Empirical Evaluation

Developing a novel technique for the efficient, noninvasive clinical evaluation of bone microarchitecture remains both crucial and challenging. The trabecular bone score (TBS) is a new gray-level texture measurement that is applicable to dual-energy X-ray absorptiometry (DXA) images. Significant correlations between TBS and standard 3-dimensional (3D) parameters of bone microarchitecture have been obtained using a numerical simulation approach. The main objective of this study was to empirically evaluate such correlations in anteroposterior spine DXA images. Thirty dried human cadaver vertebrae were evaluated. Micro-computed tomography acquisitions of the bone pieces were obtained at an isotropic resolution of 93μm. Standard parameters of bone microarchitecture were evaluated in a defined region within the vertebral body, excluding cortical bone. The bone pieces were measured on a Prodigy DXA system (GE Medical-Lunar, Madison, WI), using a custom-made positioning device and experimental setup. Significant correlations were detected between TBS and 3D parameters of bone microarchitecture, mostly independent of any correlation between TBS and bone mineral density (BMD). The greatest correlation was between TBS and connectivity density, with TBS explaining roughly 67.2% of the variance. Based on multivariate linear regression modeling, we have established a model to allow for the interpretation of the relationship between TBS and 3D bone microarchitecture parameters. This model indicates that TBS adds greater value and power of differentiation between samples with similar BMDs but different bone microarchitectures. It has been shown that it is possible to estimate bone microarchitecture status derived from DXA imaging using TBS.

This paper describes work carried out to explore the role of a learning companion as a teachable student of the human student. A LCS for Binary Boolean Algebra has been developed to explore the hypothesis that a learning companion with less expertise than ...

Dissemination of data with sensitive information about individuals has an implicit risk of unauthorized disclosure. Perturbative masking methods propose the distortion of the original data sets before publication, tackling a difficult tradeoff between data utility (low information loss) and protection against disclosure (low disclosure risk). In this paper, we describe how information loss and disclosure risk measures can be integrated

This paper presents an empirical study investigating the effects of training dataquantity, measurement error, pixel coordinate noise, and the choice of camera model, oncamera calibration accuracy, based on three publicly available techniques, developed byTsai, Heikkilä and Zhang. Results are first provided for asimulated camera system and then verified through carefully controlled experiments using real-world measurements. Our aims are to provide suggestions to researchers who require an immediate solution for camera calibration and a warning of the practical difficulties one may encounter in a real environment. In addition, we offer some insight into the factors to keep in mind when selecting a calibration technique. Finally, we hope that this paper can serve as an introduction to the field for those newly embarking upon calibration-related research.

Attention-deficit/hyperactivity disorder (ADHD) is a lifelong neurodevelopmental disorder in which approximately two thirds of patients experience impairment in adulthood. Although some adults with ADHD were diagnosed as children, many are first diagnosed as adults. This poses particular challenges given the limited familiarity with ADHD of many adult mental health services. As a result, several organizations, including the Canadian ADHD Resource Alliance, the American Academy of Child and Adolescent Psychiatry, the National Institutes of Health, and the British Association for Psychopharmacology, have developed practice guidelines for the assessment and treatment of adults with ADHD. This article reviews those guidelines in order to examine current best practices in adult ADHD. There is considerable agreement among these guidelines, which should be a critical part of moving from emerging knowledge to patient care, although both empirical evaluation and ongoing updates as new knowle...