Deep inelastic scattering, QCD, and generalized vector dominance

We provide a formulation of generalized vector dominance (GVD) for low–x deep-inelastic scattering that explicitly incorporates the transition and a QCD-inspired ansatz for the forward-scattering amplitude. The destructive interference originally introduced in off-diagonal GVD is recovered in the present formulation and traced back to the generic structure of two-gluon-exchange as incorporated into the notion of colour transparency. Asymptotically, the transverse photoabsorption cross section behaves as , implying a logarithmic violation of scaling for , while the longitudinal-to-transverse ratio decreases as . Received: 27 August 1999 / Revised version: 19 November 1999 / Published online: 17 February 2000     

Lexical frequency and acoustic reduction in spoken Dutch

This study investigates the effects of lexical frequency on the durational reduction of morphologically complex words in spoken Dutch. The hypothesis that high-frequency words are more reduced than low-frequency words was tested by comparing the durations of affixes occurring in different carrier words. Four Dutch affixes were investigated, each occurring in a large number of words with different frequencies. The materials came from a large database of face-to-face conversations. For each word containing a target affix, one token was randomly selected for acoustic analysis. Measurements were made of the duration of the affix as a whole and the durations of the individual segments in the affix. For three of the four affixes, a higher frequency of the carrier word led to shorter realizations of the affix as a whole, individual segments in the affix, or both. Other relevant factors were the sex and age of the speaker, segmental context, and speech rate. To accommodate for these findings, models of speech production should allow word frequency to affect the acoustic realizations of lower-level units, such as individual speech sounds occurring in affixes.     

A class of problems where dual bounds beat underestimation bounds

We investigate the problem of minimizing a nonconvex function with respect to convex constraints, and we study different techniques to compute a lower bound on the optimal value: The method of using convex envelope functions on one hand, and the method of exploiting nonconvex duality on the other hand. We investigate which technique gives the better bound and develop conditions under which the dual bound is strictly better than the convex envelope bound. As a byproduct, we derive some interesting results on nonconvex duality.     

Induced fermionic interactions in theories with general nonlinearly realized SSB

We consider a model with nonlinear SSB, which can be considered as a limiting case of the electroweak SM whenM _H→∞. It possesses a chain of hidden local gauge symmetries yielding a series of heavy gauge boson triplets, which can be interpreted as effects of the strong self-interactions of the scalar sector and are able to infect via mixing low energy quantities. The theory is non-renormalizable and, therefore, new Lagrangian terms are induced at each loop order. We investigate these quantum-induced interactions (which are of non-standard type) of fermions and vector bosons, and show that they can be expressed in additional Lagrangian terms which obey the symmetry of the original theory.     

Two distinct manganese(II) complexes with hexadentate 1,3-propanediaminetetraacetate ligand: The ability of metal(II) complexes with 1,3-pdta ligand to form solid solutions

The ability of Mn(II) ion to form two distinctly different complexes with 1,3-propanediaminetetraacetate (1,3-pdta) ligand has been demonstrated by performing X-ray analyses of their crystalline Mg(II) salts. The two types of Mn(II) complexes have been obtained by different synthetic routes and their crystals constitute, respectively, the solid solution of the composition [Mg(H₂O)₆][Mg_0.5Mn_0.5(1,3-pdta)] · 2H₂O (1) and the ordered crystals of the composition [Mg(H₂O)₆][Mn(1,3-pdta)(H₂O)] · 2H₂O (2). In both, six- 1 and seven-coordinated 2 Mn(II) complexes the 1,3-pdta ligand acts as a hexadentate. As 2 makes the second example of the seven-coordinated 1,3-pdta complex with divalent transition metal ion, the other being the [Mg(H₂O)₆][Cd(1,3-pdta)(H₂O)] · 2H₂O (3) complex, the paper reports the results of X-ray investigations of both of these complexes at 130 K.     

Micro-well arrays for 3D shape control and high resolution analysis of single cells

In addition to rigidity, matrix composition, and cell shape, dimensionality is now considered an important property of the cell microenvironment which directs cell behavior. However, available tools for cell culture in two-dimensional (2D) versus three-dimensional (3D) environments are difficult to compare, and no tools exist which provide 3D shape control of single cells. We developed polydimethylsiloxane (PDMS) substrates for the culture of single cells in 3D arrays which are compatible with high-resolution microscopy. Cell adhesion was limited to within microwells by passivation of the flat upper surface through 'wet-printing' of a non-fouling polymer and backfilling of the wells with specific adhesive proteins or lipid bilayers. Endothelial cells constrained within microwells were viable, and intracellular features could be imaged with high resolution objectives. Finally, phalloidin staining of actin stress fibers showed that the cytoskeleton of cells in microwells was 3D and not limited to the cell-substrate interface. Thus, microwells can be used to produce microenvironments for large numbers of single cells with 3D shape control and can be added to a repertoire of tools which are ever more sought after for both fundamental biological studies as well as high throughput cell screening assays.     

Localized and efficient estimators for obstacle problems in the context of standard residual estimators

In order to localize the estimator contributions with respect to the active set of constraints special error measures and residual-type estimators have been derived for different variational inequalities [2–4]. Considering the classical obstacle problem, we summarize the basic ideas and draw a relation to estimators for linear elliptic problems without constraints. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Increased zinc accumulation in mineralized osteosarcoma tissue measured by confocal synchrotron radiation micro X‐ray fluorescence analysis

Abnormal tissue levels of certain trace elements such as zinc (Zn) were reported in various types of cancer. Little is known about the role of Zn in osteosarcoma. Using confocal synchrotron radiation micro X‐ray fluorescence analysis, we characterized the spatial distribution of Zn in high‐grade sclerosing osteosarcoma of nine patients (four women/five men; seven knee/one humerus/one femur) following chemotherapy and wide surgical resection. Levels were compared with adjacent normal tissue. Quantitative backscattered electron imaging as well as histological examinations was also performed. On average, the ratio of medians of Zn count rates (normalized to calcium) in mineralized tumor tissue was about six times higher than in normal tissue. There was no difference in Zn levels between tumor fraction areas with a low fraction and a high fraction of mineralized tissue, which were clearly depicted using quantitative backscattered electron imaging. Moreover, we found no correlation between the Zn values and the type of tumor regression according to the Salzer‐Kuntschik grading. The underlying mechanism of Zn accumulation remains unclear. Given the emerging data on the role of trace elements in other types of cancer, our novel results warrant further studies on the role of trace elements in bone cancer. Copyright © 2016 The Authors. X‐Ray Spectrometry published by John Wiley & Sons Ltd.