From gyroscopic to thermal motion: a crossover in the dynamics of molecular superrotors

Localized heating of a gas by intense laser pulses leads to interesting acoustic, hydrodynamic and optical effects with numerous applications in science and technology, including controlled wave guiding and remote atmosphere sensing. Rotational excitation of molecules can serve as the energy source for raising the gas temperature. Here, we study the dynamics of energy transfer from the molecular rotation to heat. By optically imaging a cloud of molecular superrotors, created with an optical centrifuge, we experimentally identify two separate and qualitatively different stages of its evolution. The first non-equilibrium "gyroscopic" stage is characterized by the modified optical properties of the centrifuged gas - its refractive index and optical birefringence, owing to the ultrafast directional molecular rotation, which survives tens of collisions. The loss of rotational directionality is found to overlap with the release of rotational energy to heat, which triggers the second stage of thermal expansion. The crossover between anisotropic rotational and isotropic thermal regimes is in agreement with recent theoretical predictions and our hydrodynamic calculations

Fathers and work-life balance in France and the UK : policy and practice

Purpose – This paper focuses on the role of organizations in mediating the impact of national work-life balance (WLB) policy on employees, in particular fathers. Design/methodology/approach – It presents existing research about WLB policy implementation in organizations as well as the findings of empirical work in insurance and social work in France and the UK (questionnaire survey, case study analysis, interviews with national and sector-level trade union officials). Findings & Practical implications – These indicate that fathers’ take-up of WLB policies is the outcome of a complex dynamic between national fatherhood regimes, organizational and sector characteristics and the individual employee. They suggest that fathers tend to use WLB measures to spend time with their families where measures increase their sense of entitlement (state policies of paternity leave) or where measures offer non-gendered flexibility (reduced working time/organizational systems of flexi-time). In line with other studies it also finds that fathers extensively use informal flexibility where this is available (individual agency). These findings have implications for way WLB policies are framed at national and organizational level. Originality/value - Cross-national comparative research into WLB policy and practice at national and organizational level is very rare. The empirical work presented in this article, although exploratory, makes a significant contribution to our understanding of WLB policy and practice, particularly as it relates to fathers

Detecting abundance trends under uncertainty: the influence of budget, observation error and environmental change

ArticleCopyright © 2014 The Authors. Animal Conservation published by John Wiley & Sons Ltd on behalf of The Zoological Society of London.Population monitoring must robustly detect trends over time in a cost-effective manner. However, several underlying ecological changes driving population trends may interact differently with observation uncertainty to produce abundance trends that are more or less detectable for a given budget and over a given time period. Errors in detecting these trends include failing to detect declines when they exist (type II), detecting them when they do not exist (type I), detecting trends in one direction when they are actually in another direction (type III) and incorrectly estimating the shape of the trend. Robust monitoring should be able to avoid each of these error types. Using monitoring of two contrasting ungulate species and multiple scenarios of population change (poaching, climate change and road development) in the Serengeti ecosystem as a case study, we used a ‘virtual ecologist’ approach to investigate monitoring effectiveness under uncertainty. We explored how the prevalence of different types of error varies depending on budgetary, observational and environmental conditions. Higher observation error and conducting surveys less frequently increased the likelihood of not detecting trends and misclassifying the shape of the trend. As monitoring period and frequency increased, observation uncertainty was more important in explaining effectiveness. Types I and III errors had low prevalence for both ungulate species. Greater investment in monitoring considerably decreased the likelihood of failing to detect significant trends (type II errors). Our results suggest that it is important to understand the effects of monitoring conditions on perceived trends before making inferences about underlying processes. The impacts of specific threats on population abundance and structure feed through into monitoring effectiveness; hence, monitoring programmes must be designed with the underlying processes to be detected in mind. Here we provide an integrated modelling framework that can produce advice on robust monitoring strategies under uncertainty.Portuguese Foundation for Science and TechnologyEuropean Commissio