Elastic jump propagation across a blood vessel junction.

The theory of small-amplitude waves propagating across a blood vessel junction has been well established with linear analysis. In this study, we consider the propagation of large-amplitude, nonlinear waves (i.e. shocks and rarefactions) through a junction from a parent vessel into two (identical) daughter vessels using a combination of three approaches: numerical computations using a Godunov method with patching across the junction, analysis of a nonlinear Riemann problem in the neighbourhood of the junction and an analytical theory which extends the linear analysis to the following order in amplitude. A unified picture emerges: an abrupt (prescribed) increase in pressure at the inlet to the parent vessel generates a propagating shock wave along the parent vessel which interacts with the junction. For modest driving, this shock wave divides into propagating shock waves along the two daughter vessels and reflects a rarefaction wave back towards the inlet. However, for larger driving the reflected rarefaction wave becomes transcritical, generating an additional shock wave. Just beyond criticality this new shock wave has zero speed, pinned to the junction, but for further increases in driving this additional shock divides into two new propagating shock waves in the daughter vessels.

Effectiveness of self-help plus (SH+) in reducing anxiety and post-traumatic symptomatology among care home workers during the COVID-19 pandemic: a randomized controlled trial.

This article describes a randomized controlled trial to evaluate the effectiveness of a supervised online delivery of self-help plus (SH+), during the second wave of COVID-19 contagions in Northern Italy. The SH+ is a psychological intervention developed by the World Health Organization to increase a person's ability to deal with stress. In this trial, it was tested primarily as a tool to reduce anxiety and post-traumatic symptomatology in workers of residential nursing and care homes. In order to partial out non-specific effects of the intervention, the SH+ was compared to an equally supervised and structured alternative activity. Secondarily, in view of future emergencies, the potential of SH+ as a tool to reduce perceived stress, increase subjective well-being and foster individual resilience was explored. At post-intervention, the preregistered analysis revealed no difference in self-reported anxiety and/or post-traumatic symptomatology between the group receiving the SH+ and the group engaged in an alternative activity. Some specific and positive effects of the SH+ intervention were only found on self-reported intervention effectiveness and engagement in exploratory analyses. These findings raise the question whether the previously documented effectiveness of the SH+ on self-reported symptomatology and on the prevention of psychiatric conditions could be attributed mostly to non-specific rather than specific factors connected with participant enrolment in a psychological intervention. Indeed, the effects of the SH+ had been previously compared only to the effects of not being engaged in any alternative activity (often described in the literature as 'treatment as usual'-or 'enhanced treatment as usual', when some relevant information is given to the control group as a one-off). Given the negative findings of this study, before the SH+ is implemented in clinical practice, further studies should be conducted to examine its short- and long-term beneficial effects, by means of randomized studies that employ alternative but similarly structured interventions as control conditions, aiming to minimize the confounding effect of non-specific factors.

Prevalence of post-traumatic symptomatology and anxiety among residential nursing and care home workers following the first COVID-19 outbreak in Northern Italy.

The current COVID-19 pandemic has been officially linked to the deaths of hundreds of thousands of people across the globe in just a few months. It is particularly lethal for the elderly in general, as well as for populations residing in long-term stay facilities. By this time, those working and caring for high-risk populations have been exposed to very intense and sudden levels of physical and psychological strain. The situation has taken a particularly tragic turn in residential nursing and care homes (NCH), which were hit hard by the pandemic. In residential NCH, neither residents nor workers tend to have immediate access to the same expertise, medication and equipment as in hospitals, which exacerbates an already tense situation. Among the mental health conditions related to exposure to potentially traumatic events, post-traumatic stress disorder and anxiety are the most prevalent and scientifically recognized. In this survey-based epidemiological study, we test the prevalence of anxiety and post-traumatic symptomatology in residential nursing and care home workers-a group of individuals that has been largely neglected but who nonetheless plays a very important and sensitive role in our society. We do this by focusing on the North of Italy, the most affected region during the first COVID-19 outbreak in Italy. Using a single-stage cluster design, our study returns an estimate for the prevalence of moderate-to-severe anxiety and/or post-traumatic symptomatology of 43% (s.e. = 3.09; 95% CI [37-49]), with an 18% (s.e. = 1.83; 95% CI [14-22]) prevalence of comorbidity among workers of Northern Italian NCH between 15 June and 25 July 2020 (i.e. 12-52 days after the end of national lockdown). Women and workers who had recently been in contact with COVID-19-positive patients/colleagues are more likely to report moderate-to-severe symptoms, with odds ratios of 2.2 and 1.7, respectively.