North Carolina State University

About: North Carolina State University is a education organization based out in Raleigh, North Carolina, United States. It is known for research contribution in the topics: Population & Thin film. The organization has 44161 authors who have published 101744 publications receiving 3456774 citations. The organization is also known as: NCSU & North Carolina State University at Raleigh.

Exposure to bisphenol A advances puberty

Abstract: Plastics and pesticides are examples of products that contain oestrogenic endocrine-disrupting chemicals, or EEDCs, which can interfere with mammalian development by mimicking the action of the sex hormone oestradiol1. For instance, the exposure of developing rodents to high doses of EEDCs advances puberty and alters their reproductive function2. Low environmental doses of EEDCs may also affect development in humans3. Effects have become apparent in humans over the past half century that are consistent with those seen in animals after exposure to high doses of EEDCs, such as an increase in genital abnormality in boys4 and earlier sexual maturation in girls5. Here we show that exposing female mouse fetuses to an EEDC at a dose that is within the range typical of the environmental exposure of humans alters the postnatal growth rate and brings on early puberty in these mice.

Designing and Teaching Courses to Satisfy the ABET Engineering Criteria

Abstract: Since the new ABET accreditation system was first introduced to American engineering education in the middle 1990s as Engineering Criteria 2000, most discussion in the literature has focused on how to assess Outcomes 3a-3k and relatively little has concerned how to equip students with the skills and attitudes specified in those outcomes. This paper seeks to fill this gap. Its goals are to (1) overview the accreditation process and clarify the confusing array of terms associated with it (objectives, outcomes, outcome indicators, etc.); (2) provide guidance on the formulation of course learning objectives and assessment methods that address Outcomes 3a-3k; (3) identify and describe instructional techniques that should effectively prepare students to achieve those outcomes by the time they graduate; and (4) propose a strategy for integrating program-level and course-level activities when designing an instructional program to meet the requirements of the ABET engineering criteria.

Identification and Review of Sensitivity Analysis Methods

Abstract: Identification and qualitative comparison of sensitivity analysis methods that have been used across various disciplines, and that merit consideration for application to food-safety risk assessment models, are presented in this article. Sensitivity analysis can help in identifying critical control points, prioritizing additional data collection or research, and verifying and validating a model. Ten sensitivity analysis methods, including four mathematical methods, five statistical methods, and one graphical method, are identified. The selected methods are compared on the basis of their applicability to different types of models, computational issues such as initial data requirement and complexity of their application, representation of the sensitivity, and the specific uses of these methods. Applications of these methods are illustrated with examples from various fields. No one method is clearly best for food-safety risk models. In general, use of two or more methods, preferably with dissimilar theoretical foundations, may be needed to increase confidence in the ranking of key inputs.

Strain-related phenomena in GaN thin films

Abstract: Photoluminescence (PL), Raman spectroscopy, and x-ray diffraction are employed to demonstrate the co-existence of a biaxial and a hydrostatic strain that can be present in GaN thin films. The biaxial strain originates from growth on lattice-mismatched substrates and from post-growth cooling. An additional hydrostatic strain is shown to be introduced by the presence of point defects. A consistent description of the experimental results is derived within the limits of the linear and isotropic elastic theory using a Poisson ratio $\ensuremath{ u}=0.23\ifmmode\pm\else\textpm\fi{}0.06$ and a bulk modulus $B=200\ifmmode\pm\else\textpm\fi{}20$ GPa. These isotropic elastic constants help to judge the validity of published anisotropic elastic constants that vary greatly. Calibration constants for strain-induced shifts of the near-band-edge PL lines with respect to the ${E}_{2}$ Raman mode are given for strain-free, biaxially strained, and hydrostatically contracted or expanded thin films. They allow us to extract differences between hydrostatic and biaxial stress components if present. In particular, we determine that a biaxial stress of one GPa would shift the near-band-edge PL lines by 27\ifmmode\pm\else\textpm\fi{}2 meV and the ${E}_{2}$ Raman mode by 4.2\ifmmode\pm\else\textpm\fi{}0.3 ${\mathrm{cm}}^{\ensuremath{-}1}$ by use of the listed isotropic elastic constants. It is expected from the analyses that stoichiometric variations in the GaN thin films together with the design of specific buffer layers can be utilized to strain engineer the material to an extent that greatly exceeds the possibilities known from other semiconductor systems because of the largely different covalent radii of the Ga and the N atom.

Generalized Hypercube and Hyperbus Structures for a Computer Network

Abstract: A general class of hypercube structures is presented in this paper for interconnecting a network of microcomputers in parallel and distributed environments. The interconnection is based on a mixed radix number system and the technique results in a variety of hypercube structures for a given number of processors N, depending on the desired diameter of the network. A cost optimal realization is obtained through a process of discrete optimization. The performance of such a structure is compared to that of other existing hypercube structures such as Boolean n-cube and nearest neighbor mesh computers.