2005). Testing for adventitious presence of transgenic material in conventional seed or grain lots using quantitative laboratory methods: statistical procedures and their implementation. AbstractWhen the laboratory methods employed are qualitative, the statistical methodologies used in testing for the adventitious presence (AP) of transgenic material in conventional seed and grain lots are well defined. However, when the response from the method used by the laboratory is quantitative (e.g. percent transgenic DNA), the statistical methodologies developed for qualitative laboratory methods are not fully appropriate. In this paper, we present the details of procedures specific to quantitative laboratory methods. In particular we consider: (1) the assessment of quantitative laboratory method errors using linear modelling; and (2) the process of deciding whether or not a lot meets pre-specified purity standards, including the development of probability calculations needed to develop operating characteristic curves and estimate consumer and producer risks for a given lower quality limit (LQL), acceptable quality limit (AQL) and testing plan. We also describe implementation of this approach in a useful spreadsheet application.

Iron oxide pigments found in archaeological context constitute an important source of information for the understanding of cultural and subsistence activities of ancient human cultures. In order to complete archaeological contextual information, many analytical methods have been applied to characterise pigments and to provide further information on this material (e.g. supplies, selections, mechanical or physical transformations of raw material, use and application processes). Several studies have demonstrated that the elemental composition of iron oxide pigments can be used to discriminate between several geological provenances. In this study, non-destructive micro-particle induced Xray emission analysis was applied in order to distinguish different kinds of reddish pigments from the prehistoric site of Abri Pataud, more especially from the Layer 2 attributed to Final Gravettian period (22,000 BP). By using an external beam, this technique required no sampling, and enabled us to perform localised analyses directly on raw material, on ochre residues applied on artefacts or on fragments of the wall of this rock-shelter. The results obtained by this technique demonstrate that the pigments covering the decorated fragments of the rock-shelter wall, found during the excavation of the Layer 2, have elemental compositions similar to the composition of a raw pigment found in the same layer. These results suggest that the shelter was decorated during the Final Gravettian period and thus provide new insights for the understanding of the archaeological context of this occupation layer.