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Covid-19 has increased stress for psychiatric staff. This study reports the positive impact of brief videoconference-based Dialectical Behaviour Therapy skills training for acute psychiatric staff. It was delivered by clinical psychologists as a staff support response to Covid-19-related stress.

The southern rock lobster (SRL), Jasus edwardsii (Hutton, 1875) (Crustacea: Decapoda: Palinuridae), is one of Australia and New Zealand’s most valuable fishery resources. A large scale and prolonged reduction in the recruitment of SRL during years 2000 – 2010 translated into significant stock declines across the Australian fisheries. The geographical range of SRL spans more than 5000 km from Western Australia to New South Wales along the southern coast of Australia including Tasmania and around the entire New Zealand. Connectivity between distant populations is achieved solely through larval dispersal with adult movement being limited (Booth, 1997; Linnane et al., 2015). The SRL has a pelagic larval duration (PLD) of up to 24 months, one of the longest known in the marine environment and the longest among all rock lobsters (Booth, 1994; Bradbury and Snelgrove, 2001). SRL larvae can be carried hundreds of kilometres offshore and away from their origin, potentially connecting spawning grounds and recruitment sites hundreds of kilometres apart. This potential for widespread dispersal combined with unpredictable inter-annual and spatial variability of egg production and recruitment, make biophysical modelling an ideal approach to examine population connectivity for this species. This thesis assesses the population connectivity of SRL throughout its geographical distribution by the means of a larval dispersal model built utilising the best available hydrodynamic models and evidence based species-specific biological parameters. Prior to setting up the larval dispersal model, I performed a validation of two hydrodynamic models available in the study area, by comparing the model predicted time series of seawater temperature and ocean currents to in situ mooring measurements (Chapter 2). I found that the accuracy of the hydrodynamic models varied with the parameter investigated, the depth of the measurement and the geographical region. The model predictions of water temperature were more accurate than the predictions of ocean current velocities. This study identified important inaccuracies in the hydrodynamic models’ estimations of ocean parameters and on time scales relevant to larval dispersal studies. The largest errors in global ocean models are seen in coastal regions, where models have poor coverage due to their lower spatial resolution. Many global ocean models also do not explicitly resolve key hydrodynamic features in the coastal regions. I investigated the effect of nesting a highly-resolved coastal hydrodynamic model – ETAS – within the global BRAN model, on the passive dispersal of larvae released on the east coast of Tasmania (Chapter 3). I found significant differences in larval trajectories and dispersal metrics between the simulations using the nested ocean models and the simulations using only the global ocean model. Finally, an individual-based biophysical model was built for SRL larval dispersal (Chapter 4), the larval survival during dispersal and the probability of pueruli successfully settling in suitable habitat were estimated (Chapter 5). Larvae were released throughout the species geographic range during the egg hatching period over release dates spanning twenty years. In addition to dispersal metrics, I report the connectivity matrix between 16 fishery management zones across the dispersal domain. Dominated by the large west-flowing currents in the study region, the main larval transport was from west to east. The highest rates of survival to settlement were seen in larvae that metamorphosed early during the competency window or within few hundred of km from their release locations. South Australian and Victorian fisheries were important larval sources for most other fisheries east from them, while Victorian and Tasmanian fisheries received the largest proportion of successful pueruli from all other fisheries. The highest self-recruitment rates were observed in New Zealand, Northern South Australia and Tasmania 2 fisheries. This study offers valuable insight into the applications and limitations of hydrodynamic models in larval dispersal modelling and calls for the development of highly-resolved coastal ocean models. The SRL larval dispersal model developed in this work provides new information on this species’ potential for dispersal and the predicted population connectivity can be used to inform new fishery policies and help improve management of the SRL stock.

We consider the dynamical (time-dependent) Casimir-Polder force between an atom and a perfectly conducting wall, as well as the dynamical Casimir-Polder force between two atoms in the presence of a boundary condition such as a conducting wall. The dynamical Casimir-Polder forces are obtained from iterative solutions of the Heisenberg equations for the time evolution of the electric and magnetic field operators around one atom in the presence of the conducting wall and related field energy densities, which are valid for any initial state. We consider both the case of an initially bare atomic state and of an initially partially dressed atomic state. The problem of relativistic causality in the field propagation during the atomic self-dressing is also discussed. Finally, we consider a specific model for an atomic partially dressed state and discuss the possibility of experimental observation of the dynamical atom-wall Casimir-Polder force.

International audience

Evaluation of the value of the systolic pressure variations (SPV) under mechanical ventilation and of its components (delta down and delta up) in predicting fluid responsiveness in patients after coronary surgery by comparison with classic parameters. A prospective,randomized study, on 50 patients who underwent CABG surgery, in the early postoperative period (the first two hours). We assessed the following parameters: CO, CI, CVP, PCWP, SAP, DAP, MAP, SVP, delta down and delta up. The including criteria were: sinus rhythm, CIor = 2,5 l/min/m2, PCP18 mmHg. All the patients underwent a fluid challenge (500 ml of colloids in 10 min). Three patients were excluded: 3 for a PCWP18 mm Hg, 1 for loosing the sinus rhythm and 1 for an early return in the OR for bleeding. After a new assessment of the same parameters the patients were divided in two groups: group A (28 pts) with a raise of CI15%, and group B (22 pts) with a CI variation15%. In each group was statistically analyzed the variation of each parameter. Results Both parameters provided by SPV analysis are able to predict the fluid responsiveness with a great accuracy: the positive predictive value of a SPV12 mmHg is above 92,85% and of a delta down5 mm Hg is above 96,42%; the negative predictive value of a SPVor = 12 mmHg is above 90,90% and of a delta down = 5 mm Hg is above 95,45%. None of the "classic" pressure parameters (MAP, CVP, PCWP) used in hemodynamic assessment have revealed a statistical significant variation. The SVP method's parameters are superior to classic pressure parameters (MAP, CVP, PCWP) in predicting fluid responsiveness in patients after coronary surgery.

We consider the dynamical atom-surface Casimir-Polder force in the non-equilibrium configuration of an atom near a perfectly conducting wall, initially prepared in an excited state with the field in its vacuum state. We evaluate the time-dependent Casimir-Polder force on the atom, and find that it shows an oscillatory behavior from attractive to repulsive both in time and in space. We also investigate the asymptotic behavior in time of the dynamical force and of related local field quantities, showing that the static value of the force, as obtained by a time-independent approach, is recovered for times much larger than the timescale of the atomic self-dressing, but smaller than the atomic decay time. We then discuss the evolution of global quantities such as atomic and field energies, and their asymptotic behavior. We also compare our results for the dynamical force on the excited atom with analogous results recently obtained for an initially bare ground-state atom. We show that new relevant features are obtained in the case of an initially excited atom, for example much larger values of the dynamical force with respect to the static one, allowing for an easier way to single-out and observe the dynamical Casimir-Polder effect., Comment: 9 pages, 5 figures

In this paper we review different aspects of the dynamical Casimir¿Polder potential between a neutral atom and a perfectly conducting plate under nonequilibrium conditions. In order to calculate the time evolution of the atom¿wall Casimir¿Polder potential, we solve the Heisenberg equations describing the dynamics of the coupled system using an iterative technique. Different nonequilibrium initial states are considered, such as bare and partially dressed states. The partially dressed states considered are obtained by a sudden change of a physical parameter of the atom or of its position relative to the conducting plate. Experimental feasibility of detecting the considered dynamical effects is also discussed., The authors gratefully acknowledge financial support by the Julian Schwinger Foundation, by Ministero dell’Istruzione, dell’Università e della Ricerca and by Comitato Regionale di Ricerche Nucleari e di Struttura della Materia.