Do Engineering Students Learn Ethics From an Ethics Course?

The goal of the present research is to develop machine-assisted methods that can assist in the analysis of students’ written compositions in ethics courses. As part of this research, we analyzed Social Impact Assessment (SIA) papers submitted by engineering undergraduates in a course on engineering ethics. The SIA papers required students to identify and discuss a contemporary engineering technology (e.g., autonomous tractor trailers) and to explicitly discuss the ethical issues involved in that technology. Here we describe the ability of three machine tools to discriminate differences in the technical compared to ethical portions of the SIA papers. First, using LIWC (Language Inquiry and Word Count) we quantified differences in analytical thinking, expertise and self-confidence, disclosure, and affect, in the technical and ethical portions of the papers. Next, we applied MEH (Meaning Extraction Helper) to examine differences in critical concepts in the technical and ethical portions of the papers. Finally, we used LDA (Latent Dirichlet Allocation) to examine differences in the topics in the technical and ethical portions of the papers. The results of these three tests demonstrate the ability of machine-based tools to discriminate conceptual, affective, and motivational differences in the texts that students compose that relate to engineering technology and to engineering ethics. We discuss the utility and future directions for this research.Cockrell School of Engineerin

Analysis of Carrier Recombination Processes in 0.6 eV InGaAs Epitaxial Materials for Thermophotovoltaic Devices

Minority carrier lifetime was measured by time-resolved photoluminescence (TRPL) method in sets of p-type and n-type InGaAs double heterostructures (DH) moderately doped with Zn and Te, respectively. Contributions of the radiative and non-radiative recombination terms were separated by fitting experimental data to temperature dependences of the radiative term. The latter was modeled with measured fundamental absorption spectrum and the temperature dependence of the photon recycling effect was taken into account. Different temperature dependences of radiative terms for electron and hole materials were obtained. It was concluded that in 0.6 eV Te-doped InGaAs structures the radiative recombination controls the hole lifetime at liquid nitrogen temperatures, while Auger recombination dominates at room and above room temperatures. In similar 0.6 eV InGaAs with Zn-doped active regions Shockley-Read-Hall (SRH) recombination was found dominant in a wide temperature range from liquid nitrogen to above-room temperatures. Rapid decrease of electron lifetime with decrease of excess carrier concentration was observed and attributed to recombination through partially-ionized deep donor centers. The obtained data allows for more adequate modeling of the performance and design optimization of narrow-gap photonic devices based on InGaAs Indium-rich compounds

Microtubule-associated protein 1B: a neuronal binding partner for myelin-associated glycoprotein

Myelin-associated glycoprotein (MAG) is expressed in periaxonal membranes of myelinating glia where it is believed to function in glia–axon interactions by binding to a component of the axolemma. Experiments involving Western blot overlay and coimmunoprecipitation demonstrated that MAG binds to a phosphorylated neuronal isoform of microtubule-associated protein 1B (MAP1B) expressed in dorsal root ganglion neurons (DRGNs) and axolemma-enriched fractions from myelinated axons of brain, but not to the isoform of MAP1B expressed by glial cells. The expression of some MAP1B as a neuronal plasma membrane glycoprotein (Tanner, S.L., R. Franzen, H. Jaffe, and R.H. Quarles. 2000. J. Neurochem. 75:553–562.), further documented here by its immunostaining without cell permeabilization, is consistent with it being a binding partner for MAG on the axonal surface. Binding sites for a MAG-Fc chimera on DRGNs colocalized with MAP1B on neuronal varicosities, and MAG and MAP1B also colocalized in the periaxonal region of myelinated axons. In addition, expression of the phosphorylated isoform of MAP1B was increased significantly when DRGNs were cocultured with MAG-transfected COS cells. The interaction of MAG with MAP1B is relevant to the known role of MAG in affecting the cytoskeletal structure and stability of myelinated axons

Adoption of improved cowpea (Vigna unguiculata (L.) Walp) technologies in Ghana

The Ghana Grains Development Project has developed and disseminated improved cowpea production technologies to farmers in Ghana since 1985. These technologies were improved varieties, row planting, and the use of pre- and post-flowering insecticides. To assess the extent of adoption of these technologies by farmers, eight cowpea production districts were surveyed across four agro-ecological zones in 1995 in Ghana. A random sample of 313 cowpea farmers participated in the survey. Results indicated that 70 per cent used recommended pre-flowering insecticides, and 26 per cent adopted post-flowering insecticides across the ecological zones. The highest adoption rate for improved varieties was observed in the Forest Zone (97 %). The adoption of row planting was highest in the Forest Zone (100 %), followed by the Guinea Savanna Zone (92 %), and lowest in the Coastal Savanna Zone (58 %). Most farmers agreed that by adopting improved production technologies, their yields and overall production increased, and they made more profit from cowpea cultivation.The whole family participates in various activities associated with cowpea production. However, men do strenuous work like land preparation, weeding and spraying of insecticides, while women and children participate in less strenuous work such as planting, harvesting and threshing. Le Project de Développement des Grains du Ghana a developpé et disséminé les technologies de la production de dolique amélioré aux cultivateurs au Ghana depuis 1985. Ces technologies étaient les variétés améliorées, la culture en lignes et usage d'insecticides avant et après la floraison. Pour évaluer le degré d'adoption de ces technologies par les cultivateurs, un sondage a été entrepris en 1995 en 8 districts de production de dolique à travers quatre zones agro-écologique au Ghana. Un échantillon pris au hasard de 313 cultivateurs de dolique participaient au sondage. Les résultats indiquaient que 70% utilisaient les insecticides d'avant floraison recommandés et 26% adoptaient les insecticides d'après floraison à travers les zones écologiques. La proportion d'adoption la plus élevée pour les variétés améliorées était observée dans la zone forestière (97 %). L'adoption de la culture en lignes est la plus élevée dans la zone forestière (100 %) et suivi par la zone savane-guinéenne (92 %) et la plus faible dans la zone savane-littorale (58 %). La plupart de cultivateurs étaient du même avis que par l'adoption des technologies de production améliorée, leur rendements et la production globale augmentaient, et ils avaient tiré plus de bénéfice de la production de dolique. Toute la famille participent aux activités différentes liées à la production de dolique. Cependant le travail ardu tel que la préparation de terre, le désherbage et la pulvérisation d'insecticide sont faites par les hommes alors que les femmes et les enfants participent aux travaux moins ardus tels que la plantation, la moisson et la battage. Ghana Journal of Agricultural Science Vol. 39 (1) 2006: pp. 25-3

Development of a lightweight, light-trapped, thin GaAs solar cell for spacecraft applications

This paper describes ultra-lightweight, high performance, thin, light trapping GaAs solar cells for advanced space power systems. The device designs can achieve 24.5 percent efficiency at AMO and 1X conditions, corresponding to a power density of 330 W/m2. A significant breakthrough lies in the potential for a specific power of 2906 W/kg because the entire device is less than 1.5 microns thick. This represents a 440 percent improvement over conventional 4-mil silicon solar cells. In addition to being lightweight, this thin device design can result in increased radiation tolerance. The attachment of the cover glass support to the front surface has been demonstrated by both silicone and electrostatic bonding techniques. Device parameters of 1.002 volts open-circuit voltage, 80 percent fill factor, and a short-circuit current of 24.3 mA/sq cm have been obtained. This demonstrates a conversion efficiency of 14.4 percent resulting in a specific power of 2240 W/kg. Additionally, this new technology offers an alternative approach for enabling multi-bandgap solar cells and high output space solar power devices. The thin device structure can be applied to any 3-5 based solar cell application, yielding both an increase in specific power and radiation tolerance

Household hunger, poverty, and childcare in 5 states of Nigeria and their impacts on nutritional outcomes in preschool children

Open Access Article; Published online: 04 May 2021This article presents findings from baseline surveys in 5 states of Nigeria to assess the nutritional outcomes on target groups on attaining the UN Sustainable Development Goal 2. The augmented regression technique was applied to analyze data from a sample of 1642 households with at least 1 child under the age of 5 years (U5) and their mothers or caregivers out of a total of 2500 households that were drawn from the 250 enumeration areas of the Nigeria Bureau of Statistics in the 5 states. The results support the growing evidence base that poverty and household hunger are pervasive. The incidence of poverty highlights inequalities among states. The combination of poverty and hunger was mirrored in the damning extent to which all forms of malnutrition coexisted in children U5, particularly during the second year of infancy and among poor households. Evidence from this study points to poor dietary quality of complementary food rather than other childcare practices as majorly responsible for child malnutrition. Child wellness was positively affected by maternal health-seeking behavior but negatively by the poverty probability index of the household. Notably, maternal health-seeking behavior played a more relevant role in child wellness than mothers’ educational attainment

Entanglement swapping for generation of heralded time-frequency-entangled photon pairs

Photonic time-frequency entanglement is a promising resource for quantum information processing technologies. We investigate swapping of continuous-variable entanglement in the time-frequency degree of freedom using three-wave mixing in the low-gain regime with the aim of producing heralded biphoton states with high purity and low multi-pair probability. Heralding is achieved by combining one photon from each of two biphoton sources via sum-frequency generation to create a herald photon. We present a realistic model with pulsed pumps, investigate the effects of resolving the frequency of the herald photon, and find that frequency-resolving measurement of the herald photon is necessary to produce high-purity biphotons. We also find a trade-off between the rate of successful entanglement swapping and both the purity and quantified entanglement resource (negativity) of the heralded biphoton state.Comment: 17 pages and 9 figures. Version 3 corrects an error in the count rate theory and calculations, fixes a few grammatical and typographical errors, improves formatting, and adds the journal referenc

Ge quantum dot arrays grown by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface: nucleation, morphology and CMOS compatibility

Issues of morphology, nucleation and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (<600 deg C) and high (>600 deg. C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts---pyramids and wedges---are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.Comment: 30 pages, 11 figure