Regulation of conformational interconversions in symmetric and asymmetric [2]catenanes.

Using non-biasing tethers, consisting of phenyl rings designed to be blocking or non-blocking in nature, we were able to control the pathway for interconversion. Through the appropriate incorporation of blocking groups on one or both of two phenyl tethers it was possible to block one or both of the two pathways for circumrotation in our bistable catenanes. The free energies of activation required for circumrotation over the open, non-blocking pathways were calculated at 11 to 13 kcal/mol. The isomer ratios for these catenanes were 1 to 1 indicating the two conformations were isoenergetic. Using these symmetric catenanes, we demonstrated the ability to dictate the pathway over which circumrotation occurred in a non-covalently bound system.In our studies, we investigated control of molecular motion as it could pertain to the emerging area of molecular machines and ratchets. We based our studies on the movement in mechanically interlocked molecular rings known as catenanes. These [2]catenanes possessed a dibenzo-34-crown-10 ether interlocked with a ring containing two 4,4'-dipyridiniums connected by aryl tethers. These novel catenanes contain bistable binding sites separated and connected by biasing or non-biasing tethers.Using asymmetric, biasing tethers we sought to drive circumrotation preferentially in one direction using a gate that would discriminate between the two conformations. Allosteric interaction between the gate and catenated crown ether would either allow or disallow translocation over the gate based on the direction of circumrotation. The free energies of activation for circumrotation were calculated at 11 to 19 kcal/mol. While two gating catenane systems did appear to display the anticipated characteristics, the results were not convincing and could be attributed to other phenomenon. (Abstract shortened by UMI.)Using asymmetric, non-biasing tethers we determined the extent to which the isomer ratios were dependant on the symmetry of the catenanes, and measured the thermodynamic preference displayed between the two conformers. Circumrotation in these catenanes required between 11 and 15 kcal/mol of energy. We found the conformer stabilities were symmetry dependent displaying isomer ratios of between 1.5:1 and 3.5:1. This indicated that one conformation was more stable

Chapter 5 The ‘hell of modern sound’

Contemporary Japan is loud. Many scholars have argued that the Japanese have a cultural propensity to embrace urban noise. Yet little research has been done on the history of urban noise in Japan. Far from passively accepting or culturally embracing noisy cities, the Japanese have long struggled with the definition, measurement, and control of unwanted sound. Urban noise and the idea of the ‘modern’ soundscape has often worked within a feedback loop that amplifies politically driven debates about the nature of ‘modernity’, the meaning of ‘civilisation’ and the nature of the Japanese people. Since the late nineteenth century, authorities' concern for urban noise stemmed from a fear of embarrassment because of the low-level of ‘civilisation’ amongst the people. Yet rapid industrial development and urban population growth soon posed the problem of urban noise as one of technological expertise-the people were too backward to understand and the issue was best solved by the experts. As groups of scientists, engineers and acousticians began to come together to debate solutions, they foregrounded urban noise as a problem of traffic, transport, and civic construction, not individual everyday life. Noisy neighbours, street noise, or people going about their daily business came to be heard as ‘urban music’ in contrast to ‘urban noise’. After 1945, better technological possibilities for sound proofing and an increasing focus on individual responsibility refocused urban noise as a problem of everyday life. With the end of the period of rapid economic growth in the 1970s, and the growing awareness of wider environmental problems, the noise of everyday life in the cities was gradually recast as one element of ‘urban noise’

Contract Norms and Contract Enforcement in Graeco-Roman Egypt

This dissertation explores the ethics and norms associated with contracting in Ptolemaic and Roman Egypt as a contribution to the institutional study of ancient contract and its relationship to the economic history of the Roman world. Although ancient contracts in the Hellenistic tradition (i.e., non-Roman law contracts) have been studied rigorously from a legal perspective, there has been no systematic study of contract as an economic institution in the eastern half of the ancient Mediterranean. The first three chapters argue that such a study is a historical desideratum and seek to establish the theoretical and methodological basis and scope of such a project. Theoretically, the most decisive factor in determining the nature, extent, and success of contract as an economic institution is actual enforcement, as opposed to mere legal "enforceability." While the modern (Western) state has been justly credited with having had a transformative effect on contract by publishing clear rules (i.e., contract law) and providing effective "third-party" enforcement, even modern contracts depend on the enforcement activities of the individual parties and the power of social norms. Historically, there is no question that the ancient state, Rome included, was less invested and less effective in its support and promotion of private contracting than its modern counterparts. Ethics and norms therefore played a larger and more important role in ancient contracting than they have in the last century and as such need to be studied in their own right. The nature of the project also argues for Egypt being the primary locus of study, since the papyri afford us the most complete access to ancient individuals and organizations using contracts to organize transactions. After the theoretical and methodological discussion, there follow explorations of several important social values and norms with respect to contracting in Graeco-Roman Egypt, including trust (pistis), "respect" (eugnōmosynē), and "breach." The results show how "personal" contracting was and reveal some of the ways in which individuals bridged the inevitable "trust gaps" in their efforts to build credible commitments with those outside the immediate circle of their trusted intimates. It also illuminates the discourse of reputation, a key lever in ancient contract formation and enforcement. Finally, the notion of breach is shown to have become both more common and to have evolved conceptually in written contracts over time. It is argued that these changes in the idea and drafting of breach should be interpreted in light of a larger pattern of historical and legal development spanning the second century BCE to the second century CE, a period which witnessed an increasing "moralization" of contract, itself an adaptation to an enforcement regime heavily dependent on ethics and norms. The last chapter offers a synthesis of the findings and a prospectus of the next phase of the project, which turns to the role of the state, arguing that it was generally more effective and activist than the current opinion allows

Polycrisis : prompts for an emerging worldview

Taking the realms of business, finance and economic history by storm, polycrisis captures the complexity of an increasingly uncertain world in a state of flux and transition. Proponents of the polycrisis model, such as prominent economic historian and Financial Times contributing editor Adam Tooze, propose polycrisis as a marker of our age, capturing overlapping and interconnected crises beyond cause and effect. In his article, the authors offer some prompts for considering the usefulness and limitations of polycrisis for the anthropological toolkit. The authors cautiously welcome the polycrisis trope as a multidimensional means to account for the consequences of interrelated crises in an unprecedented era.Publisher PDFPeer reviewe

Personality traits and stress perception as predictors of students' online engagement during the COVID-19 pandemic

The COVID-19 pandemic coupled with increasing student numbers means online learning will remain a prevalent feature of the university experience, therefore it is vital that we understand how personality can influence student online engagement. The current study examined whether students' personality traits and stress perception predicted their online engagement with their studies during the COVID-19 pandemic. A sample of 301 first year psychology students completed the Big Five Inventory, Challenge and Hindrance Stress Scales, and the Online Student Engagement Scale, which measured students': engagement skills, emotional engagement, participation and performance. Results revealed that conscientiousness positively predicted all types of online engagement. Extraversion predicted participation and performance. Neuroticism predicted engagement skills, emotional engagement and performance, whilst agreeableness and openness to experience respectively predicted participation and emotional engagement. Additionally, stress perceived as a hindrance negatively predicted performance. These results reveal that students' personality traits and stress perception influence their online engagement and might enable educators to identify those who may require support in engaging with their studies

Hey ChatGPT, give me a title for a paper about degree apathy and student use of AI for assignment writing

ChatGPT could allow students to plagiarize the content of their coursework with little risk of detection. Little is known about undergraduate willingness to use AI tools. In this study, psychology undergraduates (N = 160) from the United Kingdom, indicated their willingness to use, and history of using, ChatGPT to write university assignments. Almost a third (32%) indicated that they would use such tools; 15% indicated that they had used them already. Neither personality (conscientiousness, agreeableness, Machiavellianism, narcissism), academic performance, nor study skills self-efficacy could predict future use of AI tools. A novel Degree Apathy Scale was the only significant predictor. Willingness to use AI tools was greater when the risk of getting caught was low, and punishment was light, particularly for those high in degree apathy. Findings suggest that degree apathy is a key risk factor in academic misconduct. Wider research and pedagogical applications of degree apathy are discussed