Letter From the Editor

http://deepblue.lib.umich.edu/bitstream/2027.42/120302/1/Markiewicz_LetterFromTheEditor.pd

Optimizing the Transportation of Potable Water to Kaura- Namoda and Its Surrounding Villages

The importance of potable water in life can never be over – emphasized. In this research paper, the transportation of potable water to Kaura – Namoda and its surrounding villages was optimized. Vogel’s approximation method in Tora software package was used. The minimum cost of transporting potable water from two treatment plants to 9 different communities (11 reservoirs) was obtained. It was found that the total required water consumption per person per day of the communities is 12,212,796 liters. An optimal value of N223, 662.39k was obtained in transporting the required quantities of water to all the communities every day. Keywords: Optimization, Transportation, Transshipment, Potable wate

What About the Children? - FDA's Response to Pediatric Drug Testing

The Federal Food and Drug Administration (FDA) has played a critical role in the protection of human subjects in research. Most recently, FDA enacted an interim final rule regarding protection of children in clinical investigations. FDA’s interim rule represents its most current policy on human subject protection. Current events illuminate FDA’s policies and how FDA has chosen to respond to debates over pediatric drug testing. This paper will provide a brief history of FDA’s participation in human subject protection. This paper will then focus on FDA’s policies for pediatric research, its interim rule, and how the interim rule relates to current events. Finally, this paper will make a comment about how FDA balances its competing duties of protecting the public but also of promoting research

Basal-plane growth of cadmium arsenide by molecular beam epitaxy

(001)-oriented thin films of the three-dimensional Dirac semimetal cadmium arsenide can realize a quantum spin Hall insulator and other kinds of topological physics, all within the flexible architecture of epitaxial heterostructures. Here, we report a method for growing (001) cadmium arsenide films using molecular beam epitaxy. The introduction of a thin indium arsenide wetting layer improves surface morphology and structural characteristics, as measured by x-ray diffraction and reflectivity, atomic force microscopy, and scanning transmission electron microscopy. The electron mobility of 50-nm-thick films is found to be 9300 cm2/Vs at 2 K, comparable to the highest-quality films grown in the conventional (112) orientation. This work demonstrates a simple experimental framework for exploring topological phases that are predicted to exist in proximity to the three-dimensional Dirac semimetal phase

Literacy as Tardis: Stories in Time and Space

Background/Context: This paper draws on previous work about narrative which regards the practice of storying our lives as a basic human impulse and one which draws on cultural resources to do so. Neophyte digital resources have fascinated and enticed us as devices to immerse ourselves ever deeply and widely to create shinier, polished narratives. Our new modes and media have impacted on the nature of our narratives and we reflect on our lives as we read them back to ourselves. Yet the affordances of the devices have allowed us to play also with the modes of time and space. This paper draws on theories suggested by Burnett et. al (2014), Leander and Sheehy (2004), Massey (2005) and Lemke (2000) to unpack the slippery nature of these notions of space and time. Purpose/Objective/Research: The article provides a series of examples from a range of scenarios and research projects to consolidate the proposal that the contexts of literacy events are difficult to delineate; that contexts slip and slide across space and time in ways that seem to defy absolute specificity – that they are ‘in motion’, mercurial and subject to change. Nevertheless, within these uncertain spaces, individuals use the cultural resources at their disposal to make sense of who they are and what the world is, through the creation of stories. Research Design: This is an analytical essay, which draws on the research of others to create a series of examples of ‘digital encounters.’ Conclusions/Recommendations: The paper argues that despite the many changes that digital tools have brought to our lives, the narrative impulse and the desire to represent ourselves through images and other media, has remained constant. The new tools seem to allow us however, to play more explicitly with time and space and to incorporate these aspects into our meaning making practices. We can use tools to explore new types of space and arenas for communication – not just because of our capacity to keep in touch across time and space (which is not new), but because we can disrupt how we perceive these concepts

Point group symmetry of cadmium arsenide thin films determined by convergent beam electron diffraction

Cadmium arsenide (Cd3As2) is one of the first materials to be discovered to belong to the class of three-dimensional topological semimetals. Reported room temperature crystal structures of Cd3As2 reported differ subtly in the way the Cd vacancies are arranged within its antifluorite-derived structure, which determines if an inversion center is present and if Cd3As2 is a Dirac or Weyl semimetal. Here, we apply convergent beam electron diffraction (CBED) to determine the point group of Cd3As2 thin films grown by molecular beam epitaxy. Using CBED patterns from multiple zone axes, high-angle annular dark-field images acquired in scanning transmission electron microscopy, and Bloch wave simulations, we show that Cd3As2 belongs to the tetragonal 4/mmm point group, which is centrosymmetric. The results show that CBED can distinguish very subtle differences in the crystal structure of a topological semimetal, a capability that will be useful for designing materials and thin film heterostructures with topological states that depend on the presence of certain crystal symmetries.Comment: Accepted for publication in Physical Review Material