611 research outputs found
How cost-effective is public R&D in stimulating firm innovation?
This paper assesses the impact of public R&D on firm R&D using patent application data on the county and firm level in Germany. We address the endogeneity of public R&D by employing an instrumental variable estimator that uses lagged institutional funding for research institutes and universities as excluded instruments. We find that one additional public patent application generates 3.5 firm patent applications in the median county, but also that the relationship turns negative for high levels of public R&D. We estimate the public costs per firm patent to be between 0.8 and 1.5 million EURO
VINNA for Neonates -- Orientation Independence through Latent Augmentations
Fast and accurate segmentation of neonatal brain images is highly desired to
better understand and detect changes during development and disease. Yet, the
limited availability of ground truth datasets, lack of standardized acquisition
protocols, and wide variations of head positioning pose challenges for method
development. A few automated image analysis pipelines exist for newborn brain
MRI segmentation, but they often rely on time-consuming procedures and require
resampling to a common resolution, subject to loss of information due to
interpolation and down-sampling. Without registration and image resampling,
variations with respect to head positions and voxel resolutions have to be
addressed differently. In deep-learning, external augmentations are
traditionally used to artificially expand the representation of spatial
variability, increasing the training dataset size and robustness. However,
these transformations in the image space still require resampling, reducing
accuracy specifically in the context of label interpolation. We recently
introduced the concept of resolution-independence with the Voxel-size
Independent Neural Network framework, VINN. Here, we extend this concept by
additionally shifting all rigid-transforms into the network architecture with a
four degree of freedom (4-DOF) transform module, enabling resolution-aware
internal augmentations (VINNA). In this work we show that VINNA (i)
significantly outperforms state-of-the-art external augmentation approaches,
(ii) effectively addresses the head variations present specifically in newborn
datasets, and (iii) retains high segmentation accuracy across a range of
resolutions (0.5-1.0 mm). The 4-DOF transform module is a powerful, general
approach to implement spatial augmentation without requiring image or label
interpolation. The specific network application to newborns will be made
publicly available as VINNA4neonates.Comment: Under Review at Imaging Neuroscienc
A theoretical model of Polycomb/Trithorax action unites stable epigenetic memory and dynamic regulation
Polycomb and Trithorax group proteins maintain stable epigenetic memory of gene expression states for some genes, but many targets show highly dynamic regulation. Here we combine experiment and theory to examine the mechanistic basis of these different modes of regulation. We present a mathematical model comprising a Polycomb/Trithorax response element (PRE/TRE) coupled to a promoter and including Drosophila developmental timing. The model accurately recapitulates published studies of PRE/TRE mediated epigenetic memory of both silencing and activation. With minimal parameter changes, the same model can also recapitulate experimental data for a different PRE/TRE that allows dynamic regulation of its target gene. The model predicts that both cell cycle length and PRE/TRE identity are critical for determining whether the system gives stable memory or dynamic regulation. Our work provides a simple unifying framework for a rich repertoire of PRE/TRE functions, and thus provides insights into genome-wide Polycomb/Trithorax regulation.Peer Reviewe
Fostering learning goals at work: the interplay of dispositional and workplace learning goal orientation and supervisor appraisal behavior
A workplace that emphasizes personal learning and task mastery fosters employee development and performance. However, it is yet unclear which specific factors support such a learning goal-oriented workplace. Based on research in the educational domain, we investigated the reciprocal effects of dispositional learning goal orientation, supervisor’s appraisal behavior, and a learning goal-oriented workplace. In a study with a repeated measurement design (N = 144 employees), we did not find support for an effect of supervisor’s appraisal behavior (operationalized by the perceived use of self-reference norms and constructive handling of errors by employees) on workplace learning goal orientation over time. However, we found that a dispositional learning goal orientation of employees supports a learning goal-oriented work environment. Furthermore, workplace learning goal orientation had a cross-lagged effect on dispositional learning goal orientation and supervisor’s appraisal behavior. By comparing our results from work to findings from the educational context, our results convey important theoretical implications about the construct of workplace goal orientation and suggest practical applications to foster a learning goal-oriented workplace in terms of personnel development and performance management
Computational Design and Characterisation of Gyroid Structures with Different Gradient Functions for Porosity Adjustment
Triply periodic minimal surface (TPMS) structures have a very good lightweight potential, due to their surface-to-volume ratio, and thus are contents of various applications and research areas, such as tissue engineering, crash structures, or heat exchangers. While TPMS structures with a uniform porosity or a linear gradient have been considered in the literature, this paper focuses on the investigation of the mechanical properties of gyroid structures with non-linear porosity gradients. For the realisation of the different porosity gradients, an algorithm is introduced that allows the porosity to be adjusted by definable functions. A parametric study is performed on the resulting gyroid structures by performing mechanical simulations in the linear deformation regime. The transformation into dimensionless parameters enables material-independent statements, which is possible due to linearity. Thus, the effective elastic behaviour depends only on the structure geometry. As a result, by introducing non-linear gradient functions and varying the density of the structure over the entire volume, specific strengths can be generated in certain areas of interest. A computational design of porosity enables an accelerated application-specific structure development in the field of engineering
Wie viel sollten Mütter und Väter arbeiten? Idealvorstellungen variieren in und nach der Rushhour des Lebens
Der Artikel betrachtet die Rushhour des Lebens, die durch die Doppelbelastung aus Familien- und Erwerbsarbeit für Mütter und Väter insbesondere in der Lebensphase mit kleinen Kindern entsteht. Basierend auf Daten des familiendemografischen Panels FReDA wird gezeigt, dass die von den Befragten als ideal angesehene Erwerbsarbeitszeit für Mütter mit Kindern im Alter von 4 bis 18 Jahren deutlich höher ist als deren tatsächliche Arbeitszeit. Für Väter dagegen werden geringere Erwerbsarbeitszeiten als die tatsächlich von ihnen geleisteten als ideal angesehen, vor allem mit jungen Kindern. Die Studienergebnisse haben familienpolitische und arbeitsmarktbezogene Relevanz, auch vor dem Hintergrund des Arbeitskräftemangels. Mütter könnten durch Politik und Arbeitgebende eine stärkere Unterstützung bei der schrittweisen Erhöhung ihrer Arbeitszeit mit zunehmendem Alter der Kinder erfahren. Während für Väter in der Rushhour des Lebens die Realisierung einer vollzeitnahen Teilzeit hilfreich wäre
Thermoanalytical Investigations on the Influence of Storage Time in Water of Resin-Based CAD/CAM Materials
New resin-based composites and resin-infiltrated ceramics are used to fabricate computer-aided design (CAD) and computer-aided manufacturing (CAM)-based restorations, although little information is available on the long-term performance of these materials. The aim of this investigation was to determine the effects of storage time (24 h, 90 days, 180 days) on the thermophysical properties of resin-based CAD/CAM materials. Thermogravimetric Analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used in the study. TGA provided insight into the composition of the resin-based materials and the influence of internal plasticization and water sorption. Resin-based composites showed different decomposition, heat energy and mechanical behavior, which was influenced by storage time in water. Individual materials such as Grandio bloc showed lower influence of water storage while maintaining good mechanical properties
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