3,239 research outputs found
Saturn integrated circuit reliability test program Final report, 28 Jun. 1966 - 1 Jul. 1967
Literature survey and test program to study reliability of linear integrated circuit
Handling uncertainties in background shapes: the discrete profiling method
A common problem in data analysis is that the functional form, as well as the
parameter values, of the underlying model which should describe a dataset is
not known a priori. In these cases some extra uncertainty must be assigned to
the extracted parameters of interest due to lack of exact knowledge of the
functional form of the model. A method for assigning an appropriate error is
presented. The method is based on considering the choice of functional form as
a discrete nuisance parameter which is profiled in an analogous way to
continuous nuisance parameters. The bias and coverage of this method are shown
to be good when applied to a realistic example.Comment: Accepted by J.Ins
Does neighborhood disorder predict recovery from mobility limitation? Findings from the Health and Retirement Study
Objective: This research explores whether perceptions of physical neighborhood disorder predict recovery from mobility limitation over a 2-year period and examines whether psychosocial factors (i.e., depressive symptomology and mastery) and physical activity are salient mediators. Method: Using data from the Health and Retirement Study (HRS): Participant Lifestyle Questionnaire (2008-2010), odds ratio estimates of recovery were ascertained using binary logistic regression, and post hoc Sobel tests were conducted to formally assess mediation. Results: Net of demographic characteristics and socioeconomic status, increased neighborhood disorder was associated with lower odds of recovery. However, both psychosocial indicators and physical activity were significant individual partial mediators, which suggest neighborhood disorder influences recovery from physical impairment via psychosocial processes and barriers to physical activity. Discussion: Reducing neighborhood disorder may enhance older residents’ psychosocial well-being and improve participation in physical activity, thus increasing recovery from mobility limitation and preventing subsequent disability
A study to develop neutron activation for measuring bone calcium content
Neutron activation analysis for measuring calcium in monkey bone
The Upper Limit Solar Gamma-ray Spectrum to 10 Mev
Balloon flight data on upper limit solar gamma ray spectrum from quiet su
Saturn integrated circuit reliability test program Quarterly progress report, Jul. - Sep. 1966
Saturn integrated circuit reliability tests performed to improve failure mode screenin
System Dynamics Modeling for Cancer Prevention and Control: A systematic review
Cancer prevention and control requires consideration of complex interactions between multilevel factors. System dynamics modeling, which consists of diagramming and simulation approaches for understanding and managing such complexity, is being increasingly applied to cancer prevention and control, but the breadth, characteristics, and quality of these studies is not known. We searched PubMed, Scopus, APA PsycInfo, and eight peer-reviewed journals to identify cancer-related studies that used system dynamics modeling. A dual review process was used to determine eligibility. Included studies were assessed using quality criteria adapted from prior literature and mapped onto the cancer control continuum. Characteristics of studies and models were abstracted and qualitatively synthesized. 32 studies met our inclusion criteria. A mix of simulation and diagramming approaches were used to address diverse topics, including chemotherapy treatments (16%), interventions to reduce tobacco or e-cigarettes use (16%), and cancer risk from environmental contamination (13%). Models spanned all focus areas of the cancer control continuum, with treatment (44%), prevention (34%), and detection (31%) being the most common. The quality assessment of studies was low, particularly for simulation approaches. Diagramming-only studies more often used participatory approaches. Involvement of participants, description of model development processes, and proper calibration and validation of models showed the greatest room for improvement. System dynamics modeling can illustrate complex interactions and help identify potential interventions across the cancer control continuum. Prior efforts have been hampered by a lack of rigor and transparency regarding model development and testing. Supportive infrastructure for increasing awareness, accessibility, and further development of best practices of system dynamics for multidisciplinary cancer research is needed
Mapping Mental Models Through an Improved Method for Identifying Causal Structures in Qualitative Data
Qualitative data are commonly used in the development of system dynamicsmodels, but methods for systematically identifying causal structures in qualita-tive data have not been widely established. This article presents a modifiedprocess for identifying causal structures (e.g., feedback loops) that are commu-nicated implicitly or explicitly and utilizes software to make coding, tracking,and model rendering more efficient. This approach draws from existingmethods, system dynamics best practice, and qualitative data analysis tech-niques. Steps of this method are presented along with a description of causalstructures for an audience new to system dynamics. The method is applied to aset of interviews describing mental models of clinical practice transformationfrom an implementation study of screening and treatment for unhealthy alco-hol use in primary care. This approach has the potential to increase rigour andtransparency in the use of qualitative data for model building and to broadenthe user base for causal-loop diagramming
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