A low-noise microluminometer for a bioluminescent bioreporter integrated circuit

This thesis presents the analysis and design of a low-noise microluminometer for a hybrid electronic/biological chemical sensor known as a Bioluminescent Bioreporter Integrated Circuit (BBIC). The microluminometer consists of photodetection and signal processing Both functions are integrated in a standard bulk CMOS process (HP 0.5 urn CMOS). The photodetection is first described in terms of physical operation. The implementation of photodetectors in a CMOS integrated circuit process is then presented. The signal processing system is analyzed, and the errors introduced by individual system components are described. A detailed system-level noise analysis is also presented The design of a low-noise amplifier is the focus of this thesis. The amplifier design is described in detail. Finally, the results from testing of the fabricated prototype are presented

Elegies for Empire: The Poetics of Memory in the Late Work of Du Fu (712-770)

This dissertation explores highly influential constructions of the past at a key turning point in Chinese history by mapping out what I term a poetics of memory in the more than four hundred poems written by Du Fu (712-770) during his two-year stay in the remote town of Kuizhou (modern Fengjie). A survivor of the catastrophic An Lushan rebellion (756-763), which transformed Tang Dynasty (618-906) politics and culture, Du Fu was among the first to write in the twilight of the Chinese medieval period. His most prescient anticipation of mid-Tang concerns was his restless preoccupation with memory and its mediations, which drove his prolific output in Kuizhou. For Du Fu, memory held the promise of salvaging and creatively reimagining personal, social, and cultural identities under conditions of displacement and sweeping social change. The poetics of his late work is characterized by an acute attentiveness to the material supports--monuments, rituals, images, and texts--that enabled and structured connections to the past. The organization of the study attempts to capture the range of Du Fu's engagement with memory's frameworks and media. It begins by examining commemorative poems that read Kuizhou's historical memory in local landmarks, decoding and rhetorically emulating great deeds of classical exemplars. The second chapter explores the shifting boundaries Du Fu draws between the customs of Kuizhou's local people and the orthodox ritual practices that defined his identity as a scholar-official. This is followed by an interlude that discusses poems on housework, in which domesticating projects spur reflection on poetry's capacity to create cultural value through commemoration. Chapter three turns to poems on paintings, arguing that for Du Fu painted images served as a vital support for memory of pre-rebellion court society, and that in writing on them he both drew upon and redefined a medieval visual aesthetic of craft and pictorial illusionism. The fourth and final chapter analyzes the rhetoric of narrative autobiographical poems, traditionally approached as non-figurative factual records, in order to elucidate Du Fu's retrospective construction of a self. A picture thus emerges of a body of work in which memory, mediated through material objects and practices, functioned to envision and rebuild frameworks of identity in an age of upheaval and transition. This study will contribute to a more critical understanding of a major poet, of the representation and uses of memory in traditional Chinese poetry, and of the emergence of new forms of expression and literati identity in late medieval China

A new measurement of the cosmic ray energy spectrum between 3 x 10 to the 15th power eV and 3 x 10 to the 16th power eV

A new Cerenkov photon density spectrum measurement is reported. The derivation of the primary cosmic ray energy spectrum for energies from 3x10 to the 15th power eV to 3x10 to the 16th power eV are presented

Evaluating candidate reactions to selection practices using organisational justice theory

Objectives: This study aimed to examine candidate reactions to selection practices in postgraduate medical training using organisational justice theory. Methods: We carried out three independent cross-sectional studies using samples from three consecutive annual recruitment rounds. Data were gathered from candidates applying for entry into UK general practice (GP) training during 2007, 2008 and 2009. Participants completed an evaluation questionnaire immediately after the short-listing stage and after the selection centre (interview) stage. Participants were doctors applying for GP training in the UK. Main outcome measures were participants’ evaluations of the selection methods and perceptions of the overall fairness of each selection stage (short-listing and selection centre). Results: A total of 23 855 evaluation questionnaires were completed (6893 in 2007, 10 497 in 2008 and 6465 in 2009). Absolute levels of perceptions of fairness of all the selection methods at both the short-listing and selection centre stages were consistently high over the 3 years. Similarly, all selection methods were considered to be job-related by candidates. However, in general, candidates considered the selection centre stage to be significantly fairer than the short-listing stage. Of all the selection methods, the simulated patient consultation completed at the selection centre stage was rated as the most job-relevant. Conclusions: This is the first study to use a model of organisational justice theory to evaluate candidate reactions during selection into postgraduate specialty training. The high-fidelity selection methods are consistently viewed as more job-relevant and fairer by candidates. This has important implications for the design of recruitment systems for all specialties and, potentially, for medical school admissions. Using this approach, recruiters can systematically compare perceptions of the fairness and job relevance of various selection methods

Evaluation of the American Dream Demonstration: Final Evaluation Report

Evaluation of the American Dream Demonstration: Final Evaluation Repor

Quantum intensity noise correlation in a Type-II phase matched optical parametric oscillator

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 104-105).by Steven Gregory Patterson.M.S

Bipolar cascade lasers

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references.This thesis addresses issues of the design and modeling of the Bipolar Cascade Laser (BCL), a new type of quantum well laser. BCLs consist of multiple single stage lasers electrically coupled via tunnel junctions. The BCL ideally operates by having each injected electron participate in a recombination event in the topmost active region, then tunnel from the valence band of the first active region into the conduction band of the next active region, participate in another recombination event, and so on through each stage of the cascade. As each electron may produce more than one photon the quantum efficiency of the device can, in theory, exceed 100%. This work resulted in the first room temperature, continuous-wave operation of a BCL, with a record 99.3% differential slope efficiency. The device was fully characterized and modeled to include light output and voltage versus current bias, modulation response and thermal properties. A new singlemode bipolar cascade laser, the bipolar cascade antiresonant reflecting optical waveguide laser, was proposed and modeled.by Steven G. Patterson.Ph.D

Use of Redox Probes for Characterization of Layer-by-Layer Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes

The electrochemical characteristics of bare and surface-modified screen-printed carbon electrodes (SPCEs) were compared using voltammetric responses of common redox probes to determine the potential role of nanomaterials in previously documented signal enhancement. SPCEs modified with gold nanoparticles (AuNPs) by layer-by-layer (LbL) electrostatic adsorption were previously reported to exhibit an increase in voltammetric signal for Fe(CN)63−/4− that corresponds to an improvement of 102% in electroactive surface area over bare SPCEs. AuNP-modified SPCEs prepared by the same LbL strategy using the polycation poly(diallyldimethylammonium chloride) (PDDA) here were found to provide no beneficial increase in electroactive surface area over bare SPCEs. Though similar improvement in voltammetric signal of Fe(CN)63−/4− was found for AuNP/PDDA-modified compared to bare SPCEs in these studies, results with other redox couples ferrocene methanol (FcMeOH/FcMeOH+) and Ru(NH3)63+/2+ indicated no difference between the electroactive surface areas of modified and bare SPCEs. Furthermore, gold present on AuNP/PDDA-modified SPCEs accounted for only 62 (±12)% of the electroactive surface area. The previously reported improvement in electroactive surface area that was attributed to the inclusion of AuNPs on the SPCE surface appears to have resulted from a misinterpretation of the non-ideal behavior of Fe(CN)63− as a redox probe for bare SPCEs

An Experimental Approach to a Rapid Propulsion and Aeronautics Concepts Testbed

Modern aircraft design tools have limitations for predicting complex propulsion-airframe interactions. The demand for new tools and methods addressing these limitations is high based on the many recent Distributed Electric Propulsion (DEP) Vertical Take-Off and Landing (VTOL) concepts being developed for Urban Air Mobility (UAM) markets. We propose that low cost electronics and additive manufacturing can support the conceptual design of advanced autonomy-enabled concepts, by facilitating rapid prototyping for experimentally driven design cycles. This approach has the potential to reduce complex aircraft concept development costs, minimize unique risks associated with the conceptual design, and shorten development schedule by enabling the determination of many "unknown unknowns" earlier in the design process and providing verification of the results from aircraft design tools. A modular testbed was designed and built to evaluate this rapid design-build-test approach and to support aeronautics and autonomy research targeting UAM applications utilizing a complex, transitioning-VTOL aircraft configuration. The testbed is a modular wind tunnel and flight model. The testbed airframe is approximately 80% printed, with labor required for assembly. This paper describes the design process, fabrication process, ground testing, and initial wind tunnel structural and thermal loading of a proof-of-concept aircraft, the Langley Aerodrome 8 (LA-8)

The Dynamic Integration of Content and Language during Bilingual Discussion of Mathematics Word Problems

This study explores the discourse strategies adopted by a bilingual tutor to integrate content and second language learning, and support a student with limited English proficiency while discussing a set of word problems. Our findings reveal an integrated curriculum space wherein instructional focus oscillates between language and content. Pedagogical scaffolding was accomplished through strategic interspersing of pedagogical supports characterised by a linguistic focus (attention to words exchanged) or an epistemic focus (attention on mathematical ideas). Central to linguistically focused strategies was the deployment of oral translation techniques (literal translation, borrowing, modulation, and equivalence). By contrast, epistemically focused strategies entailed metaphorical gesticulation of abstract concepts in a more concrete spatialised form. It is argued that learning content in a second language requires more than vocabulary instruction at the beginning of content lessons. A more flexible approach is needed wherein English learners are provided with just-in-time support as new language naturally emerges