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• Novel mammography image quality assessment using a parametric model observer. • Validation and comparison with current practice in quality assessment through virtual mammography. • 5 images and novel approach result in similar precision as 16 images and current practice. A novel approach is proposed for the determination of contrast-detail curves in mammography image quality assessment. The approach is compared with current practice using virtual mammography. A binary parametric model observer is applied to images of the CDMAM phantom. The observer accounts for the simple disc shaped objects in the phantom and is applied separately to each cell of the phantom. For each of these applications, the area under the ROC curve (AUC) of the model observer is determined. The different AUCs, calculated from different applications of the parametric model observer, are then combined to a single contrast-detail curve quantifying the ability of the observer to detect details in the images. Virtual mammography is developed as a tool to simulate X-ray images of single CDMAM cells and to quantitatively assess the approach in comparison with current practice. It is shown that the proposed approach can lead to similar contrast-detail curves as current practice. The precision of the estimated contrast-detail curves is increased, i.e. using 5 images yields about the same precision for the proposed approach as 16 images when applying current practice. We conclude that contrast-detail curves in mammography image quality assessment can also be determined through the AUC of a binary parametric model observer. Since the proposed approach has higher precision than current practice, it is a promising candidate for contrast-detail analysis in mammography image quality assessment. [ABSTRACT FROM AUTHOR]

Alteration of water flows and consequent hypersalinization caused the death of nearly 70% of mangroves at the Cienaga Grande de Santa Marta, Colombia. Efforts to rehabilitate the ecosystem have been made through the construction of freshwater channels. Mangrove recovery was observed along a freshwater channel and at a small lagoon behind the beach ridge. Factors identified in this study influencing mangrove regeneration are: salinity of surface water, duration and height of flooding, leaching property of soils, dispersal of propagules and presence of fertile trees. Besides mangrove regeneration, a notable extension of freshwater plants was observed in the channel. Trace metal concentrations in sediments from the Magdalena River and its area of influence were investigated before the complete opening of the first channel. A relative comparison indicated that the highest concentrations of Cd, Cu, Ni and Zn were above international recommended limits. However, metal concentrations found in sediments at Clarin Channel did not affect the mangrove recovery. [ABSTRACT FROM AUTHOR]

Abstract: A recently proposed accelerometer model is applied for determining the accelerometer’s output to transient accelerations. The model consists of a linear, second-order differential equation with unknown coefficients. It is proposed to estimate these model parameters from sinusoidal calibration measurements, and an estimation procedure based on linear least-squares is presented. In addition, the uncertainties associated with the estimated parameters are determined utilizing a Monte Carlo simulation technique. The performance of the proposed modelling approach was tested by its application to calibration measurements of two back-to-back accelerometers (ENDEVCO type 2270 and Brüel & Kjær type 8305). For each of the two accelerometers, the model was first estimated from sinusoidal calibration measurements and then used to predict the accelerometer’s behaviour for two shock calibration measurements. Measured and predicted shock sensitivities were found consistent with differences below 1% in most cases which confirms the benefit of the proposed modelling approach. [Copyright &y& Elsevier]