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Robert Nelson

Publications and source records attributed to Robert Nelson.

4 recordsLinked to original sources

Extent of Safety Database in Pediatric Drug Development: Types of Assessment, Analytical Precision, and Pathway for Extrapolation through On-Target Effects

Pediatric patients should have access to medicines that have been appropriately evaluated for safety and efficacy. Given this goal of revised labelling, the adequacy of the pediatric clinical development plan and resulting safety database must inform a favorable benefit-risk assessment for the intended use of the medicinal product. While extrapolation from adults can be used to support efficacy of drugs in children, there may be a reluctance to use the same approach in safety assessments, wiping out potential gains in trial efficiency through a reduction of sample size. To address this reluctance, we explore safety review in pediatric trials, including factors affecting these data, specific types of safety assessments, and precision on the estimation of event rates for specific adverse events (AEs) that can be achieved. In addition, we discuss the assessments which can provide a benchmark for the use of extrapolation of safety that focuses on on-target effects. Finally, we explore a unified approach for understanding precision using Bayesian approaches as the most appropriate methodology to describe/ascertain risk in probabilistic terms for the estimate of the event rate of specific AEs.

stat.AP

Visualizing a Large Spatiotemporal Collection of Historic Photography with a Generous Interface

Museums, libraries, and other cultural institutions continue to prioritize and build web-based visualization systems that increase access and discovery to digitized archives. Prominent examples exist that illustrate impressive visualizations of a particular feature of a collection. For example, interactive maps showing geographic spread or timelines capturing the temporal aspects of collections. By way of a case study, this paper presents a new web-based visualization system that allows users to simultaneously explore a large collection of images along several different dimensions---spatial, temporal, visual, textual, and through additional metadata fields including the photographer name---guided by the concept of generous interfaces. The case study is a complete redesign of a previously released digital, public humanities project called Photogrammar (2014). The paper highlights the redesign's interactive visualizations that are now possible by the affordances of newly available software. All of the code is open-source in order to allow for re-use of the codebase to other collections with a similar structure.

cs.HC

Robust Oil-spill Forensics and Petroleum Source Differentiation using Quantized Peak Topography Maps

Identification and classification of environmental forensics, with the petroleum forensics as the main application, requires an effective technology or method to distinguish between the closely located forensics as they share many main biomarkers. Two-dimensional gas chromatography is one of these technologies with which a petroleum forensic is separated into its chemical compounds, resulting in a three-dimensional image, GCXGC image. Therefore, distinguishing between two petroleum forensics is equivalent to the comparison between their corresponding GCXGC images. In this paper, we present a technique, called Quantized Peak Topography Map (QPTM), which results in a better separation between the GCXGC images. We validate our proposed method on a model dataset, consisting of thirtyfour GCXGC images, extracted from the different parts of the world.

eess.SP

Observational Studies of Early-type Overcontact Binaries: TU Muscae

We present new spectroscopic and photometric data on the early-type overcontact binary TU Muscae. The analysis of the spectroscopic data shows that the line of sight to the system crosses three kinematically sharp and well-separated interstellar reddening sources and that the stars rotate synchronously. We present new radial velocities that are in good agreement with earlier optical velocities and, thus, do not confirm the systematically smaller velocities obtained from IUE spectra. The optical velocities are analyzed simultaneously with the photometric data to derive accurate absolute dimesions for the binary components.The results show that TU Mus consists of an O7.5 primary with M_1=23.5 +/- 0.8 M_sun, R_1=7.48 +/- 0.08 R_sun and an O9.5 secondary with M_2=15.3 +/- 0.4 M_sun, R_2=6.15 +/- 0.07 R_sun in an overcontact configuration and that the orbital period has remained constant over the three decades covered by the observations. These results might imply that the mass transfer seen in late-type overcontact binaries does not occur in their early-type counterparts.

astro-ph