Investigation and modeling of uranium polarization for the electrorefining of Scrap U-MO foils

A uranium molybdenum alloy fuel has been proposed to convert research and test reactors from highly enriched uranium to low enriched uranium to increase the proliferation resistance at such reactors. Pyroprocessing has been selected to recover uranium from the scrap produced in the manufacture of this novel fuel type. Electrorefining, the main separation process of pyroprocessing, is modeled through a novel approach using corrosion theory. To use corrosion theory, knowledge of uranium polarization and kinetic parameters such as Tafel constant, transfer coefficient and exchange current density are required. Uranium polarization was investigated at five temperatures and three scan rates in both the anodic and cathodic directions. Anodic polarization of uranium revealed complex behavior caused by a buildup of a film-like material. This material was identified as a precipitate, K2UCl5, which forms as U3+ ion concentration exceeds a solubility limit in the diffusion layer adjacent to the electrode surface. The presence of the film material on the anode caused the polarization to experience reduced current density and a passive region of overpotential where current density was independent of overpotential. At large overpotentials, \u3e250mV, active dissolution behavior was observed. The temperature dependence of the polarization behavior was examined and supports the conclusion that precipitation of K2UCl 5 is the cause for the behavior. ^ Kinetic parameters were obtained from polarization data taken carefully in the pre-Tafel region to avoid film formation interference. The Oldham-Mansfeld method was used to analyze the data and obtain polarization resistance, Tafel constant, transfer coefficient and exchange current density values of high precision. The data were compared to the values available in the literature. Tafel constant values agreed reasonably well, while exchange current density did not. Errors in the methodology used in the literature to produce the exchange current density values were identified as the potential cause of the disagreement. ^ The complex uranium polarization behavior observed in the experimental work was modeled empirically and the empirical polarization model implemented in an electrorefiner model constructed in MatLab using corrosion theory. The model was compared to data obtained by experiment at laboratory-scale. The comparison demonstrated that the empirical polarization model developed is a good first approximation of the electrochemical behavior of the system, but a physically meaningful model should be developed in the future to better elucidate the chemistry in the system

Essays on the Economic Impact of Conflict on Communities and Individuals

This dissertation uses varying approaches to examine effects of war on communities and individuals in developing countries, specifically in Liberia, West Africa. The first essay, based on work published jointly with Robert E. Moore in 2012, uses a case study of Saclepea, Liberia, to illustrate the role that an appropriately designed local economic development (LED) plan can play in a rural African community emerging from crisis. This case demonstrates the need for the involvement and cooperation of many parties. Clear understanding of the stage of assistance helps to define the role of each entity. This case confirms that local participation in development efforts is an important factor in the success of these efforts. The second essay compares post-war earnings and educational attainment of former child soldiers, adult soldiers, and non-soldiers in post-war Liberia. The results indicate that the war in Liberia had different effects on soldiers than on non-soldiers, but effects for soldiers do not differ greatly between those who fought as children and those who fought as adults. Lasting effects for former soldiers do not, in sum, seem to be negative. Third, I take an experimental approach to understanding trust and trustworthiness among former child soldiers in Liberia. Liberian subjects’ decisions in the standard investment game indicate that former child soldiers do not differ in trusting behavior from other subjects. Non-soldiers are less trusting than adult soldiers, and child soldiers are less trustworthy than adult soldiers. Among only child soldiers, those who had only witnessed violence are more trustworthy than those who had been victims of violence. Liberians in this experiment tend to trust more than Americans who played the same investment game previously. The final essay examines many instances of the same investment game to explore how violence affects trusting and trustworthy behaviors and how those behaviors affect a country’s level of peacefulness. I find that a macroeconomic peace index can predict trust but not trustworthiness. Trustworthiness does affect peacefulness

Brooding, Avoidance, and Suppression as Mechanisms Linking Shame-Proneness with Depressive Symptoms

Depression is a significant mental health concern. Cognitive-affective models of depression identify that negative emotions and cognitive strategies for responding to negative emotions contribute to the development and maintenance of depressive symptoms. Shame has been identified as a problematic negative emotion and is associated with multiple mental health concerns including depression. Research has begun to examine cognitive emotion regulation strategies individuals use when experiencing shame and how these contribute to depressive symptoms. This study examined three strategies jointly (avoidance, brooding, and suppression) in a three-part prospective design. In a sample of 137 young adults, three hypotheses were tested. Participants ranged from 18 to 29-years-old (M = 19.29, SD = 1.56), 83.2% of the participants were female, and 74.5% were Caucasian. In cross-sectional analyses, shame-proneness predicted depressive symptoms (B = .029, 95% CI = .010 to .048, p = .003) and brooding mediated this relationship as hypothesized (B = .010, 95% CI = .003 to .019, p = .005). In prospective analyses shame-proneness marginally predicted depressive symptoms (B = .016, 95% CI = -.002 to .033, p = .074) and only suppression mediated the relationship when controlling for guilt-proneness (B = .012, 95% CI = .004 to .024, p = .002). Post hoc analyses of each mediator examined separately supported avoidance (B = .018, Z = 3.251, p = .001), brooding (B = .020, Z = 3.501, p = .001), and suppression (B = .022, Z = 3.602, p \u3c .001) as cognitive strategies in the relationship between shame-proneness and depressive symptoms prospectively. State shame was predicted to mediate the relationship between shame-proneness and state brooding, avoidance, and suppression. The shame induction did induce a significant change in shame [t (114) = -2.814, p = .006] but a small effect (r = .25). Therefore, hypothesis 3 was not supported. However, shame-proneness did predict use of avoidance (B = .003, p = .048) and brooding in the moment (B = .003, p = .071). These findings suggest that shame-proneness and avoidance, brooding, and suppression are significant factors to consider in treating depression. Future directions of research and clinical implications are discussed

Redefining Virtue in Shakespeare\u27s Merry Wives of Windsor

Shakespeare’s The Merry Wives of Windsor is a play of social justice. It is a staging of the type of power that women can harness in spaces of extreme limitation and violation. The female characters in this play, specifically Mistress Page and Mistress Ford, are able to use tools of oppression meant to keep them subordinate to men to achieve their personal objectives

Trends in medically-indicated versus spontaneous preterm birth, 2004-2013

BACKGROUND: Despite decades of research aimed at prevention, preterm birth remains an enormous leading cause of infant mortality in the United States and worldwide. Of concern, racial disparities in preterm birth remain an intractable public health issue. In an effort to reduce preterm birth, organizations such as the American Congress of Obstetricians and Gynecologists (ACOG) released policy statements in 2009 aimed at reducing early elective deliveries. Subsequently, the incidence of preterm birth in the United States has decreased, but whether this decrease is due to a reduction in iatrogenic or "medically-indicated" preterm birth is unknown. Further, the effect of the reduction in early elective deliveries on racial disparities is unknown. Our hypotheses were that 1) after 2009, preterm births would be less likely to be medically-indicated than due to spontaneous causes and 2) black-white differences in preterm births would be unchanged. OBJECTIVES: 1) Determine the proportion of preterm deliveries at Beth Israel Deaconess Medical Center (BIDMC) from 2004-2013 that were medically-indicated versus spontaneous. 2) Due to persistent disparities, determine if shifts in type of preterm delivery varied by race/ethnicity. METHODS: We reviewed the first 87 deliveries in 2013 and randomly selected 15% of the records for each year from 2004-2013. Additionally, we reviewed 69 charts to oversample black women's deliveries. We manually abstracted data from BIDMC's online medical record and designated each delivery as either medically-indicated (preeclampsia, poor fetal growth, hypertension, or other fetal/maternal condition) or spontaneous (preterm labor, preterm premature rupture of membranes or cervical incompetence). Two reviewers independently reviewed 18 records for concordance of medically-indicated versus spontaneous preterm birth typing. If the first reviewer could not phenotype the delivery, then a neonatologist and obstetrician were consulted. We reviewed 971 out of the 5,566 preterm deliveries and included 930 that were confirmed preterm and had a clear medically-indicated or spontaneous phenotype. We dichotomized the time period into early (2004-2009) and late (2010-2013). Statistical methods included comparisons of early versus late using Chi-Square tests, logistic regression models to adjust for potential confounding variables, and stratified analyses (singletons and black versus white). RESULTS: There were 46,981 deliveries at our institution during the study period, 5,566 of which were preterm. Among the 930 preterm deliveries sampled from the 10-year period, 45.6% were medically-indicated with a non-significant, subtle difference between the early (48.3%) and late (41.9%) (P=0.05) time periods. The odds ratios of medically-indicated versus spontaneous preterm birth in late versus early were 0.77 (P=0.05) and 0.73 (P=0.03) for all participants, unadjusted and adjusted, respectively. While not statistically significant, a higher proportion of preterm deliveries among black women were medically-indicated in the early (50.4%) versus late (40.6%) periods (P=0.19). There was a similar trend among white women between the early (50.0%) and late (46.9%) periods (P=0.48). The odds ratios of medically-indicated versus spontaneous preterm birth from late versus early were 0.67 (P=0.19) and 0.63 (P=0.14) for black participants, unadjusted and adjusted, respectively. For white participants, the odds ratios were 0.88 (P=0.48) for unadjusted and 0.80 for adjusted (P=0.20). Overall at BIDMC, the preterm delivery rate was significantly higher in the early period (12.3%) compared to the later period (11.2%) (P=0.0003). While we observed a reduction of preterm birth among all women, black women experienced a 20.8% decrease (from 16.2% in the early period to 12.8% in the late) in preterm birth, while white women experienced just a 4.9% decrease (from 12.4% to 11.7%), resulting in a narrowing of the racial disparity of preterm birth in our institution. CONCLUSION: At a Massachusetts birth hospital we found a reduction in the incidence of preterm deliveries over a 10-year period that coincided with policy efforts to reduce early elective deliveries. There was a reduction in the proportion of preterm births that were medically-indicated from 48.3% to 41.9%. The reduction in medically-indicated preterm birth was most evident among black women at BIDMC with concurrent decrease in the overall preterm birth rate among black women resulting in a near elimination of the racial disparity in preterm birth at BIDMC. Future work includes statistical analysis to account for the oversampling of deliveries in 2013 as well as oversampling of black women's deliveries using inverse probability weighting. We also plan to analyze which underlying conditions (preeclampsia, intrauterine growth restriction, fetal distress, etc.) were responsible for the reduction of the medically-indicated deliveries

Surviving Oncology: Living With Cancer in the Wake of Integrative Care

This dissertation analyzes the emerging medical field of integrative oncology, attending to how this approach to cancer treatment unsettles and reconfigures existing biomedical ideas about bodies and cancer. Informed by twelve months of multi-sited ethnographic study conducted in the state of California, it examines the attempts made by integrative practitioners to provide whole patient care by incorporating complementary medicines such as Ayurveda and Chinese medicine into conventional oncology. I suggest that this approach enacts a kind of sensitivity for how cancer is lived as a disease conditioned by emotional, psychological, social, and environmental factors, requiring treatments attentive to these dimensions. Throughout this study I grapple with the intentions of integrative oncologists and the realities of the political economy of medicine and insurance in the United States that leaves integrative care out of the reach of most people, producing a situation where many are strained to imagine different ways of surviving oncology. At the core of this project is a concern for what it means and what it takes to live well with cancer in biomedicine

The transmitted HIV-1 subtype C: characterization of the transmitted/founder full-length virus genome and the influence of early immune selective pressure on virus replication

Includes bibliographical references.The identification of targets of early immune responses associated with control of HIV-1 infection will inform immunogen design for vaccine interventions. The early evolution of transmitted/founder subtype C virus sequences was investigated to determine the location and frequency of immune selection, and the impact of early immune escape mutations on viral replicative capacity. Single-genome amplified env sequences from 26 acutely-infected women were evaluated for conformance to a model of random evolution to elucidate multiplicity of infection. Near fulllength genome sequences from the first six months of infection were generated for five women and sites evolving under immune selection were mapped. CD8+ cytotoxic Tlymphocyte escape mutations in HLA-B-restricted epitopes were introduced into infectious molecular clones of cognate transmitted/founder viruses by site-directed mutagenesis and their impact on viral replicative fitness was evaluated using parallel replication assays. In 77% of women (n=20) a single transmitted/founder variant established infection and two to five variants in the remaining 23% (n=6). Near full-length genome sequencing in five women confirmed single variant/low-diversity transmission and identified fifty-five genome regions evolving under immune selection, 40% of which was attributed to CD8+ cytotoxic Tlymphocyte pressure, 35% to antibody-mediated pressure, 16% to reversion and 9% could not be classified. The rate of sequence diversification and number of sites evolving under immune selection was highest in nef. The majority of evolving CD8+ cytotoxic T-lymphocyte epitopes (82%) contained shuffling/toggling mutations. A novel B*15:10-associated mutation, A164T, combined with a V85A Pol mutation reduced viral replication capacity in one individual. In a second individual, the attenuating HLA-B*58:01-associated mutation, T242N, enhanced viral replication capacity due to pre-existing compensatory polymorphisms in the transmitted/founder virus. A third individual, who had extremely rapid disease progression, was infected with the virus with the highest replication capacity. This thesis describes the complex nature of early immune selection and escape in transmitted/founder viruses. Although attenuating escape mutations were identified in viruses from two individuals, this was not associated with clinical benefit. The extensive variability of epitopes evolving under early selection may implicate many early immune targets as poor candidates for vaccine immunogens; however some early targets may be useful if clinical benefit is conferred through attenuating escape mutations

Still Desperately Seeking Citations: Undergraduate Research in the Age of Web-Scale Discovery.

Web-scale discovery services promise fast, easy searching from a single Google-like box, pleasing users and making library resources more discoverable. Some librarians embrace the concept of giving users what they have come to expect from Google, while others are concerned that this will “dumb down” searching and undermine information literacy. In this paper we explore the potential impact of web-scale discovery tools on information literacy, focusing particularly on undergraduate research skills. We review the existing literature and present findings and experiences from two mid-sized academic libraries that have adopted EBSCO Discovery Service as their library home page portal

Active spectral imaging

With the ability to image a scene in tens to hundreds of spectral bands, multispectral and hyperspectral imaging sensors have become powerful tools for remote sensing. However, spectral imaging systems that operate at visible through nearinfrared wavelengths typically rely on solar illumination. This reliance gives rise to a number of limitations, particularly with regard to military applications. Actively illuminating the scene of interest offers a way to address these limitations while providing additional advantages. We have been exploring the benefits of using active illumination with spectral imaging systems for a variety of applications. Our laboratory setup includes multispectral and hyperspectral sensors that are used in conjunction with several laser illumination sources, including a broadband white-light laser. We have applied active spectral imaging to the detection of various types of military targets, such as inert land mines and camouflage paints and fabrics, using a combination of spectral reflectance, fluorescence, and polarization measurements. The sensor systems have been operated under a variety of conditions, both in the laboratory and outdoors, during the day and at night. Laboratory and outdoor tests have shown that using an active illumination source can improve target-detection performance while reducing false-alarm rates for both multispectral and hyperspectral imagers

The Evolving Role of Semiconductor Consortia in the United States and Japan

This article examines the interactions between public and private actors as cooperation in the semiconductor industry becomes increasingly international. The latest manifestations of multilateral collaboration are two consortia: I300I based in the United States and Selete based in Japan. Through an analysis of their structures and their origins, this article provides a deeper understanding of the complexities facing industry-wide consortia, the role of the government in promoting or inhibiting cooperation, and the lingering rivalries that impede truly global cooperation in a dynamic, high-technology industry