3D Imaging of Gems and Minerals by Multiphoton Microscopy

Many optical approaches have been used to examine the composition and structure of gemstones, both recently and throughout history. The nonlinear optical behavior of different gemstones has not been investigated, and the higher order terms to the refractive index represent an unused tool for qualifying and examining a stone. We have used a multiphoton microscope to examine the nonlinear optical properties of 36 different gemstones and demonstrate that it is a useful tool for imaging them three-dimensionally up to the millimeter scale below the sample surface. The polarization dependence of second harmonic generation signals was used to examine the crystal orientations inside the minerals.Comment: 9 pages, five figure

Perceptions of Adaptive Technology Usage in Secondary Math Classrooms

Adaptive learning is an emerging technology in education that teachers use to instruct, reinforce, and assess student performance (Smith, 2016). Adaptive technology is powerful because it gives teachers an opportunity to differentiate based on individual needs (Bilous, 2019). It is efficient, allows students to get instant feedback, and can improve the learning experience for students (Matherson & Windle, 2017). Like many other technologies, it is constantly evolving; this makes it difficult to research and update curriculum because programs are constantly changing (Parsons, 2014). With these changes, teachers are also required to update how they manage their classroom and how they deliver instruction. Students are no longer expected to “sit and get”, a term used for when teachers lecture to uninterested or disengaged pupils (McLeskey & Waldron, 2002). Lecture-based learning is no longer seen as an effective method for teaching children (McLeskey & Waldron, 2002). Instead, students are given more autonomy and teachers are expected to deliver lessons that are interactive, engaging, and impactful (Matherson & Windle, 2017). EdTechXGlobal estimated that $252 billion would be spent on education technology by 2020 (EdTechXGlobal, 2016). School leaders believe in investing in technology; however, research suggests that simply investing in software and smart devices is not enough (Zhu, Yu, & Riezebos, 2016). Teachers must also know how to use the tools effectively. Students must buy into the concept of computer-based curriculum. Based on the results of this study, there is plenty of room for growth in this educational technology and adaptive learning. Prior to this study, there was little empirical research to address adaptive technology, specifically. Without that research, there are simply too many questions that have not been answered about how adaptive technology impacts the classroom. This dissertation sought to provide a current snapshot into adaptive technology, the benefits of using it, and the challenges teachers and students currently face in using it

Food for Thought: Genetically Modified Seeds as De Facto Standard Essential Patents

For several years, courts have been improperly calculating damages in cases involving the unlicensed use of genetically-modified (GM) seed technology. In particular, when courts determine patent damages based on the hypothetical negotiation method, they err in exaggerating these damages to a point where no rational negotiator would agree. In response, we propose a limited affirmative defense of an implied license due to the patent’s status as a de facto standard essential patent. To be classified as a de facto standard essential patent, the farmer must prove three elements that reflect the peculiarities of GM seeds used in farming: (1) dominance, (2) impracticability, and (3) necessary to fulfill a basic need. Based on the approaches used by courts and standard setting organizations in licensing standard essential patents in technological fields such as cell phones and software, designation of some GM seeds as standard essential patents allows the courts to imply a license from patentees to farmers on reasonable and non-discriminatory (RAND) terms. Doing so shifts the case from a tort-based patent infringement suit to a breach of contract dispute and alters the damages regime from one based in compensation, deterrence, and punishment (a tort approach) to one based solely in compensation (a contractual approach). As a result of this novel proposal, the damages calculations in these suits return to economic reality

Simulation-Based Assessment of a Full-Scale Installed Quiet Landing Gear

Full-scale simulations of a Gulfstream G-III aircraft, performed in support of the NASA Acoustic Research Measurements flights, are presented to complement results discussed in earlier studies. The flow solver employed in those studies, Dassault Systmes lattice Boltzmann PowerFLOW, was also used during this investigation to conduct time-dependent simulations of the entire aircraft in landing configuration with a fully dressed landing gear. The high-fidelity simulations, performed at a Mach number of 0.23 and a Reynolds number of 10.5 106 based on mean aerodynamic chord, captured all relevant airframe noise sources. The computations were used to assess the aeroacoustic performance of the main landing gear, with and without noise reduction fairings installed, of a G-III aircraft equipped with Adaptive Compliant Trailing Edge technology and conventional Fowler flaps. To facilitate comparison of predicted noise signatures with effective perceived noise levels obtained from flight test measurements, the as-flown nose landing gear geometry, missing in our earlier studies, was added to the simulated G-III aircraft configurations. The high fidelity, synthetic data were post-processed using a Ffowcs-Williams and Hawkings integral approach to estimate farfield acoustic behavior, with pressures on the model solid surface or pressure and velocity components on a permeable surface enveloping the acoustic near field used as input

Linear Self-Motion Cues Support the Spatial Distribution and Stability of Hippocampal Place Cells

The vestibular system provides a crucial component of place-cell and head-direction cell activity [1-7]. Otolith signals are necessary for head-direction signal stability and associated behavior [8, 9], and the head-direction signal's contribution to parahippocampal spatial representations [10-14] suggests that place cells may also require otolithic information. Here, we demonstrate that self-movement information from the otolith organs is necessary for the development of stable place fields within and across sessions. Place cells in otoconia-deficient tilted mice showed reduced spatial coherence and formed place fields that were located closer to environmental boundaries, relative to those of control mice. These differences reveal an important otolithic contribution to place-cell functioning and provide insight into the cognitive deficits associated with otolith dysfunction

The Introduction of Bitcoin Futures: An Examination of Volatility and Potential Spillover Effects

Theory in Stein (1987) suggests that introducing derivative contracts, such as futures, can destabilize underlying asset prices if the contracts attract enough speculative traders. This paper examines how the introduction of Bitcoin futures influences the underlying Bitcoin market. Consistent with Stein (1987), we find that that Bitcoin\u27s volatility increases significantly during the post-introduction period. Perhaps more importantly, however, we observe significant spillover effects into related markets. For instance, in other cryptocurrencies, the increase in volatility in these markets is greater than the post-introduction increase in Bitcoin

The Information Content of Option Ratios

A broad stream of research shows that information flows into underlying stock prices through the options market. For instance, prior research shows that both the Put–Call Ratio (P/C) and the Option-to-Stock Volume Ratio (O/S) predict negative future stock returns. In this paper, we compare the level of information contained in these two commonly used option volume ratios. First, we find that P/C ratios contain more predictability about future stock returns at the daily level than O/S ratios. Second, in contrast to our first set of results, O/S ratios contain more predictability about future returns at the weekly and monthly levels than P/C ratios. In fact, our tests show that while P/C ratios contain predictability about future daily returns and, to some extent, future weekly returns, the return predictability in P/C ratios is fleeting. O/S ratios, on the other hand, significantly predict negative returns at all levels: daily, weekly, and monthly. While Pan and Poteshman (2006) show that signed P/C ratios, which require proprietary data, have predictive power, we find that unsigned P/C ratios, which do not require proprietary data, also have predictive power

Comovement in the Cryptocurrency Market

This study examines the comovement between 17 of the most active cryptocurrencies. We are unable to statistically reject the presence of perfect comovement between Bitcoin and six of the 16 non-Bitcoin cryptocurrencies. Consistent with the friction-based explanation for the presence of comovement, once the CBOE introduced futures contracts on Bitcoin, we find that all 16 cryptocurrencies comove with Bitcoin. These results suggest that introducing futures contracts improves the informational environment of the entire cryptocurrency market, which helps explain the unusual comovement in the cryptocurrency market