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Correlation Between Shell Size and Presence and Size of Apertural Teeth in the Low-Intertidal Zone Snail, Nucella lamellosa
No full textThe low-intertidal zone marine gastropod, Nucella lamellosa, exhibits remarkable phenotypic plasticity between habitats as close as 100 m from one other. Shells that develop in different environments can display variation in color, banding, shape, sculpture, and thickness, and the most documented explanation for this variation is predator-induced resistance. The snails collected from the beach in front of the Friday Harbor Laboratories are of the thick-shelled variety of N. lamellosa and are known to exhibit a row of teeth within their apertural openings, presumably as a defense against their predator, Cancer productus. I collected 25 of these snails at low tide and took systematic measurements (length, width, weight) to quantify shell size, and I used high resolution images of the apertural openings to measure average tooth height and apertural lengths. I found that, while a majority of the snails (19 out of 25) displayed apertural teeth, there were 5 snails that did not (one snail exhibited drastically different morphology). Of the range of shell lengths I collected (1.03 cm – 5.84 cm), the largest snail without apertural teeth was 1.93 cm. By comparing shell width and weight to shell length, I determined that there was no significant difference between the way snails with and without apertural teeth developed; both groups showed a significant positive correlation between shell width and weight and shell length. I also found that for those snails with apertural teeth, there was a significant positive correlation between apertural length and apertural tooth height
Developing a Performance Measurement Approach to Benefit/Cost Freight Project Prioritization
No full textFuture reauthorizations of the federal transportation bill will require a comprehensive and quantitative analysis of the freight benefits of proposed freight system projects. To prioritize public investments in freight systems and to insure consideration of the contribution of freight to the overall system performance, states and regions need an improved method to analyze freight benefits associated with proposed highway and truck intermodal improvements that would lead to enhanced trade and sustainable economic growth, improved safety and environmental quality, and goods delivery in Washington State. This project develops a process to address this need by building on previous and ongoing research by some project team members with the goal of developing an agency-friendly, data-supported framework to prioritize public investments for freight systems in Washington and Oregon. The project integrates two ongoing WSDOT funded efforts: one to create methods to calculate the value of truck and truck-intermodal infrastructure projects and the other to collect truck probe data from commercial GPS devices to create a statewide Freight Performance Measures (FPM) program. This integration informs the development of a framework that allows public agencies to quantify freight investment benefits in specific areas such as major freight corridors and across borders.Pacific Northwest Transportation Consortiu
Parental disclosure of HIV status: Experiences and perceptions of HIV positive parents in Nairobi, Kenya
No full textThesis (Master's)--University of Washington, 2014Background: Research on parental disclosure of HIV status to children is limited, especially in sub-Saharan Africa where most HIV-infected adults reside. Rates of parental HIV disclosure cited in the literature range from 11-50%. We conducted a mixed methods study to examine rates of parental HIV disclosure and explore factors that influence a parent's decision to disclose their HIV status to their children in Nairobi, Kenya. Methods: Among HIV-infected parents enrolled in the ongoing Counseling and Testing for Children at Home (CATCH) study, we determined rates and cofactors of disclosure of parental HIV status to partners, family members and children. The study recruited HIV-infected adults from HIV treatment clinics and enrolled those who had at least one <12 year old child of unknown HIV status. In addition, in-depth interviews were conducted with 6 parents to ascertain perceived barriers and facilitators of the process of disclosing one's HIV status to one's child and factors that influence the decision to disclose. Results: Among 74 adult participants, median age was 35 years (IQR 32-38) with a median of 5 years since HIV diagnosis; most (84%) were female. Although 77% had disclosed their HIV status to their partner, and 55% to another family member, only 4% had disclosed their HIV status to their child (p <0.001 for both comparisons). Participants who had disclosed their HIV status to someone (partner, family member or other person) were more likely to be female, have knowledge of their partner's status, and have a longer time since HIV diagnosis. Five of the six parents interviewed in-depth planned to disclose their status to their children; all mentioned that the child's age or perceived maturity inhibited disclosure and that they feared causing their child anxiety or stress by disclosing their status. Parents mentioned that child sexual activity was a motivator for disclosure, as well as the belief that disclosing was the right thing to do and noted that peer or counseling support would be useful to gain insight on appropriate ways to disclose their status. Conclusions: The decision of parents to disclose their HIV status to their children is more complex than disclosure to other family members and is influenced by concerns regarding the child's ability to understand and process knowledge of their parents' illness and lack of insight on ways to appropriately disclose. Peer groups, counseling, and standardized guidance may be beneficial to facilitate parental disclosure
Methods for the prediction of endpoint-occurrence times in clinical trials
No full textThesis (Ph.D.)--University of Washington, 2014This research is motivated by the need to anticipate the calendar time of landmark numbers of events in a clinical trial with a time-to-event monitoring endpoint. In such trials, the observed number of events usually determines the statistical information. Thus the timing of accumulating events in the trial factors strongly into the schedule of interim analyses and Data and Safety Monitoring Board reviews, as well as the overall length of the study. Once a trial is underway, patient accrual, event, and dropout rates may deviate from those anticipated during the design of the study. Then current data from the trial itself may provide the most relevant indicators of the timing of future event occurrences. Our goal is to develop methods to predict the future calendar time of the Nth event in an ongoing clinical trial using data collected between the onset of the study and an interim data cutoff time. We describe two methods for this type of conditional event-time prediction. The first is a fully parametric method, based on maximum likelihood estimation and inference. The second is a semiparametric approach that allows for more flexible modeling of baseline hazards of patient events and loss-to-follow-up, as well as the inclusion of baseline covariate information. For each method, we discuss event-time point prediction and the construction of prediction intervals. Simulation studies are used to demonstrate the performance of the prediction methods in a variety of possible scenarios. This research was motivated by monitoring considerations in the HIV Prevention Trials Network 052 Study of the prevention of HIV-1 infection with early antiretroviral therapy, and data from the trial is used to demonstrate the proposed methods. The dissertation concludes with a discussion of possible extensions, refinements, and further applications of this research
Potential Etiologies Of Pediatric Acute Diarrhea And Assessment Of Current Treatment Guidelines In Rural Western Kenya
No full textThesis (Ph.D.)--University of Washington, 2014Introduction: Diarrhea is the second leading cause of death in children under 5 years of age and diarrhea case fatality rates are highest in sub-Saharan Africa where the HIV burden is concentrated and where laboratory infrastructure is lacking. Children who are HIV-infected or whose mother is infected with HIV but who are not infected (HIV-exposed uninfected [HEU]) may be more susceptible to specific high-risk enteric pathogens such as those associated with death and other lethal complications. Current syndromic algorithms for presumptive diarrhea diagnosis and treatment may not capture these high-risk pathogens and may require updating to reflect the most recent evidence in diarrhea causes and consequences. Methods: Nested within a surveillance study of enteric and bloodstream infections in Western Kenya, we conducted sub-studies to determine the association among HIV-infection, HIV-exposure, and pathogen prevalences (chapter 1) and to determine the diagnostic performance of the World Health Organization's Integrated Management of Childhood Illness (IMCI) syndromic guidelines at classifying suspected Shigella spp. against the gold standard of stool culture (chapter 2). Results: Risk of infection with specific pathogens differed depending on HIV infection and exposure. Over 1000 children with acute diarrhea were enrolled and at least one potential pathogen (bacterial or parasitic) was identified in 45.8% of the children. HIV-infected children were more likely to be infected with enteropathogenic Escherichia coli (EPEC) (10.7% vs. 3.6%, prevalence ratio [PR]: 2.95, P=0.008). HEU children were more likely to have Cryptosporidium species (spp.) identified than HIV-unexposed children (9.9% vs. 3.3%, PR: 2.98, P=0.003). Associations were independent of measured confounders. WHO IMCI guidelines did not perform well in correctly classifying children who may benefit from antibiotic therapy. Among the 51 children with Shigella-positive stools in whom we ascertained history of bloody stool, only 7 had a reported history of bloody stool meeting the classification for antibiotic therapy by IMCI (sensitivity: 13.7% [95% CI: 5.7%-26.6%] and PPV: 9.9% [95%CI: 4.0%-19.0%]). Among the 1,006 children without microbiologic isolation of Shigella, 942 did not have a history of bloody stools (specificity: 93.6% [95%CI: 91.8-95.0%] and NPV: 95.5% [95%CI: 94.1% - 96.7%]). Conclusion: EPEC and Cryptosporidium were more frequently detected in HIV-infected and HIV-exposed children, respectively. These data may explain recently reported increased mortality attributed to these two pathogens. Current international diarrhea guidelines do not consider suspected EPEC or Cryptosporidium infections as indication for treatment or intense follow-up. Guidelines such as the IMCI do however indicate treatment for suspected Shigella infections, but the currently used suspected Shigella criteria identified few children infected with Shigella. In the absence of laboratory diagnosis, these children may have missed the opportunity to receive potentially life-saving, and transmission-reducing, antibiotic treatment. Therefore, reductions in childhood deaths due to diarrhea in sub-Saharan Africa may require increased attention to HIV-infection in children and their caregivers as well as possible updates to current syndromic treatment and management guidelines
Constructs in Knowledge Organization Systems: Rhythm in Time, Intention, and Form
No full textIn the context of the International Society for Knowledge Organization, we often consider knowledge organization systems to comprise catalogues, thesauri, and bibliothecal classification schemes – schemes for library arrangement. In recent years we have added ontologies and folksonomies to our sphere of study. In all of these cases it seems we are concerned with improving access to information. We want a good system.And much of the literature from the late 19th into the late 20th century took that as their goal – to analyze the world of knowledge and the structures of representing it as its objects of study; again, with the ethos for creating a good system. In most cases this meant we had to be correct in our assertions about the universe of knowledge and the relationships that obtain between its constituent parts. As a result much of the literature of knowledge organization is prescriptive – instructing designers and professionals how to build or use the schemes correctly – that is to maximize redundant success in accessing information.In 2005, there was a turn in some of the knowledge organization literature. It has been called the descriptive turn. This is in relation to the otherwise prescriptive efforts of researchers in KO. And it is the descriptive turn that makes me think of context, languages, and cultures in knowledge organization–the theme of this year’s conference.Work in the descriptive turn questions the basic assumptions about what we want to do when we create, implement, maintain, and evaluate knowledge organization systems. Following on these assumptions researchers have examined a wider range of systems and question the motivations behind system design. Online websites that allow users to curate their own collections are one such addition, for example Pinterest (cf., Feinberg, 2011). However, researchers have also looked back at other lineages of organizing to compare forms and functions. For example, encyclopedias, catalogues raisonnés, archival description, and winter counts designed and used by Native Americans.In this case of online curated collections, Melanie Feinberg has started to examine the craft of curation, as she calls it. In this line of research purpose, voice, and rhetorical stance surface as design considerations. For example, in the case of the Pinterest, users are able and encouraged to create boards. The process of putting together these boards is an act of curation in contemporary terminology. It is describing this craft that comes from the descriptive turn in KO.In the second case, when researchers in the descriptive turn look back at older and varied examples of knowledge organization systems, we are looking for a full inventory of intent and inspiration for future design. Encyclopedias, catalogues raisonnés, archival description, and works of knowledge organization in other cultures provide a rich world for the descriptive turn. And researchers have availed themselves of this
Adaptive Randomization Ratios in Multi-arm Clinical Trials
No full textThesis (Master's)--University of Washington, 2014Ethics and economics are two of many motivations for streamlining the process of discovering new therapies for the treatment of human disease. Population ethics and economics dictate that any true benefit be demonstrated as quickly as possible to allow effective therapies to be marketed and distributed to patients in need, while individual ethics favor the protection of the human subjects actually enrolled in a specific research study. Adaptive designs address both of these issues by using accumulating results to modify the trial design during the trial. One statistical aspect of multi-arm clinical trial design that can be adaptively modified is the randomization ratio, such as has been proposed in the I-SPY 2 and BATTLE trials. This thesis explores the statistical properties of adaptively modifying randomization ratios to favor accrual to experimental arms whose interim results appear most promising. Biases and inflation of type I error that can arise from modifying randomization ratios, in particular in the presence of secular time trends in patient characteristics, are described and demonstrated with simulations. In addition, we show that these issues can largely be mitigated by properly accounting for randomization ratios through stratified analyses
Refining the Association Among Race, Education and Health
No full textThesis (Master's)--University of Washington, 2014Education holds a complex, multifaceted association with health. In efforts to flesh out this relationship's nuances, researchers have found that how these two factors relate is dependent upon different social characteristics. In efforts to explain the appearance of this cross-group variation, sociologist have begun to develop the theoretical framework of resource substitution. This paper seeks to add to the development of the resource substitution framework by first examining if the magnitude of health returns to additional education varies between non-Hispanic black Americans and non-Hispanic white Americans, after accounting for other measures of socioeconomic status, and then determining if said variation can adequately be described by resource substitution. Using the 2009 PSID, I find evidence to suggest that, conditioned on other socioeconomic factors, the magnitude of the health benefit from increased education does vary between blacks and whites, and that resource substitution does not hold in this scenario
The INVEST Program: An Education to Employment/Post-Secondary Education Transition Program for Students with Mid to High Functioning Autism Spectrum Disorder
No full textMaster of Social Work (MSW)The time of transition from adolescents to adulthood is a difficult one for many individuals, disability or not. One of the biggest challenges within this large developmental milestone is that of transitioning from secondary education to competitive employment or post-secondary education. Autism spectrum disorder (ASD) refers to a continuum of disorders that impact an individual's ability to function in daily life. The impacts of ASD range from mild to severe. This disorder is believed to be persistent and one that commonly causes significant social, communication, and behavioral challenges that can result in lifelong adjustment needs and supports. These autistic symptoms have often been found to affect an individual's ability to handle transitions as well as finding and maintaining competitive employment. Over the recent years, studies have shown competitive employment rates of individuals with ASD ranging between 6%-10%. Contributing factors to these low employment rates include ineffective and inappropriate transition planning for students with ASD, as well as poor collaboration between education, employment, and community agencies. Therefore, a need has been identified, by both literature and professionals, to begin a collaborative autism-focused transition model to prepare students with mid to high-functioning autism spectrum disorder for competitive employment and post-secondary education. The INVEST program provides micro, mezzo, and macro levels of intervention in order to address identified improvement areas for future transition service development including early intervention, motivation, school and adult service collaboration, multi-system transition planning collaboration, and autism awareness training. During the development of The INVEST Program Alicia Schmoker was a member of the 2014 Master's of Social Work (MSW) Advanced Standing Cohort at the University of Washington, Tacoma and social work fellow through the University of Washington Leadership Education in Neurodevelopmental and Related Disabilities Fellowship Program. Correspondence concerning this article should be addressed to Alicia Schmoker, Seattle WA. Email: [email protected]