Effects of age, breast density, ethnicity, and estrogen replacement therapy on screening mammographic sensitivity and cancer stage at diagnosis: review of 183,134 screening mammograms in Albuquerque, New Mexico

PURPOSE: To examine how common patient factors affect screening mammographic sensitivity and cancer stage at diagnosis. MATERIALS AND METHODS: The authors used a population-based database of 183,134 screening mammograms and a statewide tumor registry to identify 807 breast cancers detected at screening mammography. RESULTS: Sensitivity varied significantly with ethnicity, use of estrogen replacement therapy, mammographic breast density, and age. Sensitivity was 54% (13 of 24) in women younger than 40 years, 77% (121 of 157) in women aged 40-49 years, 78% (224 of 286) in women aged 50-64 years, and 81% (277 of 340) in women older than 64 years. Sensitivity was 68% (162 of 237) for dense breasts and 85% (302 of 356) for nondense breasts and 74% (180 of 244) in estrogen replacement therapy users and 81% (417 of 513) in nonusers. Sensitivity was most markedly reduced with the combination of dense breasts and estrogen replacement therapy use; there was little difference when only one factor was present. Median cancer size and the percentage of early cancers showed little change with any factors. CONCLUSION: Age is a minor determinant of mammographic sensitivity in women aged 40 years or older. Sensitivity is substantially decreased with the combination of higher breast density and estrogen replacement therapy use. There was not a notable shift in cancer outcomes in the groups with lower mammographic sensitivity. These data do not support different screening recommendations in women aged 40-49 years or in estrogen replacement therapy users.     

Thin films of CCVD Ba0.5Sr0.5TiO3 and SrTiO3 for electrically tunable coupled microstripline phase shifters

Abstract

Epitaxial barium strontium titanate and strontium titanate thin films were deposited on (100) MgO single-crystal substrates, utilizing Combustion Chemical Vapor Deposition. The as-deposited films were patterned with gold electrodes to form interdigitated structure to function as electrically tunable devices, namely, coupled microstripline phase shifters (CMPS). Microwave dielectric properties were characterized at 11–20 GHz with an applied electric field up to ±35 V/μm. A maximum figure of merit of 53°/dB at 20 GHz and 23°C was measured. The demonstrated high degree of tunability and relatively low loss showed great potential of these films for the targeted frequency agile device applications. Characterization, using SEM, EDS, and XRD, is presented in addition to microwave performance as a function of dc bias and frequency.     

Stable inversion and parameter variations

As part of the process of automatically guiding an aircraft, we have been successful in using stable inversion to compute a desired bounded state trajectory and corresponding bounded control. In addition to this feedforward control, we must also construct a regulator to address modeling errors and disturbances. With respect to modeling errors we find that the stable inversion procedures used are so accurate that the regulator can assume a simple form, say a linear regulator about the desired trajectory. We show that under the appropriate assumptions, the bounded state trajectory and bounded control computed through stable inversion depend continuously on the parameters of the system. This is a consequence of a mathematical result that we prove about the continuous dependence of the “particular solution” of a time varying nonlinear system driven by a bounded input. This is distinct from the usual continuous dependence of the initial value problem for systems.     

Sensation seeking, augmenting-reducing, and absolute auditory threshold: A strength-of-the-nervous-system perspective.

Tested 40 male and female high school and college students on the General and the Disinhibition subscales of the Sensation Seeking Scale (Form IV), the Reducer-Augmenter Scale (RAS), and the absolute auditory threshold (AAT). General sensation seeking correlated significantly with the RAS and the AAT. Both results were general across sex. These findings, that high-sensation seekers tend to be reducers and to lack sensitivity to weak stimulation, are interpreted as supporting strength-of-the-nervous-system theory more than the formulation of M. Zuckerman et al (see record 1975-02479-001). (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic Submodel Integration Using an Offer-Accept Discrete Event Simulation

Newer approaches for modelling travel behaviour require a new approach to integrated spatial economic modelling. Travel behaviour modelling is increasingly disaggregate, econometric, dynamic, and behavioural. A fully dynamic approach to urban system modelling is described, where interactions are characterized as two agents interacting through discrete events labelled as “offer” or “accept”. This leads to a natural partition of an integrated urban model into submodels based on the category of what is being exchanged, the type of agent, and the time and place of interaction.Where prices (or price-like signals such as congested travel times) exist to stimulate supply and/or to suppress demand, the dynamic change in prices can be represented either behaviourally, as individual agents adjust their expectations in response to their personal history and the history of the modelled region, or with an “auctioneer” from micro-economic theory, who adjusts average prices. When no auctioneers are used, the modelling system can use completely continuous representations of both time and space.Two examples are shown. The first is a demonstration of a continuous-time continuous-space transaction simulation with simple agents representing businesses and households. The second shows how an existing model—the Oregon TLUMIP project for statewide land-use and transport modelling—can be adapted into the paradigm.     

A multi-year composite of GVI data as a clear reflectance database

A method is developed to generate a top of the atmosphere clear reflectance from the Global Vegetation Index (GVI) product. Our goal is to use this dataset as a threshold to be applied to the forthcoming POLDER observations, for operational cloud detection. The method is based on the hypothesis that clouds add a high frequency signal to the slow variations of the surface reflectance in clear conditions. The validity of our algorithm is verified through an analysis of the temporal profile of the reflectance that it generates. We show that these profiles are better than those resulting from the simpler Maximum Value Composite (MVC) method. The method is applied to five years of GVI products and the results are used to derive a reference database which accounts for the interannual variability of the surface reflectance.     

Design and analysis of gain-scheduled control using local controller networks

This paper describes a nonlinear control structure known as a local controller network. The structure consists of a weighted combination of a number of individual controllers, each of which is valid locally in the state space of the plant. Local controller designs are based upon local models valid in operating regimes which do not necessarily contain any physical equilibria. Consequently, the transient performance can be improved. Some 'scheduling' variables determine the current operating regime, and a validity function is assigned to each local controller. A 'feedforward' component may be used in each local controller in order to compensate directly for the operating-point-dependent model offsets. The application of the local controller network approach to a nonlinear control problem, that of longitudinal vehicle dynamics control, is described. A stability analysis for the discrete-time local controller network is given in this paper and the results are compared with known theoretical guidelines for related control approaches such as gain scheduling and feedback linearization.