Two Applications Involving the Analytic Hierarchy Process

The analytic hierarchy process (AHP) is a popular tool used in decision making for ranking alternatives based on quantitative and qualitative criteria. In this thesis, we investigate two applications involving the AHP: determining the greatest sports records and generating priority vectors for inconsistent interval judgments. We determine rankings of the greatest active single-season, career, and single-event sports records by applying the ratings mode of the AHP. In addition, we present an extension to a linear programming method used for generating priority vectors for interval pairwise comparison matrices. By introducing multiplicative stretch factors for each interval comparison, our linear programming method with stretching can be used to solve problems when inconsistent interval judgments are present. We describe the linear programming method, apply it to three problems, and compare its performance to other methods for solving inconsistent interval AHP problems

Study of the Amplitude of Pressure and Thrust Oscillations in a Lab-Scale Hybrid Rocket

Hybrid rockets are being studied as a potential replacement for the solid rocket boosters on the NASA space shuttle. One physical characteristic of hybrid rockets that must be understood and overcome is potentially severe pressure oscillations during combustion. Pressure oscillations inside the rocket combustion chamber lead to oscillations in the thrust of the rocket. These oscillations are damaging to potential human passengers and cargo and must be minimized. Current theories surmise that the oscillations are caused by combustion chamber geometry, oxygen feed line parameters, and/or fuel combustion characteristics. This study focuses on the role of the fuel characteristics in pressure and thrust oscillations. The standard hybrid rocket fuel is hydroxyl-terminated polybutadiene (HTPB). A fuel additive, guanidinium azo-tetrazolate (GAT), has been shown to increase thrust and impulse of the rocket when added as 15% by mass to the fuel. This study compares the amplitude of the pressure and thrust oscillations of the rocket when burning HTPB fuels and when burning GAT-added fuels. Data from several firings at oxygen flow rates from 0.018 kg/sec to 0.054 kg/sec are analyzed. Results show the GAT-added fuel combustion shows no significant increase or decrease in the amplitude of the pressure and thrust oscillations

The effects of alcohol hangover on mood and performance assessed at home

The current study evaluated the next day consequences of a social night of drinking compared to a no alcohol night, with standardised mood and portable screen-based performance measures assessed in the morning at participants’ homes, and a breathalyser screen for zero alcohol. A mixed sex group (n = 20) took part in the study. Participants reported consuming on average 16.9 units (135 g) alcohol, resulting in a hangover rating of 60 (out of 100) compared to 0.3 following the no alcohol night. Statistical significance comparisons contrasting the hangover with the no alcohol condition revealed an increase in negative mood and irritability during hangover and an (unexpected) increase in risk and thrill seeking. Performance scores showed an overall slowing of responses across measures, but with less impact on errors. The results support the description of hangover as a general state of cognitive impairment, reflected in slower responses and reduced accuracy across a variety of measures of cognitive function. This suggests a general level of impairment due to hangover, as well as increased negative mood. The use of a naturalistic design enabled the impact of more typical levels of alcohol associated with real life social consumption to be assessed, revealing wide ranging neurocognitive impairment with these higher doses. This study has successfully demonstrated the sensitivity of home-based assessment of the impact of alcohol hangover on a range of subjective and objective measures. The observed impairments, which may significantly impair daily activities such as driving a car or job performance, should be further investigated and taken into account by policy makers

The IDA3 adapter, required for intraflagellar transport of I1 dynein, is regulated by ciliary length

Axonemal dyneins, including inner dynein arm I1, assemble in the cytoplasm prior to transport into cilia by intraflagellar transport (IFT). How I1 dynein interacts with IFT is not understood. We take advantage of the Chlamydomonas reinhardtii ida3 mutant, which assembles the inner arm I1 dynein complex in the cytoplasm but fails to transport I1 into the cilium, resulting in I1 dynein-deficient axonemes with abnormal motility. The IDA3 gene encodes an ∼115-kDa coiled-coil protein that primarily enters the cilium during ciliary growth but is not an axonemal protein. During growth, IDA3, along with I1 dynein, is transported by anterograde IFT to the tip of the cilium. At the tip, IDA3 uncouples from IFT and diffuses within the cilium. IFT transport of IDA3 decreases as cilia lengthen and subsides once full length is achieved. IDA3 is the first example of an essential and selective IFT adapter that is regulated by ciliary length. </jats:p

Informed choice about breast cancer prevention: randomized controlled trial of an online decision aid intervention

Abstract Introduction Tamoxifen and raloxifene are chemopreventive drugs that can reduce women's relative risk of primary breast cancer by 50%; however, most women eligible for these drugs have chosen not to take them. The reasons for low uptake may be related to women's knowledge or attitudes towards the drugs. We aimed to examine the impact of an online breast cancer chemoprevention decision aid (DA) on informed intentions and decisions of women at high risk of breast cancer. Methods We conducted a randomized clinical trial, assessing the effect of a DA about breast cancer chemoprevention on informed choices about chemoprevention. Women (n = 585), 46- to 74-years old old, completed online baseline, post-test, and three-month follow-up questionnaires. Participants were randomly assigned to either an intervention group, a standard control group that answered questions about chemoprevention at baseline, or a three-month control group that did not answer questions about chemoprevention at baseline. The main outcome measures were whether women's intentions and decisions regarding chemoprevention drugs were informed, and whether women who viewed the DA were more likely to make informed decisions than women who did not view the DA, using a dichotomous composite variable 'informed choice' (yes/no) to classify informed decisions as those reflecting sufficient knowledge and concordance between a woman's decision and relevant attitudes. Results Analyses showed that more intervention than standard control participants (52.7% versus 5.9%) made informed decisions at post-test, P <0.001. At the three-month follow-up, differences in rates of informed choice between intervention (16.9%) and both control groups (11.8% and 8.0%) were statistically non-significant, P = 0.067. Conclusions The DA increased informed decision making about breast cancer chemoprevention, although the impact on knowledge diminished over time. This study was not designed to determine how much knowledge decision makers must retain over time. Examining informed decisions increases understanding of the impact of DAs. A standard for defining and measuring sufficient knowledge for informed decisions is needed. Trial registration ClinicalTrials.gov: NCT00967824http://deepblue.lib.umich.edu/bitstream/2027.42/112557/1/13058_2013_Article_3282.pd

Baryon masses at O(a^2) in chiral perturbation theory

The chiral Lagrangian for the Symanzik action through O(a^2) for baryons is obtained. We consider two flavor unquenched and partially quenched lattice theories, allowing for mixed actions in the latter. As an application, we calculate masses to O(a^2) for the nucleons and deltas, and investigate the corrections due to the violation of O(4) rotational invariance. These results are contrasted with those in the meson sector for lattice simulations using mixed and unmixed actions of Wilson and Ginsparg-Wilson quarks.Comment: 27 pages, 2 figures, revise

Informed choice about breast cancer prevention: randomized controlled trial of an online decision aid intervention

Abstract Introduction Tamoxifen and raloxifene are chemopreventive drugs that can reduce women's relative risk of primary breast cancer by 50%; however, most women eligible for these drugs have chosen not to take them. The reasons for low uptake may be related to women's knowledge or attitudes towards the drugs. We aimed to examine the impact of an online breast cancer chemoprevention decision aid (DA) on informed intentions and decisions of women at high risk of breast cancer. Methods We conducted a randomized clinical trial, assessing the effect of a DA about breast cancer chemoprevention on informed choices about chemoprevention. Women (n = 585), 46- to 74-years old old, completed online baseline, post-test, and three-month follow-up questionnaires. Participants were randomly assigned to either an intervention group, a standard control group that answered questions about chemoprevention at baseline, or a three-month control group that did not answer questions about chemoprevention at baseline . The main outcome measures were whether women's intentions and decisions regarding chemoprevention drugs were informed, and whether women who viewed the DA were more likely to make informed decisions than women who did not view the DA, using a dichotomous composite variable 'informed choice' (yes/no) to classify informed decisions as those reflecting sufficient knowledge and concordance between a woman's decision and relevant attitudes. Results Analyses showed that more intervention than standard control participants (52.7% versus 5.9%) made informed decisions at post-test, P <0.001. At the three-month follow-up, differences in rates of informed choice between intervention (16.9%) and both control groups (11.8% and 8.0%) were statistically non-significant, P = 0.067. Conclusions The DA increased informed decision making about breast cancer chemoprevention, although the impact on knowledge diminished over time. This study was not designed to determine how much knowledge decision makers must retain over time. Examining informed decisions increases understanding of the impact of DAs. A standard for defining and measuring sufficient knowledge for informed decisions is needed. Trial registration ClinicalTrials.gov: NCT00967824http://deepblue.lib.umich.edu/bitstream/2027.42/135728/1/13058_2013_Article_3282.pd

Semidiurnal Internal Tide Energy Fluxes and Their Variability in a Global Ocean Model and Moored Observations

We examine the temporal means and variability of the semidiurnal internal tide energy fluxes in 1/25° global simulations of the Hybrid Coordinate Ocean Model (HYCOM) and in a global archive of 79 historical moorings. Low-frequency flows, a major cause of internal tide variability, have comparable kinetic energies at the mooring sites in model and observations. The computed root-mean-square (RMS) variability of the energy flux is large in both model and observations and correlates positively with the time-averaged flux magnitude. Outside of strong generation regions, the normalized RMS variability (the RMS variability divided by the mean) is nearly independent of the flux magnitudes in the model, and of order 23% or more in both the model and observations. The spatially averaged flux magnitudes in observations and the simulation agree to within a factor of about 1.4 and 2.4 for vertical mode-1 and mode-2, respectively. The difference in energy flux computed from the full-depth model output versus model output subsampled at mooring instrument depths is small. The global historical archive is supplemented with six high-vertical resolution moorings from the Internal Waves Across the Pacific (IWAP) experiment. The model fluxes agree more closely with the high-resolution IWAP fluxes than with the historical mooring fluxes. The high variability in internal tide energy fluxes implies that internal tide fluxes computed from short observational records should be regarded as realizations of a highly variable field, not as “means” that are indicative of conditions at the measurement sites over all time

Spectral decomposition of internal gravity wave sea surface height in global models

Two global ocean models ranging in horizontal resolution from 1/12° to 1/48° are used to study the space and time scales of sea surface height (SSH) signals associated with internal gravity waves (IGWs). Frequency‐horizontal wavenumber SSH spectral densities are computed over seven regions of the world ocean from two simulations of the HYbrid Coordinate Ocean Model (HYCOM) and three simulations of the Massachusetts Institute of Technology general circulation model (MITgcm). High wavenumber, high‐frequency SSH variance follows the predicted IGW linear dispersion curves. The realism of high‐frequency motions (>0.87  cpd) in the models is tested through comparison of the frequency spectral density of dynamic height variance computed from the highest‐resolution runs of each model (1/25° HYCOM and 1/48° MITgcm) with dynamic height variance frequency spectral density computed from nine in situ profiling instruments. These high‐frequency motions are of particular interest because of their contributions to the small‐scale SSH variability that will be observed on a global scale in the upcoming Surface Water and Ocean Topography (SWOT) satellite altimetry mission. The variance at supertidal frequencies can be comparable to the tidal and low‐frequency variance for high wavenumbers (length scales smaller than ∼50 km), especially in the higher‐resolution simulations. In the highest‐resolution simulations, the high‐frequency variance can be greater than the low‐frequency variance at these scales.Key PointsTwo high‐resolution ocean models compare well against data in frequency spectral density of dynamic heightSea surface height frequency‐horizontal wavenumber spectral densities show high variance along internal gravity wave dispersion curvesTwo high‐resolution ocean models give different estimates of variance in high‐frequency, high wavenumber phenomenaPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/1/jgrc22465-sup-0002-2017JC013009-fs01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/2/jgrc22465-sup-0003-2017JC013009-fs02.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/3/jgrc22465_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/4/jgrc22465.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/5/jgrc22465-sup-0007-2017JC013009-fs06.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/6/jgrc22465-sup-0009-2017JC013009-fs08.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/7/jgrc22465-sup-0004-2017JC013009-fs03.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/8/jgrc22465-sup-0005-2017JC013009-fs04.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/9/jgrc22465-sup-0006-2017JC013009-fs05.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/10/jgrc22465-sup-0001-2017JC013009-s01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139946/11/jgrc22465-sup-0008-2017JC013009-fs07.pd

Multilevel factors associated with long-term adherence to screening mammography in older women in the U.S.

In the U.S., guidelines recommend that women continue mammography screening until at least age 74, but recent evidence suggests declining screening rates in older women. We estimated adherence to screening mammography and multilevel factors associated with adherence in a longitudinal cohort of older women. Women aged 66–75 years receiving screening mammography within the Breast Cancer Surveillance Consortium were linked to Medicare claims (2005–2010). Claims data identified baseline adherence, defined as receiving subsequent mammography within approximately 2 years, and length of time adherent to guidelines. Characteristics associated with adherence were investigated using logistic and Cox proportional hazards regression models. Analyses were stratified by age to investigate variation in relationships between patient factors and adherence. Among 49,775 women, 89% were adherent at baseline. Among women 66–70 years, those with less than a high school education were more likely to be non-adherent at baseline (odds ratio [OR] 1.96; 95% confidence interval [CI] 1.65–2.33) and remain adherent for less time (hazard ratio [HR] 1.41; 95% CI 1.11–1.80) compared to women with a college degree. Women with ≥1 versus no Charlson co-morbidities were more likely to be non-adherent at baseline (OR 1.46; 95% CI 1.31–1.62) and remain adherent for less time (HR 1.44; 95% CI 1.24–1.66). Women aged 71–75 had lower adherence overall, but factors associated with non-adherence were similar. In summary, adherence to guidelines is high among Medicare-enrolled women in the U.S. receiving screening mammography. Efforts are needed to ensure that vulnerable populations attain these same high levels of adherence