Relative Quenching Cross Sections in the Reaction of Hg(63P1) Atoms with Isotopic N2O Molecules

The N14/N15 and O16/O18 isotope effects in the Hg(63P1)‐photosensitized decomposition of nitrous oxide have been measured. Observed isotopic fractionation factors, S0 (interpreted in terms of ratios of rate constants for quenching by N14N14O16 vs N15N14O16, N14N15O16, and N14N14O18), are related to the ratio of isotopic quenching cross sections by the equation Q/Q*=S0(μ/μ*)☒, where μ and μ* are the collisional reduced masses for Hg and the light and heavy isotopic molecules, respectively. The quenching cross section ratio for N142O16/N142O18 was unity within the experimental uncertainty (±0.1%). The ratios for N14N14O16/N15N14O16 and N14N14O16/N14N15O16 differed from unity by +0.98 and +0.44%, respectively. The order of the quenching cross sections for the isotopic nitrous oxide molecules is thus: N15N14O16<N14N15O16<14N14O18≅N14N14O16. The implications of the present observations are briefly discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69865/2/JCPSA6-33-2-526-1.pd

Decoding Guilty Minds

A central tenet of Anglo-American penal law is that in order for an actor to be found criminally liable, a proscribed act must be accompanied by a guilty mind. While it is easy to understand the importance of this principle in theory, in practice it requires jurors and judges to decide what a person was thinking months or years earlier at the time of the alleged offense, either about the results of his conduct or about some elemental fact (such as whether the briefcase he is carrying contains drugs). Despite the central importance of this task in the administration of criminal justice, there has been very little research investigating how people go about making these decisions, and how these decisions relate to their intuitions about culpability. Understanding the cognitive mechanisms that govern this task is important for the law, not only to explore the possibility of systemic biases and errors in attributions of culpability but also to probe the intuitions that underlie them. In a set of six exploratory studies reported here, we examine the way in which individuals infer others’ legally relevant mental states about elemental facts, using the framework established over fifty years ago by the Model Penal Code (“MPC”). The widely adopted MPC framework delineates and defines the four now-familiar culpable mental states: purpose, knowledge, recklessness, and negligence. Our studies reveal that with little to no training, jury-eligible Americans can apply the MPC framework in a manner that is largely congruent with the basic assumptions of the MPC’s mental state hierarchy. However, our results also indicate that subjects’ intuitions about the level of culpability warranting criminal punishment diverge significantly from prevailing legal practice; subjects tend to regard recklessness as a sufficient basis for punishment under circumstances where the legislatures and courts tend to require knowledge

Mutational analysis of βCOP (Sec26p) identifies an appendage domain critical for function

<p>Abstract</p> <p>Background</p> <p>The appendage domain of the γCOP subunit of the COPI vesicle coat bears a striking structural resemblance to adaptin-family appendages despite limited primary sequence homology. Both the γCOP appendage domain and an equivalent region on βCOP contain the FxxxW motif; the conservation of this motif suggested the existence of a functional appendage domain in βCOP.</p> <p>Results</p> <p>Sequence comparisons in combination with structural prediction tools show that the fold of the COOH-terminus of Sec26p is strongly predicted to closely mimic that of adaptin-family appendages. Deletion of the appendage domain of Sec26p results in inviability in yeast, over-expression of the deletion construct is dominant negative and mutagenesis of this region identifies residues critical for function. The ArfGAP Glo3p was identified via suppression screening as a potential downstream modulator of Sec26p in a manner that is independent of the GAP activity of Glo3p but requires the presence of the COOH-terminal ISS motifs.</p> <p>Conclusion</p> <p>Together, these results indicate an essential function for the predicted βCOP appendage and suggest that both COPI appendages perform a biologically active regulatory role with a structure related to adaptin-family appendage domains.</p

Parsing the Behavioral and Brain Mechanisms of Third-Party Punishment

The evolved capacity for third-party punishment is considered crucial to the emergence and maintenance of elaborate human social organization and is central to the modern provision of fairness and justice within society. Although it is well established that the mental state of the offender and the severity of the harm he caused are the two primary predictors of punishment decisions, the precise cognitive and brain mechanisms by which these distinct components are evaluated and integrated into a punishment decision are poorly understood. Using a brain-scanning technique known as functional magnetic resonance imaging (fMRI), we implemented a novel experimental design to functionally dissociate the mechanisms underlying evaluation, integration, and decision. This work revealed that multiple parts of the brain – some analytic, some subconscious or emotional – work in a systematic pattern to decide blameworthiness, assess harms, integrate those two decisions, and then ultimately select how a person should be punished. Specifically, harm and mental state evaluations are conducted in two different brain networks and then combined in the medial prefrontal and posterior cingulate areas of the brain, while the amygdala acts as a pivotal hub of the interaction between harm and mental state. This integrated information is then used by the right dorsolateral prefrontal cortex when the brain is making a decision on punishment amount. These findings provide a blueprint of the brain mechanisms by which neutral third parties make punishment decisions

Parsing the Behavioral and Brain Mechanisms of Third-Party Punishment.

UnlabelledThe evolved capacity for third-party punishment is considered crucial to the emergence and maintenance of elaborate human social organization and is central to the modern provision of fairness and justice within society. Although it is well established that the mental state of the offender and the severity of the harm he caused are the two primary predictors of punishment decisions, the precise cognitive and brain mechanisms by which these distinct components are evaluated and integrated into a punishment decision are poorly understood. Using fMRI, here we implement a novel experimental design to functionally dissociate the mechanisms underlying evaluation, integration, and decision that were conflated in previous studies of third-party punishment. Behaviorally, the punishment decision is primarily defined by a superadditive interaction between harm and mental state, with subjects weighing the interaction factor more than the single factors of harm and mental state. On a neural level, evaluation of harms engaged brain areas associated with affective and somatosensory processing, whereas mental state evaluation primarily recruited circuitry involved in mentalization. Harm and mental state evaluations are integrated in medial prefrontal and posterior cingulate structures, with the amygdala acting as a pivotal hub of the interaction between harm and mental state. This integrated information is used by the right dorsolateral prefrontal cortex at the time of the decision to assign an appropriate punishment through a distributed coding system. Together, these findings provide a blueprint of the brain mechanisms by which neutral third parties render punishment decisions.Significance statementPunishment undergirds large-scale cooperation and helps dispense criminal justice. Yet it is currently unknown precisely how people assess the mental states of offenders, evaluate the harms they caused, and integrate those two components into a single punishment decision. Using a new design, we isolated these three processes, identifying the distinct brain systems and activities that enable each. Additional findings suggest that the amygdala plays a crucial role in mediating the interaction of mental state and harm information, whereas the dorsolateral prefrontal cortex plays a crucial, final-stage role, both in integrating mental state and harm information and in selecting a suitable punishment amount. These findings deepen our understanding of how punishment decisions are made, which may someday help to improve them