Systematic investigation of the elastic proton-deuteron differential cross section at intermediate energies

To investigate the importance of three-nucleon forces (3NF) systematically over a broad range of intermediate energies, the differential cross sections of elastic proton-deuteron scattering have been measured at proton bombarding energies of 108, 120, 135, 150, 170 and 190 MeV at center-of-mass angles between $30^\circ$ and $170^\circ$. Comparisons with Faddeev calculations show unambiguously the shortcomings of calculations employing only two-body forces and the necessity of including 3NF. They also show the limitations of the latest few-nucleon calculations at backward angles, especially at higher beam energies. Some of these discrepancies could be partially due to relativistic effects. Data at lowest energy are also compared with a recent calculation based on \chipt

Proton-deuteron radiative capture cross sections at intermediate energies

Differential cross sections of the reaction $p(d,^3{\rm He})\gamma$ have been measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were obtained with a coincidence setup measuring both the outgoing $^3$He and the photon. The data are compared with modern calculations including all possible meson-exchange currents and two- and three- nucleon forces in the potential. The data clearly show a preference for one of the models, although the shape of the angular distribution cannot be reproduced by any of the presented models.Comment: 6 pages, 6 figures, accepted for publication in EPJ

Wages in high-tech start-ups - do academic spin-offs pay a wage premium?

Due to their origin from universities, academic spin‐offs operate at the forefront of the technological development. Therefore, spin‐offs exhibit a skill‐biased labour demand, i.e. spin‐offs have a high demand for employees with cutting edge knowledge and technical skills. In order to accommodate this demand, spin‐offs may have to pay a relative wage premium compared to other high‐tech start‐ups. However, neither a comprehensive theoretical assessment nor the empirical literature on wages in start‐ups unambiguously predicts the existence and the direction of wage differentials between spin‐offs and non‐spin‐offs. This paper addresses this research gap and examines empirically whether or not spin‐offs pay their employees a wage premium. Using a unique linked employer‐employee data set of German high‐tech start‐ups, we estimate Mincer‐type wage regressions applying the Hausman‐Taylor panel estimator. Our results show that spin‐offs do not pay a wage premium in general. However, a notable exception from this general result is that spin‐offs that commercialise new scientific results or methods provide higher wages to employees with linkages to the university sector – either as university graduates or as student workers

UPGRADE OF THE TIMING SYSTEM AT THE AUSTRALIAN SYNCHROTRON

Abstract The Australian Synchrotron (AS) timing system is based on a hybrid design: an Event Generator-Event Receiver (EVG-EVR) system creates the injection trigger and various clocks, while a network of digital delay generators adjusts pulse delays and widths. This architecture, combined with a storage ring fill pattern monitor, allows the targeting of injection into specific buckets in the storage ring. Nevertheless, more demanding needs from the machine and the beamlines require an upgrade of the system. Delay generators will be removed and replaced by EVRs. This will allow fixed or variable frequency clocks to be made available to beamlines or to trigger diagnostic hardware in a flexible way, while reducing jitters to below 100 ps

The effect of preprocessing on convolutional neural networks for medical image segmentation

In recent years, deep learning has become the leading method for medical image segmentation. While the majority of studies focus on developments of network architectures, several studies have shown that non-architectural factors also play a substantial role in performance improvement. An important factor is preprocessing. However, there is no agreement on which preprocessing steps work best for different applications. The aim of this study was to investigate the effect of preprocessing on model performance. To this end, we conducted a systematic evaluation of 24 preprocessing configurations on three clinical application datasets (brain, liver, and knee). Different configurations of normalization, region of interest selection, bias field correction, and resampling methods were applied before training one convolutional neural network. Performance varied up to 64 percentage points between configurations within one dataset. Across the three datasets, different configurations performed best. In conclusion, to improve model performance, preprocessing should be tuned to the specific segmentation application

Schematic representations in arithmetical problem solving: Analysis of their impact on grade 4 students

While the value of ‘schematic representations’ in problem solving requires no further demonstration, the way in which students should be taught how to construct these representations invariably gives rise to various debates. This study, conducted on 146 grade 4 students in Luxembourg, analyzes the effect of two types of ‘schematic representation’ (diagrams vs. schematic drawings) on the solving of arithmetical problems. The results show that the presence of schematic representations has a clear positive effect on overall student performance and that a non negligible proportion of students manage to reuse the representations encountered in order to solve new problems. While showing an effect slightly in favor of diagrams as opposed to schematic drawings, our results do not really permit us to draw any conclusions about the form that these representations should take, in particular since a differential effect was observed depending on the type of problem