Measuring Preferences for Divided Government: Some Americans Want Divided Government and Vote to Create It

Political Behavior - Tests of theories of the electoral origins of divided government hinge on the proper measurement of voter preferences for divided government. Deriving preferences for divided...     

Detecting Gunshot Residue from Sellier & Bellot Nontox Heavy Metal‐free Primer by in situ Cathodoluminescence

Gunshot residue (GSR) from the discharge of ammunition can provide crucial information in reconstructing criminal cases. Traditional primers create particles of heavy metals such as lead, barium, and antimony. In forensic laboratories, automatic inorganic particle detection is performed by scanning electron microscopy (SEM), using the backscattered electron signal to search for bright residues among the many darker environmental particles, due to higher electron density of the former. Some innovative primers, indicated as heavy metal‐free (HMF), produce a residue of elements with atomic numbers below 21, urgently demanding new detecting solutions. For the first time, residues from Sellier & Bellot Nontox HMF primer are demonstrated to emit visible light under electron beam stimulation in a SEM. Cathodoluminescence is then proposed as a promising tool to both detect and characterize residues in forensic cases involving HMF primers, with minor changes to traditional analytical apparatus used for inorganic GSR analysis.     

Testing proximity versus directional voting using experiments

A long-running debate about how voters use issues to evaluate candidates pits the proximity theory of voting against directional theory. Using surveys, both sides of the debate have found support for their preferred theory, but disagreement remains because of differing ways of analyzing the data. Lewis and King (2000) point out that these researchers make assumptions that bias results in favor of their theory. To avoid these difficulties, our approach creates fictitious candidates with controlled positions, presents these candidates to randomly-assigned subjects, and examines the relationship between subjects’ evaluations of these candidates and their ideological beliefs as a neutral test of proximity and directional theory. Our results provide reasonably strong support for proximity theory but little for directional theory.     

The rise of the opposition party in Taiwan: explaining Chen Shui-bian’s victory in the 2000 Presidential election

The 2000 Taiwan presidential election drastically changed Taiwan’s political landscape. For the first time in Taiwan, an opposition party candidate, Chen Shui-bian, won the presidential race, receiving 39.3% of the popular vote. To understand the factors that determined the election’s outcome, we analyze survey data from the 2000 presidential election. First, we study whether a divided ruling party was the cause of the opposition party candidate’s victory. That is, would the ruling party have lost if one of the trailing candidates had opted not to run? Second, there were charges following the election that the Kuomintang misled people into believing their candidate was still leading in the polls, when he was really running third, and this misinformation led people to vote differently than they would have otherwise, possibly giving the election to the opposition party candidate. We examine the validity of this claim by measuring the degree to which strategic voting could have influenced the outcome. Third, to understand the underlying dimensions of the electoral competition in Taiwan and to understand each candidate’s electoral support, we run a multivariate statistical model to study how strategic voting, candidate personalities, party identification, and issues influenced respondents’ vote choices. Finally, we discuss the effects of election polling data on election outcomes.     

Maximum Likelihood Estimation of Models with Beta-Distributed Dependent Variables

Research in political science is often concerned with modelingdependent variables that are proportions. Proportions are relevantin a wide variety of substantive areas, including elections,the bureaucracy, and interest groups. Yet because most researchersrely upon an approach, OLS, that does not recognize key aspectsof proportions, the conclusions we reach from normal modelsmay not provide the best understanding of phenomena of interestin these areas. In this paper, I use Monte Carlo simulationsto show that maximum likelihood estimation of these data usingthe beta distribution may provide more accurate and more preciseresults. I then present empirical analyses illustrating someof these differences.     

Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry

The method of sample recovery for trace detection and identification of explosives plays a critical role in several criminal investigations. After bombing, there can be difficulties in sending big objects to a laboratory for analysis. Traces can also be searched for on large surfaces, on hands of suspects or on surfaces where the explosive was placed during preparatory phases (e.g. places where an IED was assembled, vehicles used for transportation, etc.).In this work, triacetone triperoxide (TATP) was synthesized from commercial precursors following reported methods. Several portions of about 6 mg of TATP were then spread on different surfaces (e.g. floors, tables, etc.) or used in handling tests. Three different swabbing systems were used: a commercial swab, pre-wetted with propan-2-ol (isopropanol) and water (7:3), dry paper swabs, and cotton swabs wetted with propan-2-ol. Paper and commercial swabs were also used to sample a metal plate, where a small charge of about 4 g of TATP was detonated. Swabs were sealed in small glass jars with screw caps and Parafilm^® M and sent to the laboratory for analysis. Swabs were extracted and analysed several weeks later by gas chromatography/mass spectrometry. All the three systems gave positive results, but wetted swabs collected higher amounts of TATP. The developed procedure showed its suitability for use in real cases, allowing TATP detection in several simulations, including a situation in which people wash their hands after handling the explosive.     

Estimating the time since discharge of spent cartridges: A logical approach for interpreting the evidence

Estimating the time since discharge of a spent cartridge or a firearm can be useful in criminal situations involving firearms. The analysis of volatile gunshot residue remaining after shooting using solid-phase microextraction (SPME) followed by gas chromatography (GC) was proposed to meet this objective. However, current interpretative models suffer from several conceptual drawbacks which render them inadequate to assess the evidential value of a given measurement. This paper aims to fill this gap by proposing a logical approach based on the assessment of likelihood ratios. A probabilistic model was thus developed and applied to a hypothetical scenario where alternative hypotheses about the discharge time of a spent cartridge found on a crime scene were forwarded. In order to estimate the parameters required to implement this solution, a non-linear regression model was proposed and applied to real published data. The proposed approach proved to be a valuable method for interpreting aging-related data.