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Construction of a dual-tip scanning tunneling microscope: A prototype nanotechnology workstation
No full textThis dissertation describes the construction and performance of a dual-tip scanning tunneling microscope (STM). The microscope was built as a prototype nanotechnology workstation, a general purpose instrument designed to give a researcher the ability to investigate and manipulate nanometer scale structures. Chapter One describes the genesis and development of the concept of nanotechnology, from the atomic hypothesis of Democritus to modern developments in synthetic chemistry. Nanometer scale electronics (molecular electronics) is introduced and the state of the art in this field is described. The dual-tip scanning probe microscope is proposed as a way to address individual molecular electronic devices, a key goal in realizing nanometer scale electronic technology. Investigation of microtubules, a proposed nanometer scale intracellular biological information processing system, is also discussed. Chapter Two reviews the history and fundamental physics of STM, along with the related techniques of Field Ion Microscopy (FIM) and Ballistic Electon Emission Microscopy (BEEM). BEEM is used to introduce the physics of the dual-tip STM. Other dual-probe systems are also described. Chapter Three covers the design and construction of the dual-tip STM. Both hardware and software are described in detail. Chapter Four presents the results obtained with the dual-tip STM, including dual-tip images and noise measurements for the electronic circuitry. The last chapter, Chapter Five, contains suggested design changes for improving the performance of the dual-tip microscope and descriptions of experiments that can be performed with an improved instrument. Design and use of a nanotechnology workstation in the fields of semiconductor electronics, molecular electronics and cellular biology is discussed. Investigation of neurons grown on a silicon chip with a dual-tip STM system is proposed. Four Appendices present a noise model of the STM tunneling gap and preamplifier, describe calibration of the piezoelectric scanners that move the probe tips, and list the software that controls the system.This item was digitized from a paper original and/or a microfilm copy. If you need
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Integration of operating room monitors for development of a smart alarm system.
No full textA computer based system was designed and used to collect physiologic and respiratory data (13 variables and 3 waveforms) from six routinely used operating room monitors. 23 hours of data were collected during 20 general surgery cases (ASA III patients). Part of the data were used to design and implement an integrated monitor with intelligent alarm capability. The system used a rule based approach to reduce false alarms and artificial neural networks (ANN) for classification of physiological waveforms. The integrated monitor was able to correctly identify 13 of 17 intubations which resulted in a 42% reduction in low end-tidal-CO₂ false alarms. False heart rate alarms were reduced to 2.6% of total alarms using multi-variable analysis and rate of change limits. A combination of ANN's and an edge detection filter was used to classify CO₂ waveforms into spontaneous, mechanical, and mechanical with spontaneous breathing attempts. The edge detection algorithm was able to detect 171 of 182 breaths. The ANN's properly classified 65 of 67 mechanical, 47 of 71 spontaneous, and 37 of 44 mechanical breaths with spontaneous breathing attempts. Another ANN was used for detection of elevated and depressed ST segments in the ECG signal. All ST segment elevations and depressions of 0.1 mV were correctly identified. An attempt was made to use ANN's to classify ECG waveforms according to anesthetic levels. However, the back-propagation algorithm used to train the network did not converge perhaps due to the variety of drugs used in the different cases. The system met our goals of providing an integrated operating room monitor with intelligent alarm capability. The system significantly reduced false heart rate alarms, detected intubation and classified ECG and CO₂ waveforms.This item was digitized from a paper original and/or a microfilm copy. If you need
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Funda-Mentality": is the conscious mind subtly linked to a basic level of the universe?
No full textAge-old battle lines over the puzzling nature of mental experience are shaping a modern resurgence in the study of consciousness. On one side are the long-dominant "physicalists" who view consciousness as an emergent property of the brain's neural networks. On the alternative, rebellious side are those who see a necessary added ingredient: proto-conscious experience intrinsic to reality, perhaps understandable through modern physics (panpsychists, pan-experientialists, "funda-mentalists"). It is argued here that the physicalist premise alone is unable to solve completely the difficult issues of consciousness and that to do so will require supplemental panpsychist/pan-experiential philosophy expressed in modern physics. In one scheme proto-conscious experience is a basic property of physical reality accessible to a quantum process associated with brain activity. The proposed process is Roger Penrose's "objective reduction" (OR), a self-organizing "collapse" of the quantum wave function related to instability at the most basic level of space-time geometry. In the Penrose- Hameroff model of "orchestrated objective reduction" (Orch OR), OR quantum computation occurs in cytoskeletal microtubules within the brain's neurons. The basic thesis is that consciousness involves brain activities coupled to a self-organizing ripples in fundamental reality
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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