Teaching Diverse Orthopaedic Patient Populations About Deliberative Decision Making Skills: Testing a Design Strategy for Online Patients' Decision Aids

Hoffman, Aubri S Dartmouth College 2011 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Problem Statement. Effective patients' decision aids (PtDAs) help patients understand clinical information and reduce decisional conflict. PtDAs that also explicitly provide guidance through four "Deliberative Steps" may achieve additional gains in preparation for decision making. Methods. Two versions were created of a web-based PtDA regarding the management of chronic knee osteoarthritis. The Information-Provision version provided clinical information (with optional "More Information" links to additional detail) and implicit deliberative guidance. The Information+Deliberation version provided the same clinical information and links, as well as explicit guidance through four Deliberative Steps: 1) Information Comprehension; 2) Values Clarification; 3) Consideration of Social Resources; and 4) Formation of an Action Plan. At each step, an optional interactive "Engagement Activity" was offered. In both versions, the program tracked selection of the information links; in the Information+Deliberation version, the program tracked engagement with the optional activities. After pilot-testing, both versions were compared (N = 126) in terms of post-PtDA Preparation for Decision Making, Decision Self-efficacy, and Decisional Conflict. Sub-groups using the "More Information" links and the "Engagement Activities" were characterized. Results. There were no statistically significant across-study-group differences in mean Preparation for Decision Making, Decision Self-efficacy, or Decisional Conflict scores. Overall (N = 126), 46% of participants selected the "More Information" links. This sub-group was primarily female, Caucasian, college-degreed, reported higher decisional conflict, and had viewed the Information+Deliberation version. In the Information+Deliberation study group (n = 64), 43% used the "Engagement Activities". This sub-group was also female, Caucasian, college-educated, reported higher levels of pain and higher decisional conflict, as well as more familiarity with the decision. The percentages of engaging at each of the 4 Steps were 14%, 27%, 13%, and 22%, respectively. Conclusions. In this clinical context, explicit guidance may not improve all patients' preparation for decision making, on average. Future studies should assess whether Type II error has occurred. Different "Deliberative Styles" may exist, and may benefit more/less from explicit guidance and optional detailed clinical information and interactive engagement.

Dartmouth magnetic evolutionary stellar tracks and relations

Feiden, Gregory Alexander Dartmouth College 2013 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Strong evidence exists showing that stellar evolution models are unable to accurately predict the fundamental properties of low-mass stars. Observations of low-mass stars in detached eclipsing binaries (DEBs) indicate that stellar models under-predict real stellar radii by 5 -- 10% and predict eUective temperatures that are 3 -- 5% too hot. This dissertation provides a careful examination of this problem using the Dartmouth stellar evolution code. Accurate models of the three stars in KOI-126 are presented. These models represent the first successful stellar evolution models of fully convective stars. I then introduce a novel method for estimating the ages of young, low-mass DEBs. The method takes advantage of apsidal motion to enable the use of stellar interior structure to predict ages instead of stellar surface properties, which are prone to significant uncertainty. Next, a reanalysis of the magnitude of the mass-radius discrepancies is performed with models that account for realistic metallicity and age variation. Results suggest that discrepancies are about a factor of two smaller than previously believed, although the problem is not entirely resolved. Lastly, I describe the development of a new one-dimensional stellar evolution code that includes eUects of a globally pervasive magnetic field. This is done within the framework of the existing Dartmouth code. I find that model radius and eUective temperature discrepancies can be reconciled with a magnetic field in stars with a radiative core. The predictions from these models can be observationally tested. Fully convective stars appear insensitive to the influence of magnetic fields, in contradiction with previous studies. I suggest that deficiencies in fully convective stars may instead be related to metallicity.

New technologies for constructing C-S and C-N bonds

Savolainen, Markku Antti Dartmouth College 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Hydrothiolation of olefins represents an atom economical method to afford C--S bonds. We have developed methodology in our lab to prepare thioethers from styrenyl compounds with absolute Markovnikov selectivity using benzo[b]thiazole-2-thiol under ambient protic acid conditions. With these compounds in hand, we can then prepare stereodefined trisubstituted olefins using the modified Julia Olefination reaction. The resulting alkenes display a very high stereochemical bias towards the Z-conformation. Developing methodology to prepare these compounds remains an active area of research. While exploring the hydrothiolation chemistry we observed an unexpected result. The treatment of styrenyl compounds with 1-phenyl-1H-tetrazole-5-thiol, under elevated temperatures with catalytic Ga(OTf)3, yielded a formal Markovnikov-selective hydroamination product in lieu of the expected hydrothiolation. This is interest, as there have been few reports describing the Lewis acid-catalyzed hydroamination of olefins.

Multiplicative problems in combinatorial number theory

McNew, Nathan Dartmouth College 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

In this thesis we look at several problems that lie in the intersection between combinatorial and multiplicative number theory. A common theme of many of these problems are estimates for and properties of the smooth numbers, those integers not divisible by any large prime factors. The first is the Ramsey-theoretic problem to determine the maximal size of a subset of the integers containing no 3-term geometric progressions. This problem was first considered by Rankin, who constructed such a subset with density about 0.719. By considering progressions among the smooth numbers, we demonstrate a method to effectively compute the greatest possible upper density of a set of integers avoiding geometric progressions. Second, we consider the problem of determining which prime number occurs most frequently as the largest prime divisor on the interval [2,x ], as well as the set prime numbers which ever have this property for some value of x, a problem closely related to the analysis of factoring algorithms. This set of primes appears to be related to another subset of primes, those primes which form the vertex points of the convex hull of the prime number graph, which we consider next, obtaining improved bounds for the count of these primes up to x.. The largest prime divisor also plays a role in a more probabilistic problem we consider next, a random multiplicative walk on the residues modulo n. Finally, we consider the k-Lehmer numbers, a subset of composite integers closely related to the Carmichael numbers, and improve existing estimates for the distribution of these integers.

Generalized Fourier transforms and their applications

Wolff, Sarah Dartmouth College 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This thesis centers around a generalization of the classical discrete Fourier transform. We first present a general diagrammatic approach to the construction of efficient algorithms for computing the Fourier transform of a function on a finite group or semisimple algebra. By extending work which connects Bratteli diagrams to the construction of Fast Fourier Transform algorithms [2], we make explicit use of the path algebra connection to the construction of Gel'fand-Tsetlin bases and work in the setting of general semisimple algebras and quivers. We relate this framework to the construction of a configuration space derived from a Bratteli diagram. In this setting the complexity of an algorithm for computing a Fourier transform reduces to the calculation of the dimension of the associated configuration space. We give explicit counting results to find the dimension of these configuration spaces, and thus the complexity of the associated Fourier transform. Our methods give improved upper bounds for the general linear group, the classical Weyl groups, and homogeneous spaces of finite groups, while also recovering the best known algorithms for the symmetric group and compact Lie groups. We extend these results further to semisimple algebras, giving the first results for non-trivial upper bounds for computing Fourier transforms on the Brauer and Birman-Murakami-Wenzl (BMW) algebras. The extension of our algorithm to Fourier transforms on semisimple algebras is motivated by emerging applications of such transforms. In particular, Fourier transforms on the Iwahori-Hecke algebras have been used to analyze Metropolis-based systematic scanning strategies for generating Coxeter group elements [1]. We consider the Metropolis algorithm in the context of the Brauer and BMW monoids and provide systematic scanning strategies for generating monoid elements. As the BMW monoid consists of tangle diagrams, these scanning strategies can be rephrased as random walks on links and tangles. We translate these walks into left multiplication operators in the corresponding BMW algebra. This algebraic perspective enables the use of tools from representation theory to analyze the walks; in particular, we develop a norm arising from a trace function on the BMW algebra to analyze the time to stationarity of the walks. [1] P. Diaconis and A. Ram. Analysis of systematic-scan Metropolis algorithms using Iwahori-Hecke algebra techniques, Michigan Math. J. 48 (2000), 157-190. MR 1786485 (2001j:60132). [2] D. Maslen and D. Rockmore. Separation of variables and the computation of Fourier transforms on finite groups, I, J. Amer. Math. Soc. 10 (1997), no. 1, 169-214. MR 1396896 (97i:20019).

Novel Approaches to Targeting Innate Immunity for Cancer Immunotherapy

Lizotte, Patrick H Dartmouth College 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Many kinds of cancer, and almost universally metastatic cancer, are refractory to treatment by conventional methods: surgery, radiation, and non-specific cytotoxic chemotherapy. The dawn of the age of personalized medicine presaged 15 years ago with the completion of the human genome project has thus far largely failed to deliver on the promise of targeted therapeutics. We have recently seen the development of immunotherapy as a compliment to these methods. Immunotherapies hold an advantage in that they are not specific to driver mutations or oncogenic pathways that may change, but recognize an array of tumors antigens and can adapt over time to the emergence of new tumor cell populations with new characteristic mutations and antigens. In order to achieve systemic long-lasting anti-tumor immunity, immunosuppression in the tumor microenvironment must be overcome. We have developed technologies to accomplish this through the targeting and activation of immunosuppressive innate leukocytes that without treatment would otherwise promote tumor survival, growth, and metastasis, and inhibit the establishment of tumor-specific immunity. We have utilized an attenuated strain of Listeria monocytogenes and the self-assembling eCPMV viral-like nanoparticle. These two immunotherapies target innate leukocytes in the tumor microenvironment and induce their production of pro-inflammatory cytokines and chemokines that recruit in new effector cell subsets. Listeria and eCPMV show clear efficacy in mouse models of melanoma, ovarian carcinoma, colon cancer, and breast carcinoma. Our results highlight the value in emerging therapeutic strategies that target immunosuppressive innate immune cells in the tumor microenvironment.

Using the Eyes to Measure the Mind: Pupil Dilation Dynamics as a Biomarker of Online Attention

Kang, Olivia E Dartmouth College 2015 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Every moment of our waking lives, our brains filter large quantities of sensory data for goal relevant information. This ability to modulate our sensitivity to incoming inputs is critical in the face of an otherwise overwhelming world, and neuroscience has located a primary correlate: the locus coeruleus-norepinephrine (LC-NE) system. As informational salience changes over time, LC-NE mediates corresponding fluctuations in attention. This is true even when salience changes occur below the threshold of conscious perception. Achieving a readout of LC-NE activity, therefore, means achieving a readout of what the brain finds interesting, both within and outside the bounds of conscious awareness, and at various levels from perceptual selection to social connection. For reasons that remain poorly understood, LC-NE activity is tightly coupled with pupillary dilation. This suggests that pupil dilation patterns offer an objective, observable, and temporally sensitive readout on what the brain finds salient over time. This dissertation combines high temporal resolution pupillometry and advanced computational techniques to determine whether pupil dilation dynamics provide a biomarker of online attention. Over seven experiments we show that the pattern of pupil dilation over time can identify whether and to what individuals are attending, and that attention-based dilation patterns synchronize between people as a function of shared attention. These data further show that pupillary synchrony between people is modulated by social intelligence (e.g., cognitive empathy) and social context (i.e., group membership). Taken together, these findings suggest that high temporal resolution pupillometry provides a sensitive and objective metric for understanding when and to what people attend in dynamic, complex environments such as social interaction. Furthermore, by eliminating the need for an experimental task or self-report, high temporal resolution pupillometry can better inform how and when attention is naturally deployed, and the consequences of that deployment for shared understanding.

Constraint-based robot knot tying

Wang, Weifu Dartmouth College 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

In this thesis, we present different approaches to tying knots using robots by enforcing different types of constraints. We attack the problem from three different directions; mechanical design, motion planning with simple control strategies, and theoretical analysis. We present the first complete generalized fixture based knot tying approach that is able to arrange and tighten knots, building on Matthew Bell's work on arranging simple knots using fixtures. Physical constraints are provided by these fixtures to reduce the possible string deformation during knot tying. Fixtures are designed automatically using proposed design principles, and constructed based on the designs using 3D modelling software. First, fixtures are used to transform knots from an untangled configuration to a knotted configuration (arrangement). Furthermore, we design fixtures that can em tighten these arranged knots by pulling the open ends of the knot without sensing. These mechanical designs provide fast, reliable and repeatable knot tying devices. We also study some simple control strategies for string without the need to simulate the deformations, as part of a collaboration with Berenson. Vector fields are generated by a sequence of virtual rings, which are used to guide the motions of string as local controllers. This simple control strategy is first used in threading string through one or more small openings. The simulated experiments suggest the approach is robust to errors. The initial experiments with a Da Vinci surgical robot arm were able to thread a 3.5mm diameter yarn into a 4.9mm diameter washer under faulty sensing. We further tied knots around generic fixtures without sensing, demonstrating the capability of tying different knots around non-specific fixtures. % The future work intends to build on these preliminary results to develop autonomous knot tying strategy with minimum sensing. We at last study the tie-ability of knots. We first analyze the complexity of the knot tying task, in terms of how many points of contact are necessary and sufficient. These fingers serve as both physical and virtual constraints to stretch string into a polygonal arc, so that we can compute possible configurations of the string easily. We present provably correct algorithms to find a sufficient number of fingers for knot grasping, and simple motions that can fold knots sequentially. Further analysis of the Gauss code---a common knot description used in knot theory---and comparison between knots and weaving encourages a novel knot tying approach, using a small number of re-grasps. An algorithm is derived to compute a sufficient number of re-grasps to tie the given knot based on the Gauss code. Physical experiments are implemented to demonstrate the novel knot tying strategy, first using a Da Vinci surgical robot to tie knots autonomously, and then through collaboration between a human and an Adept Cobra industrial arm. We present robot knot tying methods to physically tie knots and understand the complexity of the task. As a special example of string manipulation, we hope to gain insights on how to better manipulate string and possibly more general flexible objects through our research.

Privacy-preserving controls for sharing mHealth data

Prasad, Aarathi Dartmouth College 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Mobile devices allow people to collect and share health and health-related information with recipients such as health providers, family and friends, employers and insurance companies, to obtain health, emotional or financial benefits. People may consider certain health information sensitive and prefer to disclose only what is necessary. In this dissertation, we present our findings about factors that affect people's sharing behavior, describe scenarios in which people may wish to collect and share their personal health-related information with others, but may be hesitant to disclose the information if necessary controls are not available to protect their privacy, and propose frameworks to provide the desired privacy controls. We introduce the concept of close encounters that allow users to share data with other people who may have been in spatio-temporal proximity. We developed two smartphone- based systems that leverage stationary sensors and beacons to determine whether users are in spatio-temporal proximity. The first system, ENACT, allows patients diagnosed with a contagious airborne disease to alert others retrospectively about their possible exposure to airborne virus. The second system, SPICE, allows users to collect sensor information, retrospectively, from others with whom they shared a close encounter. We present design and implementation of the two systems, analyse their security and privacy guarantees, and evaluate the systems on various performance metrics. Finally, we evaluate how Bluetooth beacons and Wi-Fi access points can be used in support of these systems for close encounters, and present our experiences and findings from a deployment study on Dartmouth campus.

Sounding-Rocket Studies of Langmuir-Wave Microphysics in the Auroral Ionosphere

Dombrowski, Micah P Dartmouth College 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Since their discovery in laboratory plasmas in the 1920s, Langmuir waves have been observed to be ubiquitous in plasma environments, particularly in space plasmas. From the greater solar wind to planetary foreshocks and the auroral ionosphere, Langmuir waves are a key factor mediating electron temperature, and controlling electron beam propagation and beam-plasma energy transfer. Because they are so important, Langmuir waves in the space environment have been intensively investigated; however, there remain two challenging types of experiments that are relatively lacking: three-dimensional measurements of Langmuir-wave fields, and measurements of Langmuir wave-electron correlations. This thesis works on filling these two gaps, plus development of new Langmuir-wave instrumentation. The CHARM-II wave-particle Correlator instrument was designed to study the energy transfer between electron beams and plasmas via the sorting of incoming particles by concurrent Langmuir-wave phase, allowing for direct observation of electron bunching. Data from the CHARM-II sounding rocket comprises the first such observations with statistical levels of events, revealing an association between the polarity of the resistive component of the electron phase-bunching and changes in the electron flux at the associated energy, such that a negative resistive component goes with an increase in electron flux, and vice versa, effectively showing energy flow from the beam to the waves, and subsequent enhancements of wave damping. Surprisingly, the results also show comparable amounts of resistive and reactive activity. A test-particle simulation was developed to confirm the details of the theoretical explanation for the observed effect. A three-dimensional Langmuir-wave receiver flown on the TRICE sounding rocket mission reveals the beat signature of the amplitude-modulated 'bursty' form of Langmuir waves which has been observed in many environments. An analysis of the three-dimensional data shows agreement with expected signatures of beating between pure, field-aligned, linearly polarized Langmuir waves and obliquely propagating, elliptically polarized, hybrid whistler-Langmuir waves. Finally, an autonomous digital signal processor/receiver has been refined and augmented to achieve high time- and frequency-resolution radio observations, synchronized sampling between multiple receivers, and on-board processing of data. This system was deployed on the CHARM-II rocket, resulting in measurements of the polarization of fine structures in auroral roar emissions.