Transitions between Inherent Structures in Water

The energy landscape approach has been useful to help understand the dynamic properties of supercooled liquids and the connection between these properties and thermodynamics. The analysis in numerical models of the inherent structure (IS) trajectories -- the set of local minima visited by the liquid -- offers the possibility of filtering out the vibrational component of the motion of the system on the potential energy surface and thereby resolving the slow structural component more efficiently. Here we report an analysis of an IS trajectory for a widely-studied water model, focusing on the changes in hydrogen bond connectivity that give rise to many IS separated by relatively small energy barriers. We find that while the system \emph{travels} through these IS, the structure of the bond network continuously modifies, exchanging linear bonds for bifurcated bonds and usually reversing the exchange to return to nearly the same initial configuration. For the 216 molecule system we investigate, the time scale of these transitions is as small as the simulation time scale ($\approx 1$ fs). Hence for water, the transitions between each of these IS is relatively small and eventual relaxation of the system occurs only by many of these transitions. We find that during IS changes, the molecules with the greatest displacements move in small ``clusters'' of 1-10 molecules with displacements of $\approx 0.02-0.2$ nm, not unlike simpler liquids. However, for water these clusters appear to be somewhat more branched than the linear ``string-like'' clusters formed in a supercooled Lennar d-Jones system found by Glotzer and her collaborators.Comment: accepted in PR

Calming the waters: initiatives for Asia Pacific maritime cooperation

This monograph includes the discussion papers presented at the First Meeting of the Council for Security Cooperation in the Asia Pacific (CSCAP) Maritime Cooperation Working Group held in Kuala Lumpur 2-3 June 1995. The establishment of a Working Group on Maritime Cooperation by CSCAP, as part of its initial work programme, is a reflection of the importance of the maritime environment in the security deliberations of Asia Pacific countries. The Asia Pacific region is distinctively maritime in nature. The sea, and issues to do with the sea, are an important part of international relations in the region, both between regional countries themselves, and between these countries and the rest of the world. The importance of maritime cooperation in the Asia Pacific region flows from the nature and complexity of the regional geographical environment, and the propensity for illegal activities and disputes to occur at sea. Maritime cooperation will contribute to regional stability by easing tension and reducing the risks of conflict while helping to promote a stable maritime regime in the region with the free and uninterrupted flow of seaborne trade, and nations able to pursue their maritime interests and manage their marine resources in an ecologically sustainable manner in accordance with agreed principles of international law. The CSCAP Maritime Co-operation Working Group has adopted a broad view of security, which encompasses a range of small 's' security issues, such as maritime safety, resources conservation, coastal zone management and unlawful activities at sea (such as drug smuggling, illegal population movements and piracy),as well as more conventional maritime security issues. A comprehensive approach to security was explicit in the Group's first meeting programme, which included sessions on shipping, marine science, and the marine environment. The papers in this volume provide a comprehensive review of the main maritime security concerns in the region

Regional maritime management and security

This monograph includes the discussion papers presented at the Third Meeting of the CSCAP Maritime Cooperation Working Group held in Bangkok 30 May-1 June 1997. It is the third in the series of similar monographs by the CSCAP Maritime Cooperation Working Group. The theme of the meeting was regional ocean management and security. Its objectives were fourfold: - to review progress with the Guidelines for Regional Maritime Cooperation; - to contribute to the development of new ideas about cooperative management of regional sea and ocean areas; - to identify present and planned activities in some area of regional maritime cooperation (such as shipping, resource management, pollution prevention, marine safety, and law and order at sea) which have benefits for regional security (that is, 'value added'); - and to share national and sub-regional perspectives of cooperative oceans and marine management. The overall aim of the meeting was to explore new ideas of preventive diplomacy and confidence building in the general area of regional maritime cooperation, particularly in the enclosed and semi-enclosed regional seas of Southeast and Northeast Asia, where maritime activity is increasing and cooperation so important. The opportunity was also taken to discuss existing arrangements for regional maritime cooperation and the experiences of other regions in the world with similar considerations of maritime cooperation (that is, the Baltic and Mediterranean seas, and the Caribbean)

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Fast Girls, Foreigners and GIs : An Exploration of the Discursive Strategies Through Which the Status of Pre-Marital (Hetero) sexual Ignorance and Restraint Was Upheld During the Second World War

This paper explores contradictions within qualitative data gathered among women and men whose young adulthood coincided with the Second World War. These data were generated as part of an ESRC-funded project which investigated the making of heterosexual relationships cross-generationally. They suggest the co-existence of both a prevalent taboo or stigma associated with sexual knowledge and practice before and outside marriage, and personal experiences of precisely these engagements with embodied sexuality. Drawing on Charles Tilly's work, the paper argues that, when interrogated, these contradictions can reveal the strategies through which a creaky heterosexual consensus was shored up during a period of military upheaval that profoundly destabilised existing beliefs and practices. Tilly differentiated between academic historians who sought to reconcile 'very large structural changes' and 'the changing experiences of ordinary people' through either collectivist or individualist approaches to 'history from below'. Neither of these methods could yield an adequate account, in his view. However, the 'lay historians' who participated in our study combined collectivist and individualist perspectives, thereby providing a unique insight into an era when collective values and individual practices were often in tension with one another. As our participants spoke about their young adulthood, their data revealed the potency of local gossip which mobilised wider discourses of alterity or 'othering', so shoring up a consensual view of sexual mores, despite the prevalence of attitudes and practices that contravened it. What we argue, therefore, is that rather than a half-remembered, contradictory account of heterosexuality during the 1920s and 1930s, the data we gathered in the early 21st century exemplifies precisely the discursive strategies of that period. In other words, these data shed light on the ways in which not only heterosexual norms, but also an entire, endangered system of distinctions based on class, gender and national identity was upheld.Peer reviewe