New approaches of source-sink metapopulations decoupling the roles of demography and dispersal

Source-sink systems are metapopulations of habitat patches with different, and possibly temporally varying, habitat qualities, which are commonly used in ecology to study the fate of spatially extended natural populations. We propose new techniques that allow to disentangle the respective contributions of demography and dispersal to the dynamics and fate of a single species in a source-sink metapopulation. Our approach is valid for a general class of stochastic, individual-based, stepping-stone models, with density-independent demography and dispersal, provided the metapopulation is finite or else enjoys some transitivity property. We provide 1) a simple criterion of persistence, by studying the motion of a single random disperser until it returns to its initial position; 2) a joint characterization of the long-term growth rate and of the asymptotic occupancy frequencies of the ancestral lineage of a random survivor, by using large deviations theory. Both techniques yield formulae decoupling demography and dispersal, and can be adapted to the case of periodic or random environments, where habitat qualities are autocorrelated in space and possibly in time. In this last case, we display examples of coupled time-averaged sinks allowing survival, as was previously known in the absence of demographic stochasticity for fully mixing (Jansen and Yoshimura, 1998) and even partially mixing (Evans et al., 2012; Schreiber, 2010) metapopulations.Comment: arXiv admin note: substantial text overlap with arXiv:1111.253

A history of concussions is associated with symptoms of common mental disorders in former male professional athletes across a range of sports

Objective: Recent reports suggest that exposure to repetitive concussions in sports is associated with an increased risk of symptoms of distress, anxiety and depression, sleep disturbance or substance abuse/dependence (typically referred as symptoms of common mental disorders[CMD]) and of later development of neurodegenerative disease, in particular chronic traumatic encephalopathy (CTE). The primary aim of this study was to explore the relationship between sports career-related concussions and the subsequent occurrence of symptoms of CMD among former male professional athletes retired from football (soccer), ice hockey and rugby (union). Methods: Cross-sectional analyses were performed on baseline electronic questionnaires from three prospective cohort studies among former male professional athletes retired from football (soccer), ice hockey and rugby (union). The number of confirmed concussions was examined through a single question, while symptoms of distress, anxiety and depression, sleep disturbance and adverse alcohol use were assessed using validated questionnaires. Results: From 1,957 former professional athletes contacted, a total of 576 (29%) completed the questionnaire. Of these, 23% had not incurred a concussion during their career, 34% had two or three, 18% four or five, and 11% six or more concussions. The number of sports career-related concussions was a predictor for all outcome measures (β = 0.072–0.109; P ≤ 0.040). Specifically, former professional athletes who reported a history of four or five concussions were approximately 1.5 times more likely to report symptoms of CMD, rising to a two- to five-fold increase in those reporting a history of six or more sports career-related concussions. Conclusions: These data demonstrate an association between exposure to sports concussion and subsequent risk of symptoms of CMD in former professional athletes across a range of contact sports. Further work to explore the association between sports concussion and symptoms of CMD is required; in the meanwhile, strategies for effective risk reduction and improved management appear indicated

Time taken to perform a rapid sequence intubation within a simulated prehospital environment

Abstract: Background. Rapid sequence intubation (RSI) involves inducing unconsciousness and paralysis in rapid succession in order to facilitate endotracheal tube placement. RSI has recently been introduced to the scope of practice of South African prehospital emergency care practitioners (ECPs). Despite this, there remains limited evidence supporting the efficacy and safety of RSI within this context. While in-hospital studies have shown that it can take 20 minutes or more to perform an RSI, little is known about the time taken to perform the procedure in the prehospital setting. Objective. To measure the time taken to perform an RSI in a simulated prehospital environment. Methods. A sample of final-year ECP students were video-recorded performing RSIs on a mannequin within a simulated prehospital environment. Data were gathered through an analysis of the recordings, allowing for the capturing of times taken to complete each of the phases of a RSI. Results. A mean time of 15 minutes 5 seconds was recorded to complete the procedure. This was shorter than times reported for in-hospital studies. Conclusion. RSI is a potentially harmful procedure if improperly performed and has the potential to create delays in transport that may not always be in the patient’s best interest. With a mean time of 15 minutes 5 seconds, the performance of RSI by ECP students in the simulated prehospital environment was faster than expected. Further research is recommended to explore the relationship between the performances observed in this mannequin-based study with those in authentic prehospital settings

Students’ views on the need for hostile environment awareness training for South African emergency medical care students

Background. South Africans experience high levels of contact crime, including assault, robbery and hijacking. Emergency medical services (EMS) are frequently called to the scene of such incidents. Their presence in these potentially hostile environments increases the risk of South African (SA) paramedics and paramedic students becoming victims of crime and violence. A 2015 study showed that ~66% of SA EMS staff reported being assaulted while on duty. During a 10-month period in 2016, Western Cape Province recorded >40 incidents of physical violence against their EMS personnel. Questions are being asked about how well prepared EMS staff are to operate in potentially hostile environments.Objectives. To explore emergency medical care (EMC) students’ experiences of violence and crime and their views on the need for hostile environment awareness training (HEAT) as part of their undergraduate degree programmes.Methods. A self-designed, non-validated, cross-sectional online survey questionnaire was used to document the experiences, views and opinions of 113 undergraduate EMC students from 4 SA universities. The questionnaire consisted of 24 closed-ended questions with pre-set Likert scale options focusing on documenting participants’ experiences, views and opinions regarding hostile environments and the need for HEAT.Results. A high percentage of participants (92%) indicated feeling unsafe while engaging in clinical learning shifts; 63% specified that they had personally witnessed violence against EMS crews, and 32% indicated that they had been assaulted while on duty. Unsurprisingly, 81% of the respondents felt that there is a need for inclusion of HEAT in the undergraduate curriculum.Conclusions. Participation in clinical learning shifts in the current SA prehospital EMS environment increases the risk of exposure to potentially hostile environments. Consequently, students feel unsafe and support the inclusion of HEAT as part of their undergraduate degree programmes

Doctors’, nurses’ and clinical associates’ understanding of emergency care practitioners

Background: Healthcare professionals’ understanding of the knowledge, skills and training of their counterparts from other disciplines cultivates appreciation and respect within the workplace. This, in turn, results in better teamwork and improved patient care. Emergency departments are places where emergency care practitioners (ECPs) engage with doctors, nurses and clinical associates. Whilst the importance of inter-professional communication and teamwork between in-hospital professionals and pre-hospital emergency care providers is acknowledged, no literature could be found describing exactly how much these in-hospital professionals understand about the training and capabilities of their ECP colleagues. Aim: The aim of this study was to assess the level of understanding that prospective doctors, nurses and clinical associates have regarding the training and capabilities of ECPs. Setting: The research was conducted in Johannesburg, South Africa, at two universities. Methods: Seventy-seven participants completed a purpose-designed questionnaire assessing their understanding regarding the education and clinical capabilities of ECPs. Results: In total, 64% of participants demonstrated a poor understanding of the level of education and clinical capabilities of ECPs. The remaining 36% showed only moderate levels of understanding. Conclusion: Medical, nursing and clinical associate graduates have a generally poor understanding of the education and clinical capabilities of their ECP colleagues who practise predominantly in the pre-hospital environment. This lack of understanding can become a barrier to effective communication between ECPs and in-hospital staff during patient handover in emergency departments. Contribution: This research highlights a lack of understanding about the role and function of South African ECPs as pre-hospital emergency care providers and the need for more effective inter-professional education

Réduction d'impôts et consommation des ménages en Belgique : une évaluation de l'impact de la réforme fiscale

Dans ce numéro de Regards économiques, nous examinons l’impact sur la consommation des ménages de la réforme fiscale introduite en Belgique à partir de 2002. Nos résultats indiquent un impact positif mais limité dans le temps.