Physical Sciences and Mathematics Commons^™

Successful Aging And Creativity : An Investigation On Functional Status And Psychological Wellbeing In Older Adults, Mirie E. Levy

Loma Linda University Electronic Theses, Dissertations & Projects

Objectives: While the literature supports the maintenance of functional status as integral to successful aging, the relationship of creativity on functional status has received little attention. Creativity has been associated with health and aging in the research but only a small number of studies have examined creativity interventions to enhance functional status and boost psychological wellbeing.

Methods: A pretest-posttest quasi-experimental design was used to investigate an 8-week creativity intervention on functional status and psychological wellbeing in older adults. Sample subjects were 92 men and women all over age 60. A series of two-way mixed ANOVAs measured differences between treatment and …

Statistical Inference For Data Adaptive Target Parameters, Mark J. Van Der Laan, Alan E. Hubbard, Sara Kherad Pajouh

U.C. Berkeley Division of Biostatistics Working Paper Series

Consider one observes n i.i.d. copies of a random variable with a probability distribution that is known to be an element of a particular statistical model. In order to define our statistical target we partition the sample in V equal size sub-samples, and use this partitioning to define V splits in estimation-sample (one of the V subsamples) and corresponding complementary parameter-generating sample that is used to generate a target parameter. For each of the V parameter-generating samples, we apply an algorithm that maps the sample in a target parameter mapping which represent the statistical target parameter generated by that parameter-generating …

Process Characterization Using Response Surface Methodology, Katherine A. Eng

Statistics

A local engineering firm proposed a joint collaboration with the Cal Poly Statistics Department to investigate the sources of variability in a certain measurement process, understand normal operability characteristics of the machine, reduce variability in machine measurements, establish process monitoring and control for the system, and verify utility of the proposed process control through designed experimentation. This senior project entailed designed experimentation and analysis using response surface methodology to better understand the normal operability characteristics of the machine. Further experimentation and analysis is necessary to devise, implement, and verify statistical process control measures.

The Association Of Diet And Physical Activity With Stroke Mortality Results From The Adventist Health Study-1, Tahereh Zamansani

Loma Linda University Electronic Theses, Dissertations & Projects

Stroke is one of the leading causes of death and disability, with major global public health implications. Stroke ranks No. 4 among all causes of death, behind heart disease, cancer, and chronic lower respiratory disease (CLRD). Stroke accounts for almost 1 of every 18 deaths in the United States. Women accounted for 60.6% of stroke deaths. Death certificate data show that the mean age at stroke death was 79.6 years; males had a younger mean age (76.3) than females.

There is still a great scientific uncertainty among researchers and epidemiologists about the magnitude of any preventive effect, mechanisms of action …

Inflammatory Findings On Species Extrapolations: Humans Are Definitely No 70-Kg Mice, Marcel Leist, Thomas Hartung

Validation of Alternative Methods Collection

Modern toxicology has embraced in vitro methods, and major hopes are based on the Omics technologies and systems biology approaches they bring along (Hartung and McBride in ALTEX 28(2):83–93, 2011; Hartung et al. in ALTEX 29(2):119–28, 2012). A culture of stringent validation has been developed for such approaches (Leist et al. in ALTEX 27(4):309–317, 2010; ALTEX 29(4):373–88, 2012a; Toxicol Res 1:8–22, 2012b), while the quality and usefulness of animal experiments have been little scrutinized. A new study (Seok et al. 2013) now shows the low predictivity of animal responses in the field of inflammation. These findings corroborate earlier findings from …

A Comparative Study Of Exact Versus Propensity Matching Techniques Using Monte Carlo Simulation, Mukaria J. J. Itang'ata

Dissertations

Often researchers face situations where comparative studies between two or more programs are necessary to make causal inferences for informed policy decision-making. Experimental designs employing randomization provide the strongest evidence for causal inferences. However, many pragmatic and ethical challenges may preclude the use of randomized designs. In such situations, subject matching provides an alternative design approach for conducting causal inference studies. This study examined various design conditions hypothesized to affect matching procedures’ bias recovery ability.

See attachment for full abstract.

Food For Thought … Mechanistic Validation, Thomas Hartung, Sebastian Hoffman, Martin Stephens

Experimentation Collection

Validation of new approaches in regulatory toxicology is commonly defined as the independent assessment of the reproducibility and relevance (the scientific basis and predictive capacity) of a test for a particular purpose. In large ring trials, the emphasis to date has been mainly on reproducibility and predictive capacity (comparison to the traditional test) with less attention given to the scientific or mechanistic basis. Assessing predictive capacity is difficult for novel approaches (which are based on mechanism), such as pathways of toxicity or the complex networks within the organism (systems toxicology). This is highly relevant for implementing Toxicology for the 21st …

Initiation And Continuation Of Randomized Trials After The Publication Of A Trial Stopped Early For Benefit Asking The Same Study Question: Stopit-3 Study Design, Gabriela J. Prutsky, Juan Domecq, Patricia J. Erwin, Matthias Briel, Victor M. Montori, Elie A. Akl, Joerg J. Meerpohl, Dirk Bassler, Stefan Schandelmaier, Stephen D. Walter, Qi Zhou, Pablo Coello, Lorenzo Moja, Martin Walter, Kristian Thorlund, Paul Glasziou, Regina Kunz, Ignacio Ferreira-Gonzalez, Jason Busse, Xin Sun, Annette Kristiansen, Benjamin Kasenda, Osama Qasim-Agha, Gennaro Pagano, Hector Pardo-Hernandez, Gerard Urrutia, Mohammad Murad, Gordon Guyatt

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Randomized control trials (RCTs) stopped early for benefit (truncated RCTs) are increasingly common and, on average, overestimate the relative magnitude of benefit by approximately 30%. Investigators stop trials early when they consider it is no longer ethical to enroll patients in a control group. The goal of this systematic review is to determine how investigators of ongoing or planned RCTs respond to the publication of a truncated RCT addressing a similar question.

Methods/design

We will conduct systematic reviews to update the searches of 210 truncated RCTs to identify similar trials ongoing at the time of publication, or started …

Asymptotic Behavior Of A T Test Robust To Cluster Heterogeneity, Douglas G. Steigerwald

Douglas G. Steigerwald

We study the behavior of a cluster-robust t statistic and make two principle contributions. First, we relax the restriction of previous asymptotic theory that clusters have identical size, and establish that the cluster-robust t statistic continues to have a Gaussian asymptotic null distribution. Second, we determine how variation in cluster sizes, together with other sources of cluster heterogeneity, affect the behavior of the test statistic. To do so, we determine the sample specific measure of cluster heterogeneity that governs this behavior and show that the measure depends on how three quantities vary over clusters: cluster size, the cluster specific error …