Locating,Identifying, and Comparing Sub‐visible Paint Particles

Forensic paint comparisons are generally conducted on samples which, while small relative to their source, are still visible to the unaided eye and are thus located and analyzed without great difficulty. Here we demonstrate that a more detailed examination of candidate transfer surfaces can capture materials (questioned samples), even when such traces are invisible to the unaided eye. While certain analytical details (such as layer sequence or a pure FTIR spectrum) may not be obtainable from such traces due to their size and condition, a detailed analysis of the sample characteristics that are analytically accessible may still provide sufficient analytical data to arrive at a probative result. Here we present the application of this approach to a suspected paint transfer case, involving particles of paint as small as 40 μm in size. Using a combination of stereomicroscopy, polarized light microscopy, infrared microspectroscopy, Raman microspectroscopy, and SEM/EDS, all performed on a single, subsample of the original minute particle, it was possible to demonstrate evidence of a two‐way transfer between the suspected sources. Furthermore, the transferred paint particle in one direction could be classified as automotive in nature based on a combination of polymer composition, microscopic texture, and pigment package (which included three specifically identified pigments). This work demonstrates (i) the potential for improving detection limits when searching for a questioned sample, (ii) the potential benefits of higher resolution analyses on samples that would be traditionally labeled as “sample‐size limited,” and (iii) the value of case‐specific interpretation over standardized, one‐size fits all report templates.     

“The Train Has Left the Station”: The Project on Emerging Nanotechnologies and the Shaping of Nanotechnology Policy in the United States

The purpose of this paper is to analyze the efforts of the Project on Emerging Nanotechnologies (PEN) in seeking to influence nanotechnology policy in the United States. Using the conceptual framework of anticipatory governance to guide the analysis, a series of strategies that PEN adopted will be described, including leveraging external expertise, developing cross‐disciplinary research products, providing a future‐oriented view on policy analysis, and building a brand for communications and outreach. This case study is a useful example in demonstrating the recent conceptual shift away from relying on government‐led technology assessment efforts to consider the longer‐term implications of new technologies toward the concept of anticipatory governance that includes a more substantive role for nongovernmental actors, that in providing forward‐looking, actionable intelligence for decision makers. Considering the example of PEN also highlights the critical role that boundary‐spanning organizations play in linking together disparate communities of expertise.     

Taking Fact-Checks Literally But Not Seriously? The Effects of Journalistic Fact-Checking on Factual Beliefs and Candidate Favorability

Political Behavior - Are citizens willing to accept journalistic fact-checks of misleading claims from candidates they support and to update their attitudes about those candidates? Previous studies...     

Marching at the Pace of the Slowest: a Model of International Climate-Change Negotiations

We model international negotiations on climate change. Leaders such as the European Union and the US can make proposals and influence veto players, including other countries and domestic lobbies, who must choose whether to accept or reject proposals. We explain why policy change has been minimal in this issue area, which veto-players receive the greatest and least attention and why leader actors wishing to see less progress are in such a strong bargaining position     

Applications of Blue Light‐curing Acrylic Resin to Forensic Sample Preparation and Microtomy

This study discusses the results of an evaluation of a one‐part blue light‐curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light‐curing acrylic resins provide the desired properties of an embedding medium, generate high‐quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory.