Electron redistribution is the cornerstone of our understanding of chemical reactivity. For the vast majority of organic reactions electrons are assumed to move in pairs providing explanatory mechanisms through the generation of intermediate structures. But for many transformations these discrete steps are idealized constructs, involving intermediates assumed but not empirically justified. This unitary perspective predicated on the curved arrow formalism has resulted in the scenario where for many organic transformations our supposed understanding far surpasses our growing knowledge. Reformulating organic mechanisms (...) to include single electron transfer as a component of, or an alternative to, the prevailing iconic descriptions can provide for a more empirically adequate mechanistic description. In addition using the language of SET presents an opportunity to unify mechanistic concepts under a common donor/acceptor framework. (shrink)

Three experiments explored the effects of word problem cueing on debiasing versions of the bat-and-ball problem. In the experimental condition order, participants solved a simpler isomorphic version of the problem prior to solving a standard version that, critically, had the same item-and-dollar amounts. Conversely, in the control condition order, participants solved the standard version prior to solving the isomorph. Across the first 2 experiments, participants cued with the isomorph were more likely to correctly solve the standard version of the problem. (...) In the third experiment, this cueing effect was not replicated, but importantly cued participants were more likely to correctly solve the standard version of the problem with other item-and-dollar amounts, indicating near transfer. Far transfer was evident in faster response times to other problems in the Cognitive Reflection Test following practice. Along with providing converging evidence for the cueing account, these results are consistent with recent attentional debiasing findings. (shrink)

Heisenberg’s explanation of how two coupled oscillators exchange energy represented a dramatic success for his new matrix mechanics. As matrix mechanics transmuted into wave mechanics, resulting in what Heisenberg himself described as …an extraordinary broadening and enrichment of the formalism of the quantum theory , the term resonance also experienced a corresponding evolution. Heitler and London’s seminal application of wave mechanics to explain the quantum origins of the covalent bond, combined with Pauling’s characterization of the effect, introduced resonance into the (...) chemical lexicon. As the Valence Bond approach gave way to a soon-to-be dominant Molecular Orbital method, our understanding of the term resonance, as it might apply to our understanding the chemical bond, has also changed. (shrink)

Objectives: to assess physicians’ and patients’ views in Saudi Arabia towards involving the patient versus the family in the process of diagnosis disclosure and decision-making, and to compare them with views from the USA and Japan.Design: A self-completion questionnaire was translated to Arabic and validated.Participants: Physicians from different specialties and ranks and patients in a hospital or attending outpatient clinics from 6 different regions in KSA.Results: In the case of a patient with incurable cancer, 67% of doctors and 51% of (...) patients indicated that they would inform the patient in preference to the family of the diagnosis . Assuming the family already knew, 56% of doctors and 49% of patients would tell the patient even if family objected . However, in the case of HIV infection, 59% of physicians and 81% of patients would inform the family about HIV status without the patient’s consent . With regards to withholding ventilatory support, about 50% of doctors and over 60% of patients supported the use of mechanical ventilation in a patient with advanced cancer, regardless of the wishes of the patient or the family. Finally, the majority of doctors and patients were against assisted suicide.Conclusions: Although there was more recognition for a patient’s autonomy amongst physicians, most patients preferred a family centred model of care. Views towards information disclosure were midway between those of the USA and Japan. Distinctively, however, decisions regarding life prolonging therapy and assisted suicide were not influenced to a great extent by wishes of the patient or family, but more likely by religious beliefs. (shrink)

The spin-statistics connection has been proved for nonrelativistic quantum mechanics . The proof is extended here to the relativistic regime using the parametrized Dirac equation. A causality condition is not required.

The aim of this short note is to highlight a possible, hitherto unnoticed, telestich in Verg. Aen. 8.246–9, which presents the Greek word sēma (‘portent’, ‘wonder’, ‘prodigy’, ‘tomb’). To justify this identification, I will argue for its significance from its context in the poem (the battle between Hercules and Cacus), pointing out the insistence on the imagery of light and revelation, and the use of the phrase mirabile dictu, which appears in the same episode of the Aeneid, in the Latin (...) poetic tradition. (shrink)