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Nine european national metrology institutes (NMIs) are collaborating in a new project funded by the european metrology research programme (EMRP) to establish traceable dynamic measurement of the mechanical quantities force, pressure, and torque. The aim of this joint research project (JRP) is to develop appropriate calibration methods, mathematical models, and uncertainty evaluation. The duration of the project is 3 years for a global amount of €3.6 million. It began in September 2011.

A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best the optical properties and relative uncertainties of diffusive dilutions prepared with common samples of the two compounds. By exploiting a suitable statistical model, comprehensive reference values at three NIR wavelengths for the intrinsic absorption coefficient of India ink and the intrinsic reduced scattering coefficient of Intralipid-20% were determined with an uncertainty of about 2% or better, depending on the wavelength considered, and 1%, respectively. Even if in this study we focused on particular batches of India ink and Intralipid, the reference values determined here represent a solid and useful starting point for preparing diffusive liquid phantoms with accurately defined optical properties. Furthermore, due to the ready availability, low cost, long-term stability and batch-to-batch reproducibility of these compounds, they provide a unique fundamental tool for the calibration and performance assessment of diffuse optical spectroscopy instrumentation intended to be used in laboratory or clinical environment. Finally, the collaborative work presented here demonstrates that the accuracy level attained in this work for optical properties of diffusive phantoms is reliable.

The task of solving the inverse problem of scatterometry is considered. As a non-imaging indirect optical metrology method the goal of scatterometry is, e.g., to reconstruct the absorber line profiles of lithography masks, i.e., profile parameters such as line width, line height, and side-wall angle (SWA), from the measured diffracted light pattern and to estimate their associated uncertainties. The impact of an appropriate choice of the statistical model for the input data on the reconstructed profile parameters is demonstrated for EUV masks, where light with wavelengths of about 13.5 nm is applied. The maximum likelihood method is proposed to determine more reliable estimations of all model parameters, including the sought profile dimensions. Finally, this alternative approach is applied to EUV measurement data and the results are compared to those obtained by a conventional analysis.

A procedure for the analysis of key comparison data is proposed in the case where the travelling standard shows a deterministic or random drift. It is assumed that some parametric model such as a linear trend is appropriate for modelling the deterministic part of the drift. The random part of the drift is assumed to be adequately described by a random walk model. The chosen drift model is determined by least squares and a model check is carried out. If the model check is satisfied, the derived drift model is applied to determine degrees of equivalence. A star-type sequence is required for the comparison in order to check the adequacy of the random drift model. The procedure is illustrated by its application to simulated data.

The phase of the complex output of a narrow band Gaussian filter is taken to define the latency of the auditory evoked response M100 recorded by magnetoencephalography. It is demonstrated that this definition is consistent with the conventional peak latency. Moreover, it provides a tool for reducing the number of averages needed for a reliable estimation of the latency. Single-event latencies obtained by this procedure can be used to improve the signal quality of the conventional average by latency adjusted averaging.

The Evaluation Guidelines [1] specify general analysis methods for key comparisons of measurement data where their reasonable application is subject to some preconditions. We discuss a real example of comparison data that can be analyzed in formal accordance with the Guidelines. But we prefer a model-based analysis benefiting from the intrinsic relation of the data. Indeed, this method is founded on the principles of the Guidelines. In our example, the laboratories participating in the key comparison have carried out a series of calibration measurements of a particular accelerometer. The values from this series correspond to the measurements at different excitation frequencies. A physical model describing the frequency dependence is known. The proposed model-based analysis estimates the unknown model parameters taking the values from the series of the laboratories simultaneously into account. If the derived model and the data are consistent, the model function gained represents the reference values. The advantage of the model-based analysis is that we utilize the a prioriknowledge we have at our disposal. We obtain better reference values, i.e., the uncertainties associated with the reference values are considerably lower.

A new method is presented for the reconstruction of a one-dimensional wave front on the basis of difference measurements from two shearing interferograms. The proposed algorithm reconstructs any wave front exactly up to an arbitrary constant. The method is not restricted to small shears. However, the shearing parameters have to be chosen such that certain constraints are satisfied. A procedure for determining such shearing parameters is given. In addition, it is shown that the procedure is stable with respect to noise introduced into the differences.

Abstract: The optimization of noisy functions in a few variables only is a common problem occurring in various applications, for instance in finding the optimal choice of a few control parameters in chemical experiments. The traditional tool for the treatment of such problems is the method of Nelder-Mead (NM). In this paper an alternative method based on a trust region approach (TR) is offered and compared to Nelder-Mead. On the standard collection of test functions for unconstrained optimization by Moré et al. [9], TR performs substantially more robust than NM. If performance is measured by the number of function evaluations, TR is on the average twice as fast as NM.

For model identification and parameter estimation in the framework of linear pharmacokinetics it is most often assumed that the disposition function is a finite sum of exponential functions with time constants ?i and associated coefficients Ci. Least-square fitting procedures are used to estimate the coefficients Ci and the corresponding discrete locations ?i on the ?-axes.

The application of Tikhonov regularization to the determination of relaxation and retardation spectra of viscoelastic fluids is discussed using simulated and real experimental data. It is thereby shown that with this method consistent results for relaxation and retardation spectra can be obtained from experimental data for different material functions. Furthermore, the differences between the most frequently used variants of Tikhonov regularization and the maximum entropy method are discussed. For most calculations the program FTIKREG has been used, which is an especially fast and reliable implementation of Tikhonov's regularization method.

Abstract.: The two-body T-matrix is calculated directly as function of two vector momenta for different Malfliet-Tjon-type potentials. At a few hundred MeV projectile energy the total amplitude is quite a smooth function showing only a strong peak in forward direction. In contrast, the corresponding partial-wave contributions, whose number increases with increasing energy, become more and more oscillatory with increasing energy. The angular and momentum dependence of the full amplitude is studied and displayed on as well as off the energy shell as function of positive and negative energies. The behaviour of the T-matrix in the vicinity of bound-state poles and resonance poles in the second energy sheet is studied. It is found that the angular dependence of T exhibits very characteristic properties in the vicinity of those poles, which are given by the Legendre function corresponding to the quantum number either of the bound state or the resonance (or virtual) state. This behaviour is illustrated along numerical examples.

Ten cases of salmonellal splenic abscesses recently documented in various Latin American countries are discussed. All patients were adults; the mean age was 32.6 years, and there was a predominance of males (seven). Predisposing conditions were identified in four cases. All 10 cases were documented by diagnostic imaging techniques; in one case, exploratory diagnostic laparotomy was also performed. Splenectomy was performed on eight patients, while two other patients responded to long courses of intravenous antimicrobial therapy alone. One patient died as the result of perioperative splenic rupture, and two patients underwent second laparotomies because of left subphrenic abscesses. Except for one human immunodeficiency virus-infected individual, all patients were immunocompetent and had large solitary lesions. Salmonella typhi was the predominant organism isolated and was recovered in six of the 10 cases.