A framework for estimating probability of a match in forensic bite mark identification

In forensic dentistry, a human expert typically does the comparison and identification based on bite marks. Unlike DNA analysis, however, there is no quantitative basis with which to assign a probability for this given match. This paper proposes a framework for empirically estimating the probability of such a bite mark match and reports on initial experimental results. The methodology involved collection of dental population data (3D dental casts and bite mark images), image analysis for quantitatively measuring the degree of match (based on chamfer distance), and performing a logistic regression analysis using the collected population data to estimate the probability of match from the calculated degree of match. The model correctly predicted 35 of the 42 matches and 585 of the 588 mismatches. The method also has potential for use in other forensic applications in which the assignment of quantitative probabilities is important.     

Coasean markets

Coase’s work emphasized the economic importance of very small markets and made a new, more marginalist form of economic “institutionalism” acceptable within mainstream economics. A Coasean market is an association of persons with competing claims on a legal entitlement that can be traded. The boundaries of both Coasean markets and Coasean firms are determined by measuring not only the costs of bargaining but also the absolute costs of moving resources from one place to another. The boundaries of a Coasean market, just as those of the Coasean business firm, are defined by the line where the marginal cost of reaching a value-maximizing bargain by trading inside just equals the marginal cost of going outside. This focus on very small markets is a defining characteristic of modern Transaction Cost Economics. In analyzing such markets Coase ignored the eclectic, historical and behaviorist approach of the old institutionalists and applied the greater formalism and of marginal analysis. In the process, however, Coase assumed away important issues that the first generation of institutionalists were trying to address and created some new ones, such as how equilibrium is attained in Coasean as opposed to neoclassical markets. The most important difference between the two is that a Coasean market requires the unanimous consent of all participants before a trade can be made—a condition imposed by Coase’s own requirement of reciprocity, developed in The Problem of Social Cost (J Law Econ 3:1, 1960). The equilibrium problem is substantial but its significance has not been sufficiently developed. As a result, Coasean analysis of the business firm has made much more progress than has Cosean analysis of markets for legal entitlements. Further, the superiority of private governance over legislation, an important attribute of Coase’s argument, loses much of its force as the number of participants in Coasean markets increases beyond two. Research on the management of commons resources has contributed greatly to our understanding of when private resource allocation decisions by larger groups of owners succeed and when they fail. While not all common resources markets are of the kind contemplated by Coase they share many relevant characteristics. Further, the economic literature on private governance arrangements for the commons has found it necessary to step beyond the strict marginalist methodologies of Coasean economics and look more broadly to the historical, biological and social motivations for human cooperation.     

On Gerasimov's plastic facial reconstruction technique: new insights to facilitate repeatability

Gerasimov's plastic facial reconstruction method is notoriously difficult to repeat from the published literature. Primarily, this is because of the method's underlying qualitative basis but other factors contribute including: misreports in the secondary literature of Gerasimov's method essence; a lack of published details concerning Gerasimov's modeling mastic; Gerasimov's deviation from his own published nose projection prediction guidelines; and continued refinement of the methods in the 15 years following their foremost publication. As Gerasimov cannot be consulted to resolve these issues, we provide solutions via one of his five former principal students. This includes clarification of Gerasimov's method and use of soft tissue depths; the constitution of his modeling mastic; methods used for nose projection prediction; and refinements made to his methods following their primary publication.     

An unusual case of random fire-setting behavior associated with lacunar stroke

A case of a 47-year-old man with a sudden onset of a bizarre and random fire-setting behavior is reported. The man, who had been arrested on felony arson charges, complained of difficulties concentrating and of recent memory impairment. Axial T1-weighted magnetic resonance imaging showed a low intensity lacunar lesion in the genu and anterior limb of the left internal capsule. A neuropsychological test battery revealed lower than normal scores for executive functions, attention and memory, consistent with frontal lobe dysfunction. The recent onset of fire-setting behavior and the chronic nature of the lacunar lesion, together with an unremarkable performance on tests measuring executive functions two years prior, suggested a causal relationship between this organic brain lesion and the fire-setting behavior. The present case describes a rare and as yet unreported association between random impulse-driven fire-setting behavior and damage to the left internal capsule and suggests a disconnection of frontal lobe structures as a possible pathogenic mechanism.