Dartmouth Institute for Health Policy and Clinical Practice
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The Biograph Project
Get PDFThis essay details the trials and tribulations of attempting to restore 450 short films, shot between 1908 and 1913. Details discussed include a history of paper prints created for copyright purposes, and sometimes the only source of degraded material; the eclectic nature of the Biograph camera negative and the challenges of scanning it on modern scanners; the challenges of the surviving material existing in shooting order, not in final print assemblies; missing intertitles; the degradation of nitrate-based film and negative stock; subsequent reissues and re-editing of material, and missing or lost material. Finally, we discuss the challenges of dealing with temperamental and dueling archives, including infighting, internecine jealousies, and blocking of access. A series of solutions and triumphs are also documented, intended to prevent despair on the part of film scholars, buffs and historians
A Novel External Catheter for Male Obese Patients with Acquired Hidden Penises
No full textExternal urinary catheters are an important medical device frequently used for draining urine with patients who have been hospitalized, regardless of whether they are continent. External catheters are typically recommended over indwelling catheters given that they are less invasive and lower the risk of bacteriuria and symptomatic urinary tract infection. However, a major inadequacy with external catheters lies in the patient attachment mechanism, as it fails to accommodate variable peripenile anatomies. For obese male patients whose penile shaft has become partially or entirely hidden within the skin, suprapubic fat pad and edematous scrotum, an external catheter that effectively evacuates urine is not available. Furthermore, the lack of an anatomically accurate model of a patient with a hidden penis restricts the ability of caregivers to practice catheterization training, leading to further challenges in successfully caring for these patients. Our research project has addressed this gap in urological care for patients with hidden penises in two ways. First, we have developed an accurate and realistic anatomical model of a hidden penis patient. Second, we have designed a prototype external catheter anchoring device for patients with fully hidden penises. Our prototype can effectively drain urine when connected to suction, does not require adhesive and has been tested for safety, comfort and usability. Our calculations estimate this product could serve 350,000 patients annually in the US, improve the quality of care for these patients, and be an important step towards addressing the health care disparities morbidly obese patients face
A Bayesian Inversion for Emissions and Export Productivity Across the End-Cretaceous Boundary
Get PDFThe end-Cretaceous mass extinction was marked by both the Chicxulub impact and the ongoing emplacement of the Deccan Traps flood basalt province. Both of these events perturbed the environment by the emission of climate-active volatiles, primarily CO2 and SO2. To understand the mechanism of extinction, we must disentangle the timing, duration, and intensity of volcanic and meteoritic environmental forcings. In this thesis, we used a parallel Markov chain Monte Carlo approach to invert for the aforementioned volatile emissions, export productivity, and remineralization from 67 to 65 million years ago using the LOSCAR (Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir) model. The parallel inversion leverages 128 cores in a replica exchange algorithm, where each core can exchange current solutions between each other proportional to how well their model outputs match the sedimentary record. Our results closely match observed and proxy data and suggest that CO2 and SO2 emissions were decoupled, there was a two-step decline in export productivity with a protracted recovery, and there was no clear volatile impulse at the boundary. This implies that, to the extent that the Chicxulub impact made life untenable for non-avian dinosaurs, it was not directly due to its CO2 and SO2 emissions. More broadly, our methods provide a potential path forward for efficient parallel inversion of complex Earth system models, since we show that the method is perfectly scalable up to at least 512 cores. Any model for which the run-time is longer than the communication time between cores can be sped up using our method
The Political Economy of Land Development in Karachi
Get PDFAbstract
Karachi, one of the largest megacities in the world, and the economic crown jewel of Pakistan hosts upwards of 20 million people. The number is truly astounding given that the city has only developed into an urban behemoth following the departure of the British Empire. Within a span of seventy-seven years, Karachi has become home to a diverse, immigrant, working class population with immense economic promise given its status as the country’s primary port. At the same time however, the city has found itself as the center of interests for powerful political stakeholders given its proximity to the Afghan War.
It, thus, comes to no one’s surprise that the real estate in Karachi has become a site of contention for various different groups with their own vested interests in the city. At the same time, following the decolonization of the Global South and the proliferation of neoliberal economic ideas in the world, the ideas of “urban development” modeled after international capital hubs as markers of economic success have also taken root in postcolonial states. In megacities like Karachi where the political environment remains volatile, elite capture has become normalized via state institutions that continue their jurisdictional overreaches, and there is a huge working class populace trying to make ends meet, this naturally creates a housing crisis.
In this paper, I attempt to examine Karachi’s urban development landscape as it has evolved over the years through the episteme of postcolonial Marxist urbanism, identify the core problems that plague the city’s urban landscape in particular the housing market, and analyze the complex web of political stakeholders in the city that have rendered Karachi among the least livable cities in the world, even as it rapidly develops
Leveraging Uncertainty to Understand the Causes and Consequences of Observed Climate Change
Get PDFDetecting and attributing climate change to date is essential to understanding the harm global warming has caused and the threat it poses in the future. Yet detecting and attributing historical climate change and its attendant impacts is challenging owing to observational uncertainties in the historical record, the difficulty of isolating the forced response from unforced variability, and the methodological ambiguity on how to best map climate variability and change onto climate impacts. In this thesis, I use the study system of Northern Hemisphere snow to demonstrate how synthesizing a wide array of observational and climate model data with methods from statistics, machine learning, and detection and attribution can not only manage these sources of uncertainty, but leverage them into scientific insights and useful operational information. In my first chapter, I provide strong evidence for a previously-elusive anthropogenic fingerprint of climate change on long-term snowpack trends at both the hemispheric and river basin scales. I also identify a crucial nonlinear temperature sensitivity of snowpack that explains both why snow loss has only emerged in particular midlatitude regions and why it will accelerate with further warming. In my second chapter, I build this work, illustrating how the statistical properties of wintertime temperatures explain this nonlinearity, and suggest a future with a dramatically increasing risk of low-snow extremes, or snow droughts, in these temperature-sensitive regions. In my third chapter, I demonstrate how considering all attendant uncertainties around how these snow droughts are measured and defined can improve the ability to forecast their impacts. Finally, in my last chapter, I extend this work into a new domain, highlighting how many of these lessons drawn from studying snowpack can be applied to the study of record-breaking daily temperatures, helping us develop approaches to evaluate climate models in the presence of uncertainty. Combined, my dissertation not only provides new insights about fundamental science questions, but offers a highly generalizable set of practices that can be applied to the study of climate change and its impacts more widely
ROBUST AND GENERALIZABLE REPRESENTATIONS IN THE HIPPOCAMPUS
Get PDFAn intelligent system must balance generalizing across similar experiences with maintaining the distinctiveness of each experience. This thesis explores how the hippocampus manages this balance through its neural representations to support adaptive behavior. In Chapter 1, I provide an overview of key hippocampal phenomena that contribute to this process, including remapping, splitter signal, and replay. In Chapter 2, I challenge the concept of random remapping by showing that it is possible to predict, better than chance, how a given experience will be encoded in the hippocampus across different subjects. This suggests that encoding of related experiences, which was previously thought to be random, actually follows a structured and generalizable pattern shared across individuals. In Chapter 3, I investigate how the hippocampus updates its activity patterns to generalize behaviors learned in one experience to another. Specifically, when a new aversive memory becomes linked to a previously neutral one, I show that the representation of the neutral context changes to become more similar to that of the aversive context. Importantly, this shift is modulated by the animal\u27s behavioral state. In Chapter 4, I present a normative explanation for paradoxical replay, a phenomenon where rats replay less-experienced trajectories during tasks with unbalanced experience. I demonstrate that paradoxical replay serves an adaptive function, protecting certain task representations under these conditions. Additionally, I show a striking correlation between greater splitter strength and a larger bias toward paradoxical replay, highlighting a novel interaction between the nature of task representations and the function role of replay. Lastly, in Chapter 5, I discuss open questions and propose future research directions to further investigate how the hippocampus supports the balance between generalization and differentiation through its neural representations