Approaches to inverse-probability-of-treatment–weighted estimation with concurrent treatments

Objectives: In a setting with two concurrent treatments, inverse-probability-of-treatment weights can be used to estimate the joint treatment effects or the marginal effect of one treatment while taking the other to be a confounder. We explore these two approaches in a study of intravenous iron use in hemodialysis patients treated concurrently with epoetin alfa (EPO). Study Design and Setting: We linked US Renal Data System data with electronic health records (2004–2008) from a large dialysis provider. Using a retrospective cohort design with 776,203 records from 117,050 regular hemodialysis patients, we examined a composite outcome: mortality, myocardial infarction, or stroke. Results: With EPO as a joint treatment, inverse-probability-of-treatment weights were unstable, confidence intervals for treatment effects were wide, covariate balance was unsatisfactory, and the treatment and outcome models were sensitive to omission of the baseline EPO covariate. By handling EPO exposure as a confounder instead of a joint treatment, we derived stable weights and balanced treatment groups on measured covariates. Conclusions: In settings with concurrent treatments, if only one treatment is of interest, then including the other in the treatment model as a confounder may result in more stable treatment effect estimates. Otherwise, extreme weights may necessitate additional analysis steps

Exploring Physicality in the Design Process

The design process used in the development of many products we use daily and the nature of the products themselves are becoming increasingly digital. Although our whole world is turning ever more digital, our bodies and minds are naturally conceived to interact with the physical. Very often, in the design of user-targeted information appliances, the physical and digital processes are formulated separately and usually, due to cost factors, they are only brought together for user testing at the end of the development process. This not only makes major design changes more difficult but it can also significantly affect the users’ level of acceptance of the product and their experience of use. It is therefore imperative that designers explore the relationship between the physical and the digital form early on in the development process, when one can rapidly work through different sets of ideas. The key to gaining crucial design information from products lies in the construction of meaningful prototypes. This paper specifically examines how physical materials are used during the early design stage and seeks to explore whether the inherent physical properties of these artefacts and the way that designers interpret and manipulate them have a significant impact on the design process. We present the findings of a case study based on information gathered during a design exercise. Detailed analysis of the recordings reveals far more subtle patterns of behaviour than expected. These include the ways in which groups move between abstract and concrete discussions, the way groups comply with or resist the materials they are given, and the complex interactions between the physicality of materials and the group dynamics. This understanding is contributing to ongoing research in the context of our wider agenda of explicating the fundamental role of physicality in the design of hybrid physical and digital artefacts. Keywords: Physicality; Digitality; Product Design; Design Process; Prototyping; Materials</p

Things You Can\u27t See

The following is a collection of short fiction exploring the human-dog relationship. The stories work to evade the sentimentality generally associated with fiction wherein pets or animals are featured, depicting instead the dramatic complications the canine has upon human relationship and interaction. Masters thesis: http://aquila.usm.edu/masters_theses/228

Faculty development to help preservice educators model the integration of technology in the classroom: perspectives from an action research case study

This action research case study focuses on faculty development and finding better ways to educate the faculty in modeling technology in their classroom and in their curriculum. Three School of Education faculty members and the Director of Instructional Technology Services at a small, Midwestern, liberal-arts university teamed together using participatory action research to study their practice with hopes of coming to an understanding of ways to remove some barriers to technology literacy and pedagogical issues. Three articles suitable for publication make up the body of the study. Article one is a review of literature in the field of faculty development, media centers, modeling technology, and action research. It describes what is currently happening at other schools pertaining to faculty development strategies. Article two tells the story of three faculty participants\u27 views on modeling technology in the classroom and their cyclical evolution of technology modeling throughout the duration of the study. Simple, effective tools designed to provide technology literacy instruction are described. Article three describes a study of the personal practice of the instructional technology services director at a small, Midwestern, liberal-arts university. It provides insight into his evolution in teaching philosophy as he struggled with his concept of technology literacy instruction while searching for better methods of providing faculty development in that area. The cyclical nature of the participatory action research model he utilized assisted him in improving his practice and in developing an effective educational environment for his clients; the faculty. Barriers related to faculty use of technology in the classroom are explored and ways to help remove these barriers are suggested. Discussed in all three articles is the field of change theory and the concept of people\u27s perspectives and how they deal with innovations and change

Multimodal segmentation of lifelog data

A personal lifelog of visual and audio information can be very helpful as a human memory augmentation tool. The SenseCam, a passive wearable camera, used in conjunction with an iRiver MP3 audio recorder, will capture over 20,000 images and 100 hours of audio per week. If used constantly, very soon this would build up to a substantial collection of personal data. To gain real value from this collection it is important to automatically segment the data into meaningful units or activities. This paper investigates the optimal combination of data sources to segment personal data into such activities. 5 data sources were logged and processed to segment a collection of personal data, namely: image processing on captured SenseCam images; audio processing on captured iRiver audio data; and processing of the temperature, white light level, and accelerometer sensors onboard the SenseCam device. The results indicate that a combination of the image, light and accelerometer sensor data segments our collection of personal data better than a combination of all 5 data sources. The accelerometer sensor is good for detecting when the user moves to a new location, while the image and light sensors are good for detecting changes in wearer activity within the same location, as well as detecting when the wearer socially interacts with others

A trajectory planning scheme for spacecraft in the space station environment

Simulated annealing is used to solve a minimum fuel trajectory problem in the space station environment. The environment is special because the space station will define a multivehicle environment in space. The optimization surface is a complex nonlinear function of the initial conditions of the chase and target crafts. Small permutations in the input conditions can result in abrupt changes to the optimization surface. Since no prior knowledge about the number or location of local minima on the surface is available, the optimization must be capable of functioning on a multimodal surface. It was reported in the literature that the simulated annealing algorithm is more effective on such surfaces than descent techniques using random starting points. The simulated annealing optimization was found to be capable of identifying a minimum fuel, two-burn trajectory subject to four constraints which are integrated into the optimization using a barrier method. The computations required to solve the optimization are fast enough that missions could be planned on board the space station. Potential applications for on board planning of missions are numerous. Future research topics may include optimal planning of multi-waypoint maneuvers using a knowledge base to guide the optimization, and a study aimed at developing robust annealing schedules for potential on board missions

Managing information

This chapter explores the provision of good data for monitoring the quality of primary care. Three issues need to be addressed - the kit (IT infrastructure), the way it is used, and the capability of the people using it

Subsolidus and Partial Melting Reactions in the Quartz-excess CaO+MgO+Al2O3+SiO2+H2O System under Water-excess and Water-deficient Conditions to 10 kb: Some Implications for the Origin of Peraluminous Melts from Mafic Rocks

Experimental results up to 10 kb pressure are presented on the stability of amphibole in the quartz-excess CaO+MgO+Al2O3 (CMASH) system under H2O)-excess and H2O deficient conditions. Amphibole is stable above the solidus under H2O-excess conditions whereas under H2O-deficient conditions dehydration melting of amphibole-bearing assemblages defines the solidus. The successive appearance of amphibole, talc, and zoisite with increasing pressure considerably modifies the plagioclase-pyroxene-garnet-kyanite reactions documented experimentally in the CaO+MgO+Al2O3+SiO2 system for gabbro-granulite-eclogite transitions. Although both clino pyroxene and cordierite (with anorthite+orthopyroxene+quartz) may melt eutectically at one atmosphere to form diopside-normative and corundum-normative melts respectively, at higher pressures under H2O-excess conditions the peritectic melting of mafic rock compositions produces corundum-normative liquids together with either clinopyroxene or amphibole. Dehydration melting produces melts which are not corundum-normative. These data are used to discuss the origins and evolution of contrasting basalt-andesite-dacite-rhyolite volcanic suites and granitic plutons, many of whose silicic variants are corundum-normative in character, such as the Toba luff ignimbrites, Indonesia (Beddoc-Stephens et al., 1983) and I-type granite minimum melts (White & Chappell, 1977). In contrast, it is proposed that for the Cascades basalt-andesite-dacite-rhyolite suite the ortho pyroxene-plagioclase-quartz thermal divide was maintained up to rhyolite compositions, thereby prohibiting the derivation of corundum-normative rocks from diopside-normative parent magmas. The deduced reaction relations between pyroxenes, amphibole, plagioclase, quartz, and liquid are used to explain the absence or extreme scarcity of hydrous phases in some hydrous magmas. These phase relations can also explain the development of later plagioclase overgrowths on resorbed plagioclase cores in granitic intrusives, and the general absence of resorption and overgrowths in chemically equivalent extrusive rocks. A theoretical analysis of the partial melting of forsterite-bearing assemblages in the CaO+MgO+Al2O3+SiO2+H2O system shows that under H2O-excess conditions partial melting may generate corundum-normative (but low SiO2) melts from a peridotite source at shallow depth