The goals, achievements, and tools of modern geodesy

Today, Geodesy is the science of determining the geometry, gravity field, and rotation of the Earth and their evolution in time. Geodesy in increasingly forced not only to "measure" the geokinematics, gravity field, and rotation, but also to "model" these quantities on the basis of mass transport and dynamics. The instruments (or measurement tools) are of crucial importance in geodesy

Functional assessment and challenging behaviors: some future directions

Behavior analysts have had a significant impact on the analysis and intervention of challenging behaviors in persons with developmental disabilities. These successes are celebrated in the first part of this article. In the remainder of the article, we present a selective discussion of three issues that we hope will help to further stimulate work with challenging behaviors: (a) the development of challenging behaviors, (b) the role of rule-governance in challenging behavior, and (c) the behavior of persons (mediators) who directly apply functional assessment and intervention technologies. Each of these issues is discussed and implications are drawn for future reseach and practice in the field. In drawing some conclusions, we focus on the internal and external validity of functional assessment and interventions