Impact of online learning on student effort and persistence in technical college students

Includes bibliographical references

Overtopping and breaching of dikes – Breach profile and breach flow

River hydrodynamicsUnsteady open channel flow and dam brea

Surgical probe and implant development for nucleus pulposus replacements

Intervertebral disc degeneration is a major reason why we experience low back pain. Intervertebral discs are located in-between the vertebrae of the spine. They act, among other, as shock absorbers by distributing the mechanical load applied to the spine while giving it its range of motion. An intervertebral disc is composed of a center - a soft core, called nucleus pulposus which is surrounded by a strong ring called the annulus fibrosus. By disc degeneration, we mean a physical deterioration of either the nucleus and/or the annulus. It has been posited that low back pain could be alleviated by replacing the degenerated nucleus pulposus by a synthetic implant. However, such nucleus pulposus replacements have been subjected to highly controversial discussions over the last 50 years and their use has not yet resulted in a positive outcome to treat degenerated disc disease. In this thesis, we report on the development of an implant material consisting of poly(ethylene glycol)dimetacrylate - a hydrogel - loaded with nano-fibrillated cellulose. Photopolymerization was selected as a polymerization method to "harden" the implant in situ. Thus, the implant can be injected in a liquid state through the annulus fiborsus with a small diameter cannula. Furthermore, an in situ photopolymerization method was developed along with an implanting device which was used to insert the composite hydrogel into an intervertebral disc ex vivo. The volume of a human nucleus pulposus is several 100 cubic millimeters, which is a substantial volume to photopolymerize. In order to ensure a homogeneous photopolymerization of this volume, a Monte Carlo model was developed. The model is able to predict accurately the volume of the photopolymerized implant in tissue cavities. This simulation tool was used to tailor the light scattering properties of the hydrogel by loading it with lipid particles. Thus, spherical implant shapes could be photopolymerized. An implanting device was developed to inject and photopolymerize the liquid implant while monitoring the cross-linking reaction of the implant during photopolymerization using fluorescence spectroscopy in situ and in real-time. Using this device, synthetic nucleus pulposus implants were successfully inserted through a 1 mm incision in the annulus fiborsus of an ex vivo bovine intervertebral disc model and the long-term performance of the proposed nucleus pulposus replacement was evaluated. The changes of the fluorescence signal throughout the photopolymerization reaction could be shown to correlate with the photopolymerization volume. It was thus possible to insert the synthetic implant in a controlled manner into the bovine disc model. The implant was able to significantly re-establish intervertebral disc height after surgery (p < 0.0025) and maintain it over 0.5 million loading cycles (p < 0.025). Disc height is one of the essential parameters to restore and maintain in an intervertebral disc. The excellent results achieved in these ex vivo experiments validated the implantation method and the device. More importantly, they showed that the novel implant material might resist mechanical loads similar to the loads that would be experienced in everyday life. However, longer tests (~ 10 million cycles) are required to determine whether this material would truly resists during a clinical study

Drift accumulation at river bridges

River hydrodynamicsInteraction with structure

Identifying runoff processes on the plot and catchment scale

International audienceRainfall-runoff models that adequately represent the real hydrological processes and that do not have to be calibrated, are needed in hydrology. Such a model would require information about the runoff processes occurring in a catchment and their spatial distribution. Therefore, the aim of this article is (1) to develop a methodology that allows the delineation of dominant runoff processes (DRP) in the field and with a GIS, and (2) to illustrate how such a map can be used in rainfall-runoff modelling. Soil properties were assessed of 44 soil profiles in two Swiss catchments. On some profiles, sprinkling experiments were performed and soil-water levels measured. With these data, the dominant runoff processes (DRP) were determined using the Scherrer and Naef (2003) process decision scheme. At the same time, a simplified method was developed to make it possible to determine the DRP only on the basis of maps of the soil, topography and geology. In 67% of the soil profiles, the two methods indicated the same processes; in 24% with minor deviations. By transforming the simplified method into a set of rules that could be introduced into a GIS, the distributions of the different DRPs in two catchments could be delineated automatically so that maps of the dominant runoff processes could be produced. These maps agreed well with manually derived maps and field observations. Flood-runoff volumes could be quite accurately predicted on the basis of the rainfall measured and information on the water retention capacity contained in the DRP map. This illustrates the potential of the DRP maps for defining the infiltration parameters used in rainfall-runoff models

Global universal approximation of functional input maps on weighted spaces

We introduce so-called functional input neural networks defined on a possibly infinite dimensional weighted space with values also in a possibly infinite dimensional output space. To this end, we use an additive family as hidden layer maps and a non-linear activation function applied to each hidden layer. Relying on Stone-Weierstrass theorems on weighted spaces, we can prove a global universal approximation result for generalizations of continuous functions going beyond the usual approximation on compact sets. This then applies in particular to approximation of (non-anticipative) path space functionals via functional input neural networks. As a further application of the weighted Stone-Weierstrass theorem we prove a global universal approximation result for linear functions of the signature. We also introduce the viewpoint of Gaussian process regression in this setting and show that the reproducing kernel Hilbert space of the signature kernels are Cameron-Martin spaces of certain Gaussian processes. This paves the way towards uncertainty quantification for signature kernel regression.Comment: 57 pages, 4 figure

Educating moral sensitivity in business: An experimental study to evaluate the effectiveness of a serious moral game

Serious games have emerged as a promising new form of education and training. Even though the benefits of serious games for education are undisputed, there is still a further need for research on the efficacy of such games. The main goal of our research is to examine the effectiveness of a serious moral game—uFin: The Challenge—that was designed to promote moral sensitivity in business, a precondition of ethical decision-making and behavior and a core moral competency of moral intelligence. A second goal is to examine the role of metacognitive prompting and prosocial nudging in influencing learning effectiveness. Participants (N = 345) took part in an experimental game-based intervention study and completed a pre- and post-test questionnaire assessing moral sensitivity. The analyses of both questionnaire and game data suggest that merely playing this game is effective in promoting moral sensitivity. Neither self-reflection nor exposure to prosocial nudges, however, were determined to be factors that improve learning effectiveness. In contrast, those interventions even decreased the learning outcome in some cases. Overall, findings demonstrate the potential for game-based learning in the moral domain. An important avenue for future research is to examine others ways of increasing the effectiveness of the game

Geometry- and load-specific optimization of the collagen network's fibre orientation in the lumbar spine's annulus fibrosus

In Europe, low back pain (LBP) affects the quality of life of up to 30% of the active population. Although the origin of LBP is not well identified and is probably not unique, epidemiological studies suggest that the severity of the disease is correlated with mechanical factors. The lumbar spine is a complex structure where bone, cartilage, ligaments, and muscles have specific and functional mechanical interactions that depend on the shape and structure of each tissue. Thus, any local tissue abnormality may generate non-physiological loadings on surrounding tissues, extending or catalysing a pre-existing degenerative process. To date, lumbar spine finite element modelling is one of the most promising methods to thoroughly investigate functional load transfers between the different spine tissues. However, many geometrical or mechanical parameters used for tissue modelling are still not quantified and need to be assumed. Previous computational studies demonstrated that the intervertebral disc (IVD) plays a key role in distributing the internal forces across the lumbar spine structure. Within the IVD, together with the nucleus pulposus (NP) pressure, the annulus fibrosus (AF) collagen organization is one of the most influential parameter for the disc stabilization. However, AF collagen organization is not unique and seems to depend on the particularity of spine morphologies. Therefore, any lumbar spine model based on particular geometrical data would require specific definitions of fibre-induced AF anisotropy. Unfortunately, particular AF anisotropies are hardly measurable. Thus, the present project aims to investigate the stabilization of a L4-L5 lumbar spine bi-segment finite element model as a function of the AF fibre orientations. For this, a mathematical function, based on local AF matrix shear strains, fibre stresses and fibre stress distribution has been proposed. In this function was implemented and was partially validated on smaller AF model. Enhancements could be proposed and be applied to the L4-L5 model. Methods and procedure to optimize annulus AF orientations could be validated. The proposed evaluation function had to be changed. It was found that an optimal orientation depends mainly on fibre stress and matrix shear stress. The optimizations converged to average angles between 32 and 68 and radial gradients between 10 and 17 degree. Tangential gradients could not be found. Moreover a critical fibre angle could be determined where fibre under uni-axial load are not loaded any more. Using literature data it was possible to solve one of the main issues of collagen fibre orientations in the AF and to bring together the two hypothesis of either a only radial or only a tangential gradient. Moreover it was concluded that pre-stress respectively hoop stress is an nonnegligible factor which has to be accounted for in IVD finite element models

Moral sensitivity in business: A revised measure

In order to manage ethical challenges in organizations and the workplace, moral sensitivity (MS)—the ability to identify and ascribe importance to moral issues when they arise in the workplace—is seen as the key prerequisite by researchers and professionals. However, despite the importance of MS, satisfactory reliable and valid measures to assess this competence are to date lacking. The present research tests the psychometric qualities of a revised MS measure for the business domain (R-MSB) that is designed to assess individual differences in moral and business-related value sensitivity. We present three different analyses with two heterogeneous samples of Swiss and German employees (total N = 1168). The first two studies provide good evidence of the measures’ factorial structure, its construct, and criteria-related validity. The third study examines how affective and empathic responses are associated with MS and business sensitivity (BS). The results support the view that empathic responsiveness enhances MS. The instrument’s theoretical and practical strengths, limitations, and avenues for future research are discussed