Blast Suppression Foam,Aqueous Gel Blocks,and their Effect on Subsequent Analysis of Forensic Evidence*

In addition to having blast mitigation properties, aqueous foam concentrate AFC-380 blast suppression foam is designed to capture aerosolized chemical, biological, and radioactive particles during render-safe procedures of explosive devices. Exposure to aqueous environments and surfactants may negatively affect forensic evidence found at the scene, but the effects of AFC-380 foam and aqueous gel on the preservation and subsequent analysis of forensic evidence have not previously been investigated. Sebaceous finger and palm prints and DNA samples on paper, cardboard, tape, and various metal and plastic items, along with hairs, carpet and yarn fibers, and inks and documents, were exposed to AFC-380 foam. Similar mock evidence was also exposed to a superabsorbent gel of the type found in aqueous gel blocks used for shrapnel containment. Exposure to foam or aqueous gel was associated with a dilution effect for recovered DNA samples, but quality of the samples was not substantially affected. In contrast, exposure to AFC-380 foam or gel was detrimental to development of latent finger and palm prints on any substrate. Neither the hair nor the fiber samples were affected by exposure to either the foam or gel. Indented writing on the document samples was detrimentally affected by foam or gel exposure, but not inks and toners. The results from this study indicate that most types of forensic evidence recovered after being exposed to aqueous gel or blast suppression foam can be reliably analyzed, but latent finger and palm prints may be adversely affected.     

Computer‐Assisted Keyword and Document Set Discovery from Unstructured Text

The (unheralded) first step in many applications of automated text analysis involves selecting keywords to choose documents from a large text corpus for further study. Although all substantive results depend on this choice, researchers usually pick keywords in ad hoc ways that are far from optimal and usually biased. Most seem to think that keyword selection is easy, since they do Google searches every day, but we demonstrate that humans perform exceedingly poorly at this basic task. We offer a better approach, one that also can help with following conversations where participants rapidly innovate language to evade authorities, seek political advantage, or express creativity; generic web searching; eDiscovery; look‐alike modeling; industry and intelligence analysis; and sentiment and topic analysis. We develop a computer‐assisted (as opposed to fully automated or human‐only) statistical approach that suggests keywords from available text without needing structured data as inputs. This framing poses the statistical problem in a new way, which leads to a widely applicable algorithm. Our specific approach is based on training classifiers, extracting information from (rather than correcting) their mistakes, and summarizing results with easy‐to‐understand Boolean search strings. We illustrate how the technique works with analyses of English texts about the Boston Marathon bombings, Chinese social media posts designed to evade censorship, and others.     

When Do Low Roll Rates Indicate Party Influence? Evidence from Counterfactual Roll Rates

A simulation-based counterfactual is one way to solve the observational equivalence challenge that seemingly “partisan” majority-party roll rates can be observed in the absence of any actual party influence. We simulate no-partisan-agenda-control counterfactual roll rates and apply them across sessions of the US House of Representatives and 86 state legislative chambers to evaluate the extent to which observed roll rates provide evidence for party influence on the legislative agenda. After assessing and controlling for the baseline risk of majority-party rolls, there is significant evidence of party influence on roll rates in some state legislatures, particularly those with rules that grant parties more agenda power, and in the post-Reed’s-rules House of Representatives. Institutional rules interact with the (simulated) risk of a majority roll to shape observed roll rates across chambers and across time.     

The unassailable principle: why luther gulick searched for a science of administration

Luther Gulick's two contributions to the Papers on the Science of Administration are often regarded as a statement of the “orthodoxy” in the field of public administration in the pre-war period. This paper challenges this view. It argues that the two basic claims in Gulick's work--the notion that public administration could be considered as a science, and that field could be studied without regard to politics--were widely contested throughout the 1920's and 1930's. Gulick adhered to these claims in part because they were useful in protecting a young and weakly-institutionalized field against powerful critics. By the late 1930's, academics in public administration may have confronted a dilemma: the position staked out by Gulick and others, while essential to the development of the field, was regarded by many within the field as being intellectually untenable.     

Experts and evidence in deliberation: scrutinising the role of witnesses and evidence in mini-publics,a case study

Policy Sciences - Experts hold a prominent position in guiding and shaping policy-making; however, the nature of expert input to decision-making is a topic of public debate. A key aspect of...     

Terrorism Research: Past,Present, and Future

Research on terrorism and counterterrorism draws on many disciplines, including Politics, History, Sociology and Anthropology. Yet there are concerns about scope, methodology, impact, and the level of public debate. An agreed definition of terrorism is unattainable: there should be more focus on particular acts rather than labelling whole movements. The threat of terrorism should be kept in proportion. Understanding its causes, and associated belief-systems, is crucial to conducting effective counterterrorist operations. Evaluations of the effectiveness of both terrorism and counterterrorism need to encompass more factors, including terrorism's deadliest legacies: wars on terror that fail, and a habit of violence.