess how patients characteristics, bleeding pattern, sonographic endometrial thickness (ET) and additional features at unenhanced ultrasound examination (UTVS) and at fluid instillation sonography (FIS) contribute to the diagnosis of intracavitary uterine pathology in women presenting with abnormal uterine bleeding (AUB). We further aimed to report the prevalence of pathology in women presenting with AUB. METHODS: 1220 consecutive women presenting with AUB underwent UTVS, colour Doppler imaging (CDI) and FIS. Most women (n = 1042) had histological diagnosis. RESULTS: Mean age was 50 years and 37% were postmenopausal. Of 1220 women 54% were normal, polyps were diagnosed in 26%, intracavitary fibroids in 11%, hyperplasia without atypia in 4% and cancer in 3%. All cancers were diagnosed in postmenopausal (7%) or perimenopausal (1%) women. ET had a low predictive value in premenopausal women (LR+ and LR- of 1.34 and 0.74, respectively), while FIS had a LR+ and LR- of 6.20 and 0.24, respectively. After menopause, ET outperformed all patient characteristics for the prediction of endometrial pathology (LR+ and LR- of 3.13 and 0.24). The corresponding LR+ and LR- were 10.85 and 0.71 for CDI and 8.23 and 0.26 for FIS. CONCLUSION: About half of the women presenting to a bleeding clinic will have pathology. In premenopausal women, benign lesions are often the cause of AUB. For the prediction of intracavitary pathology ET is of little value in premenopausal women. CDI and FIS substantially improve the diagnostic accuracy
- âŠ