Kinetics of Ordering in Fluctuation-Driven First-Order Transitions: Simulations and Dynamical Renormalization

Many systems where interactions compete with each other or with constraints are well described by a model first introduced by Brazovskii. Such systems include block copolymers, alloys with modulated phases, Rayleigh-Benard Cells and type-I superconductors. The hallmark of this model is that the fluctuation spectrum is isotropic and has a minimum at a nonzero wave vector represented by the surface of a d-dimensional hyper-sphere. It was shown by Brazovskii that the fluctuations change the free energy structure from a $\phi ^{4}$ to a $\phi ^{6}$ form with the disordered state metastable for all quench depths. The transition from the disordered to the periodic, lamellar structure changes from second order to first order and suggests that the dynamics is governed by nucleation. Using numerical simulations we have confirmed that the equilibrium free energy function is indeed of a $\phi ^{6}$ form. A study of the dynamics, however, shows that, following a deep quench, the dynamics is described by unstable growth rather than nucleation. A dynamical calculation, based on a generalization of the Brazovskii calculations shows that the disordered state can remain unstable for a long time following the quench.Comment: 18 pages, 15 figures submitted to PR

Origin of Life

The evolution of life has been a big enigma despite rapid advancements in the fields of biochemistry, astrobiology, and astrophysics in recent years. The answer to this puzzle has been as mind-boggling as the riddle relating to evolution of Universe itself. Despite the fact that panspermia has gained considerable support as a viable explanation for origin of life on the Earth and elsewhere in the Universe, the issue remains far from a tangible solution. This paper examines the various prevailing hypotheses regarding origin of life like abiogenesis, RNA World, Iron-sulphur World, and panspermia; and concludes that delivery of life-bearing organic molecules by the comets in the early epoch of the Earth alone possibly was not responsible for kick-starting the process of evolution of life on our planet.Comment: 32 pages, 8 figures,invited review article, minor additio

Exploring the nature of resilience in paramedic practice: A psycho-social study

Previous research has identified that paramedics experience high levels of stress and sickness rates which have escalated in recent years due to changes to workforce restructuring. While a number of studies have investigated resilience among healthcare professionals, there is little research exploring how paramedics address work challenges and how they become resilient. Using psychosocial methodology, seven paramedics participated in Free Association Narrative interviewing; all were based at one regional centre. In line with the study design, data analysis adopted a psycho-social approach that generated four themes and 10 sub-themes which, characterised participants’ experiences. Coping and resilience was impacted upon via formal methods of support including management, debriefing and referral to outside agencies. Alongside this, more informal methods aided resilience. Informal methods included peer support, support from family and friends and the use of humour. Uniquely, this study uncovered how detachment is used to manage emotions. The study has implications for the services need to support the emotional needs of paramedics