141,433 research outputs found
Automated identification of Fos expression
The concentration of Fos, a protein encoded by the immediate-early gene c-fos, provides a measure of synaptic activity that may not parallel the electrical activity of neurons. Such a measure is important for the difficult problem of identifying dynamic properties of neuronal circuitries activated by a variety of stimuli and behaviours. We employ two-stage statistical pattern recognition to identify cellular nuclei that express Fos in two-dimensional sections of rat forebrain after administration of antipsychotic drugs. In stage one, we distinguish dark-stained candidate nuclei from image background by a thresholding algorithm and record size and shape measurements of these objects. In stage two, we compare performance of linear and quadratic discriminants, nearest-neighbour and artificial neural network classifiers that employ functions of these measurements to label candidate objects as either Fos nuclei, two touching Fos nuclei or irrelevant background material. New images of neighbouring brain tissue serve as test sets to assess generalizability of the best derived classification rule, as determined by lowest cross-validation misclassification rate. Three experts, two internal and one external, compare manual and automated results for accuracy assessment. Analyses of a subset of images on two separate occasions provide quantitative measures of inter- and intra-expert consistency. We conclude that our automated procedure yields results that compare favourably with those of the experts and thus has potential to remove much of the tedium, subjectivity and irreproducibility of current Fos identification methods in digital microscopy
lawstat: An R Package for Law, Public Policy and Biostatistics
We present a new R software package lawstat that contains statistical tests and procedures that are utilized in various litigations on securities law, antitrust law, equal employment and discrimination as well as in public policy and biostatistics. Along with the well known tests such as the Bartels test, runs test, tests of homogeneity of several sample proportions, the Brunner-Munzel tests, the Lorenz curve, the Cochran-Mantel-Haenszel test and others, the package contains new distribution-free robust tests for symmetry, robust tests for normality that are more sensitive to heavy-tailed departures, measures of relative variability, Levene-type tests against trends in variances etc. All implemented tests and methods are illustrated by simulations and real-life examples from legal cases, economics and biostatistics. Although the package is called lawstat, it presents implementation and discussion of statistical procedures and tests that are also employed in a variety of other applications, e.g., biostatistics, environmental studies, social sciences and others, in other words, all applications utilizing statistical data analysis. Hence, name of the package should not be considered as a restriction to legal statistics. The package will be useful to applied statisticians and "quantitatively alert practitioners" of other subjects as well as an asset in teaching statistical courses.
Perception of Biostatistics by Lebanese Medical Students: A Cross-Sectional Study
Background: Inadequate use of statistics in biomedical research might not only affect science but also harm human beings if applied in medical practice. Biostatistics is fundamental to improve understanding and appraising of evidence-based medicine (EBM); yet, it is still not well understood and appreciated by medical students. Therefore, early exposure of medical students and physicians-in-training to research tools including Biostatistics is of utmostimportance.Objective: The aim of this study is to determine the perception of Biostatistics by medical students at a private medical school in Beirut, Lebanon, and to identify its best implementation time in the medical curriculum.Methods: This is a cross-sectional study based on a self-administered questionnaire distributed among medical students in their pre-clerkship years (first three years of a 6-year program) who undertook Biostatistics. The assessment of perception was based on the 5-point Likert scale anchored by Strongly disagree = 1 and Strongly agree = 5 including 36 questions distributed into four domains to assess the course value, difficulty, behavioral, and expectations.Results: 186 of 269 students responded to the questionnaire, yielding a response rate of 69.14%. Around 60% of students declared that the knowledge gained from biostatistics courses is useful to their future career, and almost 70% understood the main concepts of biostatistics. 57.7% of students perceived that lack of practicing exercises might contribute to making the course more difficult. The mean score of domains was higher in females but did not significantly differ within the three academic years. Only 35.1% of the students positively perceived the importance of biostatistics modules, mostly third-year students.Conclusion: Although the majority of medical students perceived biostatistics modules negatively, they were aware of the relevance of biostatistics to their medical career and real-life health issues
Workshop report: building biostatistics capacity in Sub-saharan Africa-taking action
To address the need for capacity development in biostatistics in the Sub-Saharan African region and to move recommendations from previous workshops into action, we brought together biostatisticians from the region to provide an opportunity to brainstorm biostatistics capacity development in Africa, how to enhance what is being done and establish collaborative links to work together. In order to move key recommendations forward working groups were established to focus on the structure and content of a MSc Biostatistics and on the development of a concept paper for an Africa Centre for Biostatistics Excellence.Pan African Medical Journal 2015; 2
Biostatistics News
Georgia Southern Examines a More Efficient Logistic Analysi
Biostatistics/Epidemiology
Presentations Included:
Spatial Analysis of West Nile Virus Infection Status on Mosquitos & Land Coverage in the US, 2008-2015 Cali Anderson
Trend of Measles Incidence in Africa from 2008 to 2018: A Pooled Analysis of Evidence From 50 WHO-Member States Ogbeide John Inetianbor
Comparability of Data on Infant and Young Child Feeding Indicators between Centers for Disease Control and Prevention and World Health Organization Approaches T.M. Edwards
Characteristics of High-Risk Areas for Colorectal Cancer Mortality in Southeastern Virginia A. Detki, E. Varvil, and H. Galadim
The CTL’s Research Support Newsletter (Summer 2019)
New Resources EndNote Nature Protocols
Grants & Funding Open Access Publishing Fund Pivot
Citation Tools EndNote F1000 RefWorks
Statistical Tools NVivo SOSS Division of Biostatistics
Support Library consultations Office for Writing, Publishing, and Communication Photographers, Graphic Designers, and Videographers Jefferson Digital Commons
Events Lab Archives for Beginners: Professional Edition (Virtual) Lab Archives for Beginners: Classroom Edition (Virtual) Roadmap to Clinical Researc
Deep determinism and the assessment of mechanistic interaction between categorical and continuous variables
Our aim is to detect mechanistic interaction between the effects of two
causal factors on a binary response, as an aid to identifying situations where
the effects are mediated by a common mechanism. We propose a formalization of
mechanistic interaction which acknowledges asymmetries of the kind "factor A
interferes with factor B, but not viceversa". A class of tests for mechanistic
interaction is proposed, which works on discrete or continuous causal
variables, in any combination. Conditions under which these tests can be
applied under a generic regime of data collection, be it interventional or
observational, are discussed in terms of conditional independence assumptions
within the framework of Augmented Directed Graphs. The scientific relevance of
the method and the practicality of the graphical framework are illustrated with
the aid of two studies in coronary artery disease. Our analysis relies on the
"deep determinism" assumption that there exists some relevant set V - possibly
unobserved - of "context variables", such that the response Y is a
deterministic function of the values of V and of the causal factors of
interest. Caveats regarding this assumption in real studies are discussed.Comment: 20 pages including the four figures, plus two tables. Submitted to
"Biostatistics" on November 24, 201
Biostatistics News
Georgia Southern: Examines Estimation of P (X \u3e Y) when X and Y are Dependent Random Variable
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