The 1932 Kem Lec Mek

This is a digitized, downloadable version of the Newark College of Engineering Nucleus.https://digitalcommons.njit.edu/yearbooks/1063/thumbnail.jp

3D Quantification and Description of the Developing Zebrafish Cranial Vasculature

Background: Zebrafish are an excellent model to study cardiovascular development and disease. Transgenic reporter lines and state-of-the-art microscopy allow 3D visualization of the vasculature in vivo. Previous studies relied on subjective visual interpretation of vascular topology without objective quantification. Thus, there is the need to develop analysis approaches that model and quantify the zebrafish vasculature to understand the effect of development, genetic manipulation or drug treatment. Aim: To establish an image analysis pipeline to extract quantitative 3D parameters describing the shape and topology of the zebrafish vasculature, and examine how these are impacted during development, disease, and by chemicals. Methods: Experiments were performed in zebrafish embryos, conforming with UK Home Office regulations. Image acquisition of transgenic zebrafish was performed using a Z.1 Zeiss light-sheet fluorescence microscope. Pre-processing, enhancement, registration, segmentation, and quantification methods were developed and optimised using open-source software, Fiji (Fiji 1.51p; National Institutes of Health, Bethesda, USA). Results: Motion correction was successfully applied using Scale Invariant Feature Transform (SIFT), and vascular enhancement based on vessel tubularity (Sato filter) exceeded general filter outcomes. Following evaluation and optimisation of a variety of segmentation methods, intensity-based segmentation (Otsu thresholding) was found to deliver the most reliable segmentation, allowing 3D vascular volume measurement. Following successful segmentation of the cerebral vasculature, a workflow to quantify left-right intra-sample symmetry was developed, finding no difference from 2-to-5dpf. Next, the first vascular inter-sample registration using a manual landmark-based approach was developed and it was found that conjugate direction search allowed automatic inter-sample registration. This enabled extraction of age-specific regions of similarity and variability between different individual embryos from 2-to-5dpf. A workflow was developed to quantify vascular network length, branching points, diameter, and complexity, showing reductions in zebrafish without blood flow. Also, I discovered and characterised a previously undescribed endothelial cell membrane behaviour termed kugeln. Conclusion: A workflow that successfully extracts the zebrafish vasculature and enables detailed quantification of a wide variety of vascular parameters was developed

AN INVESTIGATION INTO THE DEVELOPMENT OF ENGINEERING STUDENTS' CONCEPTUAL UNDERSTANDING OF MATHEMATICS

Following widespread concern over an apparent decline in the mathematical skills of engineering students, this study employed survey and observation methods to investigate the ways in which engineering students understand mathematical concepts, and to compare these with the concepts held-by students of mathematics. It was found that the engineering students employ a different vocabulary from mathematics students in discussing mathematics, and that their understanding of mathematical concepts develops differently from mathematics students both in response to teaching (which appears to be a transitory effect) and as their experience gives meaning to the ideas in life outside study. These findings are important in two ways. We need to make the mathematics teachers of engineering students aware of the language and concepts of their students so that the possibility of mutual misunderstanding is reduced, and we as educators need to help engineering students to make these connections in order to ground their mathematics in reality and to use mathematics an Instrument for understanding the world. Compared with the classical mathematical modelling paradigm and the classical empirical modelling paradigm, the method used by engineering students was found to be a hybrid based on the Identification of the type of problem and the application of a "preexisting law. Some misconceptions concerning the behaviour of beams In bending were found to be widely held, by respondents with a range of levels of experience. Whereas the particular misconceptions are not Important in themselves. It Is salutary to realise that expertise in one area of study does not necessarily Inoculate one against misconceptions In a closely related area. A software package was written using the context of mathematical modelling to help students relate concepts In calculus to physical situations. This package was found not to engage the students sufficiently to provoke cognitive change, and suggests that a higher degree of Interactivity Is needed

Characterising dust emission events from long-term surface observations in northern Africa

Dust plays multiple important roles in the Earth system with emissions from northern Africa contributing on the order of 60% to the global total. Current model estimates of annual dust production from this crucial region vary by a factor of up to 5. This low agreement between models is to a great extent due to differences in the representation of near-surface winds. One barrier to better understanding of wind processes is the sparse observation network in northern Africa combined with regionally varying, but not necessarily documented, reporting procedures that lead to uncertainties and biases. Previous studies have utilised long-term station observations of visibility over this region to investigate dust climatology, but this work is the first to focus specifically on emission, based on quality-controlled reports from station observers and measurements of 10 m wind-speed. The interannual, seasonal and diurnal cycles of dust emission frequency (FDE), as well as trends, are investigated using existing and new analysis methods, such as the estimation of emission thresholds. Spatially, it is shown that threshold wind-speeds for dust emission are highest in northern Algeria and lowest in Sudan and around the latitude band 16◦N - 21◦N. FDE peaks in spring at most stations, while in the Sahel seasonal cycles vary between stations depending on their proximity to the Saharan Heat Low, and as a result of seasonal exposure to both the summer monsoon and winter Harmattan. Seasonally, FDE is largely controlled by changes in strong winds, rather than changes in emission thresholds. The relative contribution of different wind-speeds to dust uplift are investigated using the observed winds and calculated thresholds. Case studies and field campaign data are analysed to determine the plausibility of SYNOP high-wind reports. In northern regions, 50% of uplift is associated with high winds which occur only 0.3% - 0.5% of the time. This contrasts with an occurrence range of 0.7% - 2.5% for southern regions. Winds of 12 – 15 ms−1 contribute the most to northern total DUP, while in the south the range is lower at 7-11 ms−1. A percentage occurrence of 0.3% equates to only 5.5 events per year. Previous studies have documented changes in the dust output from northern Africa on interannual to decadal time scales, though the reasons for this variability are still debated. This study shows that the likely contributors to an observed decreasing trend in FDE are changes in circulation patterns, changes to the Bowen ratio and, most significantly, the effect of a change in roughness on wind-speed as a result of a greening of the Sahel. This work forms a base for further investigations into mechanisms for dust emission in northern Africa and their relative importance, as well as providing reference material for model and reanalysis evaluation

Proceedings of the Sixth Hydraulics Conference

https://ir.uiowa.edu/uisie/1036/thumbnail.jp

AN INVESTIGATION OF LOWER SECONDARY PUPILS' IMAGES OF MATHEMATICS AND MATHEMATICIANS

This thesis reports on a three-part research project in which the images of mathematics and mathematicians held by lower secondary pupils were investigated. A survey tool which asked pupils to draw a picture of a mathematician at work, and which included a Likert-type scale and open-ended writing prompts, was designed and developed for use in an international study of pupils in five countries (n = 476). The results indicate that while some pupils hold stereotypical images in common, all pupils appear to know very little about mathematicians and the work they do. Mathematicians' invisibility to pupils of this age appears to affect their images of mathematics. The tool was refined and utilised again as part of two interventions in the United States: the first attempted to see if images would be affected by a unit in graph theory and discrete mathematics topics (n = 28); the second brought pupils (n = 174) together with a panel of mathematicians. Each intervention had different strengths, but both widened pupils' views of mathematics, enabling them to see it as more than just a study of numbers. In a third small study, professionals in the mathematics field (n = 106) from ten countries were asked in a short survey to comment on Who is a mathematician? and Who may call oneself one? Findings of this portion of the study indicate a lack of a unified vision among members of the mathematics community and some evidence of an elitism which would restrict who may define themselves as a mathematician

Milestone - 1972

https://encompass.eku.edu/yearbooks/1055/thumbnail.jp