Improved Measurements of Samples Simulating Corrosion in Lap-Seams of Aluminum Aircraft

AC magnetic bridges offer a technique for continuous electromagnetic scanning of surfaces and lap seams of aging aluminum aircraft to detect material losses due to corrosion. AC magnetic bridges are particularly responsive to changes in conductance because nearly all the electromagnetic field generated is in contact with the sample as compared with conventional eddy-current devices where the high reluctance of that portion of the magnetic field not in contact with the sample has a tendency to mask the small portion of the field in contact with the sample. Further, the eddy-current technique masks the effect of the electromagnetic interaction with the sample through the requirement that the changes produced by changes in the sample be detected in series with the impedance of the eddy-current coil. This latter effect requires the use of relative high frequencies in conventional eddy-current devices. Use of the ac magnetic bridge (the bridge) solves all of these problems while providing the physical convenience of conventional eddy-current scans if such a scans were effective. The frequencies used for bridge operation are usually of the order of 100 Hz to 20 kHz and offer greater sample penetration than conventional eddy-current devices which usually operate well above this range. Further, ac magnetic bridges maintain their sensitivity to material loss at values of lift off of 20 mils or greater, well above the usual values of paint coating thicknesses

Saw-Cut Scanning Patterns

The scanning of surface saw cuts can yield clues both about the interaction of nondestructive evaluation (NDE) devices with samples and the ability to detect and characterize flaws of other shapes. In this case, the device is a modified AC magnetic bridge (the bridge) which has been described elsewhere [1,2,3]. Electrical bridges can be operated in two modes: Off-null operation occurs when the bridge output is minimized (nulled) and the reaction of the bridge to various samples is judged by changes in the output voltage. Off-null operation is principally used for control. Renull operation occurs when the bridge is nulled for each sample and the physical parameters required to null the bridge (usually resistance and/or resistance and capacitance) can be used to determine physical differences in the samples

Comparisons of the Behavior of Real and Imaginary Reluctances Between Samples of 6061 Aluminum as a Function of Grain Size

Relative measurements of real and imaginary reluctances were made as a function of sample thickness on both rolled and cast 6061 aluminum samples using an ac magnetic bridge. Samples were both nonannealed and annealed. Evidence was developed that the imaginary reluctance (which is shown here to respond to the conductivity of samples) responds more to the bulk properties of the samples while real reluctance apparently responds more to surface conditions such as surface residual stress

The European Federation of Organisations for Medical Physics Policy Statement No. 6.1: Recommended Guidelines on National Registration Schemes for Medical Physicists

This EFOMP Policy Statement is an update of Policy Statement No. 6 first published in 1994. The present version takes into account the European Union Parliament and Council Directive 2013/55/EU that amends Directive 2005/36/EU on the recognition of professional qualifications and the European Union Council Directive 2013/59/EURATOM laying down the basic safety standards for protection against the dangers arising from exposure to ionising radiation. The European Commission Radiation Protection Report No. 174, Guidelines on Medical Physics Expert and the EFOMP Policy Statement No. 12.1, Recommendations on Medical Physics Education and Training in Europe 2014, are also taken into consideration. The EFOMP National Member Organisations are encouraged to update their Medical Physics registration schemes where these exist or to develop registration schemes taking into account the present version of this EFOMP Policy Statement (Policy Statement No. 6.1"Recommended Guidelines on National Registration Schemes for Medical Physicists")

The prescribed mean curvature equation in weakly regular domains

We show that the characterization of existence and uniqueness up to vertical translations of solutions to the prescribed mean curvature equation, originally proved by Giusti in the smooth case, holds true for domains satisfying very mild regularity assumptions. Our results apply in particular to the non-parametric solutions of the capillary problem for perfectly wetting fluids in zero gravity. Among the essential tools used in the proofs, we mention a \textit{generalized Gauss-Green theorem} based on the construction of the weak normal trace of a vector field with bounded divergence, in the spirit of classical results due to Anzellotti, and a \textit{weak Young's law} for $(\Lambda,r_{0})$-minimizers of the perimeter.Comment: 23 pages, 1 figure --- The results on the weak normal trace of vector fields have been now extended and moved in a self-contained paper available at: arXiv:1708.0139

Proliferation and estrogen signaling can distinguish patients at risk for early versus late relapse among estrogen receptor positive breast cancers

Introduction: We examined if a combination of proliferation markers and estrogen receptor (ER) activity could predict early versus late relapses in ER-positive breast cancer and inform the choice and length of adjuvant endocrine therapy. Methods: Baseline affymetrix gene-expression profiles from ER-positive patients who received no systemic therapy (n = 559), adjuvant tamoxifen for 5 years (cohort-1: n = 683, cohort-2: n = 282) and from 58 patients treated with neoadjuvant letrozole for 3 months (gene-expression available at baseline, 14 and 90 days) were analyzed. A proliferation score based on the expression of mitotic kinases (MKS) and an ER-related score (ERS) adopted from Oncotype DX® were calculated. The same analysis was performed using the Genomic Grade Index as proliferation marker and the luminal gene score from the PAM50 classifier as measure of estrogen-related genes. Median values were used to define low and high marker groups and four combinations were created. Relapses were grouped into time cohorts of 0-2.5, 0-5, 5-10 years. Results: In the overall 10 years period, the proportional hazards assumption was violated for several biomarker groups indicating time-dependent effects. In tamoxifen-treated patients Low-MKS/Low-ERS cancers had continuously increasing risk of relapse that was higher after 5 years than Low-MKS/High-ERS cancers [0 to 10 year, HR 3.36; p = 0.013]. High-MKS/High-ERS cancers had low risk of early relapse [0-2.5 years HR 0.13; p = 0.0006], but high risk of late relapse which was higher than in the High-MKS/Low-ERS group [after 5 years HR 3.86; p = 0.007]. The High-MKS/Low-ERS subset had most of the early relapses [0 to 2.5 years, HR 6.53; p < 0.0001] especially in node negative tumors and showed minimal response to neoadjuvant letrozole. These findings were qualitatively confirmed in a smaller independent cohort of tamoxifen-treated patients. Using different biomarkers provided similar results. Conclusions: Early relapses are highest in highly proliferative/low-ERS cancers, in particular in node negative tumors. Relapses occurring after 5 years of adjuvant tamoxifen are highest among the highly-proliferative/high-ERS tumors although their risk of recurrence is modest in the first 5 years on tamoxifen. These tumors could be the best candidates for extended endocrine therapy

The Atlantic Ocean at the last glacial maximum: 1. Objective mapping of the GLAMAP sea-surface conditions

Recent efforts of the German paleoceanographic community have resulted in a unique data set of reconstructed sea-surface temperature for the Atlantic Ocean during the Last Glacial Maximum, plus estimates for the extents of glacial sea ice. Unlike prior attempts, the contributing research groups based their data on a common definition of the Last Glacial Maximum chronozone and used the same modern reference data for calibrating the different transfer techniques. Furthermore, the number of processed sediment cores was vastly increased. Thus the new data is a significant advance not only with respect to quality, but also to quantity. We integrate these new data and provide monthly data sets of global sea-surface temperature and ice cover, objectively interpolated onto a regular 1°x1° grid, suitable for forcing or validating numerical ocean and atmosphere models. This set is compared to an existing subjective interpolation of the same base data, in part by employing an ocean circulation model. For the latter purpose, we reconstruct sea surface salinity from the new temperature data and the available oxygen isotope measurements