David Marker

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In this study we estimated the number of housing units in the United States with lead-based paint and lead-based paint hazards. We included measurements of lead in intact and deteriorated paint, interior dust, and bare soil. A nationally representative, random sample of 831 housing units was evaluated in a survey between 1998 and 2000; the units and their(More)
From July 1998 to August 1999, the U.S. Department of Housing and Urban Development and the National Institute of Environmental Health Sciences conducted the first National Survey of Lead and Allergens in Housing. The purpose of the survey was to assess children's potential household exposure to lead, allergens, and bacterial endotoxins. We surveyed a(More)
Using relativizations of results of Goncharov and Peretyat'kin on decidable homogeneous models, we prove that if M is S-saturated for some Scott set S, and F is an enumeration of S, then M has a presentation recursive in F. Applying this result we are able to classify degrees coding (i) the reducts of models of PA to addition or multiplication, (ii)(More)
This article surveys the model theory of differentially closed fields, an interesting setting where one can use model-theoretic methods to obtain algebraic information. The article concludes with one example showing how this information can be used in diophantine applications. A differential field is a field K equipped with a derivation δ : K → K; recall(More)
This article introduces some of the basic concepts and results from model theory, starting from scratch. The topics covered are be tailored to the model theory of fields and later articles. I will be using algebraically closed fields to illustrate most of these ideas. The tools described are quite basic; most of the material is due either to Alfred Tarski(More)