Emerson's Philosophy: A Process of Becoming through Personal and Public Tragedy

Indiana University-Purdue University Indianapolis (IUPUI)This thesis explores Ralph Waldo Emerson’s philosophical becoming throughout decades of reflection and experience, particularly regarding death and slavery. Emerson was a buoyant writer and speaker, but the death of his five-year-old son and protégé, Waldo, challenged the father’s belief in Nature’s goodness and the reality of maintaining a tenaciously optimistic outlook. As he was grieving in the mid-1840s, slavery was threatening the Union, and Emerson was compelled to turn his attention to the subject of human bondage. He began his career indifferent to the plight of slaves, but as legislation about the issue brought it closer to his personal sphere, he was gradually yet firmly gripped by the tragedy of human bondage. These simultaneously existing spheres of sorrow – Waldo’s death and slavery – joined in refining Emerson’s personal philosophy toward greater utilitarian and humanitarian conduct. His letters, journals, essays, and lectures reflect the inward changes caused by outward events, and the conclusions herein are supported by modern grief studies as well as numerous philosophers, literary specialists, and historians

Development and testing of a ballistic impact loading device

Development and testing of ballistic shock loading device with projectile for producing stress waves in polymethyl methacrylate rod

Cheliped Asymmetry in the Stone Crab, Menippe mercenaria, with Notes on Claw Reversal and Regeneration

Stone crabs (Menippe mercenaria) were reared in the laboratory to determine natural handedness. Claws of feral juvenile crabs were autotomized to test for reversal and to determine stridulatory pattern sequences. All crabs less than 4 mm carapace width were right-handed (side bearing the crusher claw). Eighty-eight percent of juvenile crabs with autotomized crushers showed signs of handedness reversal after the first regenerative molt. Stridulatory sequences indicated that a normal pattern was attained after two regenerative molts. Dockside claw surveys and trap sampling programs involving several Florida stone crab populations reveal an approximate 80:20 right:left-handed ratio in adult crabs through largest sizes trapped. This indicates that adults do not reverse as readily as juveniles

Coherent virtual absorption of light in microring resonators

Light trapping and radiation process from linear reciprocal photonic resonators is one of the fundamental processes in optical science and engineering. Recently, the concept of coherent virtual absorption (CVA) of light was introduced and investigated for planar and cylindrical optical structures. The key feature of CVA is that by engineering the time-dependence of the excitation waveform, one can temporarily store all the input energy into the optical structure without any leakage. Here we further explore this novel concept in integrated photonic setups made of microring resonators. By using coupled-mode theory (CMT), we derive an analytical expression for CVA in this platform. This in turn allows us to make the connection with the notion of coherent perfect absorption (CPA) as well as extending our analysis to active resonators (having optical gain). We next provide a physical insight into this process by using a simple model made of cascaded beam splitters. Importantly, we confirm our results using a full-wave analysis of realistic material systems. Finally, we discuss the limitation on the CVA process due to waveform mismatch and nonlinear effects

Nanoelectromechanical Resonator Arrays for Ultrafast, Gas-Phase Chromatographic Chemical Analysis

Miniaturized gas chromatography (GC) systems can provide fast, quantitative analysis of chemical vapors in an ultrasmall package. We describe a chemical sensor technology based on resonant nanoelectromechanical systems (NEMS) mass detectors that provides the speed, sensitivity, specificity, and size required by the microscale GC paradigm. Such NEMS sensors have demonstrated detection of subparts per billion (ppb) concentrations of a phosphonate analyte. By combining two channels of NEMS detection with an ultrafast GC front-end, chromatographic analysis of 13 chemicals was performed within a 5 s time window

Nonuniversality of quantum noise in optical amplifiers operating at exceptional points

The concept of exceptional points-based optical amplifiers (EPOAs) has been recently proposed as a new paradigm for miniaturizing optical amplifiers while simultaneously enhancing their gain-bandwidth product. While the operation of this new family of amplifiers in the classical domain provides a clear advantage, their performance in the quantum domain has not yet been evaluated. Particularly, it is not clear how the quantum noise introduced by vacuum fluctuations will affect their operation. Here, we investigate this problem by considering three archetypal EPOA structures that rely either on unidirectional coupling, parity-time symmetry, or particle-hole symmetry for implementing the exceptional point. By using the Heisenberg-Langevin formalism, we calculate the added quantum noise in each of these devices and compare it with that of a quantum-limited amplifier scheme that does not involve any exceptional points. Our analysis reveals several interesting results: most notably that while the quantum noise of certain EPOAs can be comparable to those associated with conventional amplifier systems, in general the noise does not follow a universal scaling as a function of the exceptional point but rather varies from one implementation to another

Nonuniversality of quantum noise in optical amplifiers operating at exceptional points

The concept of exceptional points-based optical amplifiers (EPOAs) has been recently proposed as a new paradigm for miniaturizing optical amplifiers while simultaneously enhancing their gain-bandwidth product. While the operation of this new family of amplifiers in the classical domain provides a clear advantage, their performance in the quantum domain has not yet been evaluated. Particularly, it is not clear how the quantum noise introduced by vacuum fluctuations will affect their operation. Here, we investigate this problem by considering three archetypal EPOA structures that rely either on unidirectional coupling, parity-time symmetry, or particle-hole symmetry for implementing the exceptional point. By using the Heisenberg-Langevin formalism, we calculate the added quantum noise in each of these devices and compare it with that of a quantum-limited amplifier scheme that does not involve any exceptional points. Our analysis reveals several interesting results: most notably that while the quantum noise of certain EPOAs can be comparable to those associated with conventional amplifier systems, in general the noise does not follow a universal scaling as a function of the exceptional point but rather varies from one implementation to another

Nonuniversality of quantum noise in optical amplifiers operating at exceptional points

The concept of exceptional points-based optical amplifiers (EPOAs) has been recently proposed as a new paradigm for miniaturizing optical amplifiers while simultaneously enhancing their gain-bandwidth product. While the operation of this new family of amplifiers in the classical domain provides a clear advantage, their performance in the quantum domain has not yet been evaluated. Particularly, it is not clear how the quantum noise introduced by vacuum fluctuations will affect their operation. Here, we investigate this problem by considering three archetypal EPOA structures that rely either on unidirectional coupling, parity-time symmetry, or particle-hole symmetry for implementing the exceptional point. By using the Heisenberg-Langevin formalism, we calculate the added quantum noise in each of these devices and compare it with that of a quantum-limited amplifier scheme that does not involve any exceptional points. Our analysis reveals several interesting results: most notably that while the quantum noise of certain EPOAs can be comparable to those associated with conventional amplifier systems, in general the noise does not follow a universal scaling as a function of the exceptional point but rather varies from one implementation to another

Cognitive function and mood at high altitude following acclimatization and use of supplemental oxygen and adaptive servoventilation sleep treatments.

Impairments in cognitive function, mood, and sleep quality occur following ascent to high altitude. Low oxygen (hypoxia) and poor sleep quality are both linked to impaired cognitive performance, but their independent contributions at high altitude remain unknown. Adaptive servoventilation (ASV) improves sleep quality by stabilizing breathing and preventing central apneas without supplemental oxygen. We compared the efficacy of ASV and supplemental oxygen sleep treatments for improving daytime cognitive function and mood in high-altitude visitors (N = 18) during acclimatization to 3,800 m. Each night, subjects were randomly provided with ASV, supplemental oxygen (SpO2 > 95%), or no treatment. Each morning subjects completed a series of cognitive function tests and questionnaires to assess mood and multiple aspects of cognitive performance. We found that both ASV and supplemental oxygen (O2) improved daytime feelings of confusion (ASV: p < 0.01; O2: p < 0.05) and fatigue (ASV: p < 0.01; O2: p < 0.01) but did not improve other measures of cognitive performance at high altitude. However, performance improved on the trail making tests (TMT) A and B (p < 0.001), the balloon analog risk test (p < 0.0001), and the psychomotor vigilance test (p < 0.01) over the course of three days at altitude after controlling for effects of sleep treatments. Compared to sea level, subjects reported higher levels of confusion (p < 0.01) and performed worse on the TMT A (p < 0.05) and the emotion recognition test (p < 0.05) on nights when they received no treatment at high altitude. These results suggest that stabilizing breathing (ASV) or increasing oxygenation (supplemental oxygen) during sleep can reduce feelings of fatigue and confusion, but that daytime hypoxia may play a larger role in other cognitive impairments reported at high altitude. Furthermore, this study provides evidence that some aspects of cognition (executive control, risk inhibition, sustained attention) improve with acclimatization