Barosensory vessel mechanics and the vascular sympathetic baroreflex: Impact on blood pressure homeostasis

Abstract An age‐associated increase in arterial blood pressure is evident for apparently healthy humans. This is frequently attributed to stiffening of the central arteries and a concurrent increase in sympathetic outflow, potentially mediated by a reduced ability of the baroreceptive vessels to distend. This is supported, in part, by a reduced mechanical component of the vascular sympathetic baroreflex (i.e., a reduction in distension for a given pressure). Previous characterization of the mechanical component has assessed only carotid artery distension; however, evidence suggests that both the aortic and carotid baroreflexes are integral to blood pressure regulation. In addition, given that baroreceptors are located in the vessel wall, the change in wall tension, comprising diameter, pressure and vessel wall thickness, and the mechanics of this change might provide a better index of the baroreceptor stimulus than the previous method used to characterize the mechanical component that relies on diameter alone. This brief review summarizes the data using this new method of assessing barosensory vessel mechanics and their influence on the vascular sympathetic baroreflex across the lifespan

Marche et environnements urbains contrastés. Perspectives internationales et interdisciplinaires

International audienceEn moins de trente ans, les moyens de transport, les services à la mobilité et les manières de se déplacer n’ont cessé de se développer et de se diversifier, pérennisant l’image de la ville comme « espace des flux », modelant les paysages urbains, favorisant une injonction à « être mobile ». Dans ce contexte, la marche fait l’objet d’une attention renouvelée. Une approche ouverte au croisement de la géographie, de la santé publique, de la psychologie et de l’urbanisme s’impose. Si une telle approche permet l’ouverture à d’autres perspectives et la production de connaissances nouvelles issues de cette interdisciplinarité, ces connaissances peuvent également nous conduire à des interventions urbaines et architecturales appropriées, ciblées et sensibles. Ce sont autant de questions que nous désirons développer dans le cadre de ce numéro thématique interdisciplinaire sur le marcheur et son environnement. Trois axes sont proposés où, dans un premier temps, nous nous intéressons aux figures du marcheur d’aujourd’hui, dans une seconde partie, aux conditions de possibilités de la marche et, dans une troisième partie, aux manières d’évaluer la marche selon le point de vue du marcheur

Project bank accounts: the second wave of security of payment?

Project bank accounts: the second wave of security of payment

EFFECTS OF VARIABLE FIRE SEVERITY ON FORAGE PRODUCTION AND FORAGING BEHAVIOR OF MOOSE IN WINTER

The increasing frequency and extent of wildfires in Alaska over the last half century has spurred increased interest in understanding the role of post-fire succession on vegetation establishment. Our primary goal was to examine how wildfire affects production and distribution of winter forage for moose  (Alces alces) in interior Alaska, and how these changes in forage availability control forage offtake. Fire severity classification was based on post-fire depth of residual soil organic matter. We used a browse survey protocol to estimate the biomass of current year production (kg/ha) and overwinter offtake (kg/ha) by moose. Under the assumption of homogenous effects of fire severity on regeneration, we estimated that moose consumed 36% of all forage (current annual growth) across the study area. However, we found that moose exhibited significantly higher browse consumption relative to browse production in high fire severity sites than in low severity sites (P < 0.05). When we adjusted our estimates of forage production and consumption by accounting for the significant differences in browse consumption between severity classes and their distribution across the burn, moose consumed approximately 49% of available forage. Assessments of fire severity and its spatial distribution through remote sensing techniques and on-the-ground sampling provides improved projections of vegetation regeneration pathways following wildfires, and thus refined estimates of future browse production and habitat quality for moose

EFFECTS OF VARIABLE FIRE SEVERITY ON FORAGE PRODUCTION AND FORAGING BEHAVIOR OF MOOSE IN WINTER

The increasing frequency and extent of wildfires in Alaska over the last half century has spurred increased interest in understanding the role of post-fire succession on vegetation establishment. Our primary goal was to examine how wildfire affects production and distribution of winter forage for moose  (Alces alces) in interior Alaska, and how these changes in forage availability control forage offtake. Fire severity classification was based on post-fire depth of residual soil organic matter. We used a browse survey protocol to estimate the biomass of current year production (kg/ha) and overwinter offtake (kg/ha) by moose. Under the assumption of homogenous effects of fire severity on regeneration, we estimated that moose consumed 36% of all forage (current annual growth) across the study area. However, we found that moose exhibited significantly higher browse consumption relative to browse production in high fire severity sites than in low severity sites (P < 0.05). When we adjusted our estimates of forage production and consumption by accounting for the significant differences in browse consumption between severity classes and their distribution across the burn, moose consumed approximately 49% of available forage. Assessments of fire severity and its spatial distribution through remote sensing techniques and on-the-ground sampling provides improved projections of vegetation regeneration pathways following wildfires, and thus refined estimates of future browse production and habitat quality for moose

Chronic pain in the paramedic practice setting – a qualitative study of patients’ perspective

Background: Chronic pain is highly prevalent among the global population and has a significant impact on a patient's livelihood in multiple areas. Chronic pain is now more widely recognised as a standalone medical condition by most healthcare disciplines, separate from that of acute pain. This has allowed for the development of a unique evidence-based approach to caring for these patients, which incorporates the biological, psychological, and social dimensions in which chronic pain transverses. However, in the paramedic practice setting, chronic pain has received scant mention. This knowledge gap leaves many paramedics operating without guidelines suitable for the care of chronic pain patients or an epidemiological foundation describing the incidence or treatment requirements of this patient cohort. Most importantly, the perspectives and experiences of chronic pain patients who are treated by paramedics have yet to be investigated which is vital to ensure relevant care. Aims: To describe and understand the experience of patients requiring ambulance attendance for chronic pain-related complaints. Methods: Six participants were enlisted using convenience sampling. Participants responded, via Zoom, to an inductive, semi-structured interview. Analysis was performed using qualitative reflexive thematic analysis with a non-positivist, constructive approach. Results: The themes identified were ‘the impact of stigma’ and ‘inadequate paramedic education’. Most participants shared similar attitudes and experiences regarding paramedic management, expressing dissatisfaction with the current standard of practice in relation to chronic pain complaints. Conclusion: Patients experiencing chronic pain are underserved by the standard of care being offered in this practice setting. Concerns raised by patients centred around the impact both stigma and educational understanding have on treatment. These findings indicate a need for further research, including the revision of guidelines and consideration of the patient perspective to be conducted in this area

‘Why has my world become more confusing than it used to be?’ Professional doctoral students reflect on the development of their identity

This article reports on research into the experience of professional doctoral students and is written by the students themselves. We, the authors, are currently studying for the Doctorate in Education at the University of Manchester, UK. We place our work in the context of recent empirical research into the development of doctoral student identity, noting that these literatures are usually authored by programme directors and supervisors. Using a theoretical approach based on the work of Etienne Wenger, we examine how the aims and curriculum of our programme interplay with our professional learning. In interviews with our cohort of students, we explore the complexity and non-linearity of learning. We do not find a simple progression from practitioner to researcher; rather, we find a fluid and complex relationship between those two identities. We consider the extent to which Wenger’s modes of identification are a useful conceptual tool for understanding this interplay and for theorising about our findings. We conclude that there is further scope for the development of our theoretical framework by drawing on other scholarly work on identity development and reflexivit

Prevalence of subclinical cardiac abnormalities in patients with metal-on-metal hip replacements

Background Metal-on-metal (MOM) hip prostheses have a higher failure rate than conventional prostheses and leaching of cobalt and chromium has been linked to cardiomyopathy. We screened MOM subjects to evaluate if cobalt and chromium are related to subclinical cardiac dysfunction. Methods A single centre, non-randomised, observational study using echocardiography in 95 patients who had undergone MOM hip prostheses, and 15 age matched controls with non-MOM hip replacement. Serial plasma cobalt and chromium levels were recorded, and data compared by tertiles of cobalt exposure. Results Indexed left ventricular (LV) end-diastolic and end-systolic volumes (EDVi and ESVi) increased with tertile of cobalt (omnibus p = 0.003 for EDVi and ESVi), as did indexed left atrial (LA) volumes (p = 0.003). MOM subjects had 25% larger EDVi than controls, 32% larger ESVi (40 ml vs. 32 ml, and 15 ml vs. 11 ml, p = 0.003 for both) and 28% larger indexed LA (23 ml vs. 18 ml, p = 0.002). There were no differences in LV systolic or diastolic function, including ejection fraction, tissue velocity and mitral E/e′. Estimated glomerular filtration rate was 18% lower in the highest tertile compared with the lowest (p = 0.01) and correlated inversely with LA volume (r = −0.36, p < 0.001) and LV EDV (r = −0.24, p = 0.02). Conclusions No correlations between sensitive measures of systolic or diastolic cardiac function or serum cobalt/chromium levels were observed in this study. However, there was a relationship between increasing left ventricular and left atrial volumes and declining renal function with high cobalt levels which requires further evaluation in MOM patients

Contextualising Safety in Numbers: a longitudinal investigation into change in cycling safety in Britain, 1991–2001 and 2001–2011

Introduction The ’Safety in Numbers’ (SiN) phenomenon refers to a decline of injury risk per time or distance exposed as use of a mode increases. It has been demonstrated for cycling using cross-sectional data, but little evidence exists as to whether the effect applies longitudinally —that is, whether changes in cycling levels correlate with changes in per-cyclist injury risks. Methods This paper examines cross-sectional and longitudinal SiN effects in 202 local authorities in Britain, using commuting data from 1991, 2001 and 2011 censuses plus police -recorded data on ’killed and seriously injured’ (KSI) road traffic injuries. We modelled a log-linear relationship between number of injuries and number of cycle commuters. Second, we conducted longitudinal analysis to examine whether local authorities where commuter cycling increased became safer (and vice versa). Results The paper finds a cross-sectional SiN effect exists in the 1991, 2001 and 2011 censuses. The longitudinal analysis also found a SiN effect, that is, places where cycling increased were more likely to become safer than places where it had declined. Finally, these longitudinal results are placed in the context of changes in pedestrian, cyclist and motorist safety. While between 1991 and 2001 all modes saw declines in KSI risk (37% for pedestrians, 36% for cyclists and 27% for motor vehicle users), between 2001 and 2011 pedestrians and motorists saw even more substantial declines (41% and 49%), while risk for cyclists increased by 4%. Conclusion The SiN mechanism does seem to operate longitudinally as well as cross-sectionally. However, at a national level between 2001-11 it co-existed with an increase in cyclist injury risk both in absolute terms and in relation to other modes