Modeling the interactions between river morphodynamics and riparian vegetation

The study of river-riparian vegetation interactions is an important and intriguing research field in geophysics. Vegetation is an active element of the ecological dynamics of a floodplain which interacts with the fluvial processes and affects the flow field, sediment transport, and the morphology of the river. In turn, the river provides water, sediments, nutrients, and seeds to the nearby riparian vegetation, depending on the hydrological, hydraulic, and geomorphological characteristic of the stream. In the past, the study of this complex theme was approached in two different ways. On the one hand, the subject was faced from a mainly qualitative point of view by ecologists and biogeographers. Riparian vegetation dynamics and its spatial patterns have been described and demonstrated in detail, and the key role of several fluvial processes has been shown, but no mathematical models have been proposed. On the other hand, the quantitative approach to fluvial processes, which is typical of engineers, has led to the development of several morphodynamic models. However, the biological aspect has usually been neglected, and vegetation has only been considered as a static element. In recent years, different scientific communities (ranging from ecologists to biogeographers and from geomorphologists to hydrologists and fluvial engineers) have begun to collaborate and have proposed both semiquantitative and quantitative models of river-vegetation interconnections. These models demonstrate the importance of linking fluvial morphodynamics and riparian vegetation dynamics to understand the key processes that regulate a riparian environment in order to foresee the impact of anthropogenic actions and to carefully manage and rehabilitate riparian areas. In the first part of this work, we review the main interactions between rivers and riparian vegetation, and their possible modeling. In the second part, we discuss the semiquantitative and quantitative models which have been proposed to date, considering both multi- and single-thread river

Palaeo-dust records: a window to understanding past environments

Dust entrainment, transport over vast distances and subsequent deposition is a fundamental part of the Earth system. Yet the role and importance of dust has been underappreciated, due largely to challenges associated with recognising dust in the landscape and interpreting its depositional history. Despite these challenges, interest in dust is growing. Technical advances in remote sensing and modelling have improved understanding of dust sources and production, while advances in sedimentology, mineralogy and geochemistry (in particular) have allowed dust to be more easily distinguished within sedimentary deposits. This has facilitated the reconstruction of records of dust emissions through time. A key advance in our understanding of dust has occurred following the development of methods to geochemically provenance (fingerprint) dust to its source region. This ability has provided new information on dust transport pathways, as well as the reach and impact of dust. It has also expanded our understanding of the processes driving dust emissions over decadal to millennial timescales through linking dust deposits directly to source area conditions. Dust provenance studies have shown that dust emission, transport and deposition are highly sensitive to variability in climate. They also imply that dust emissions are not simply a function of the degree of aridity in source areas, but respond to a more complex array of conditions, including sediment availability. As well as recording natural variability, dust records are also shown to sensitively track the impact of human activity. This is reflected by both changing dust emission rates and changing dust chemistry. Specific examples of how dust responds to, and records change, are provided with our work on dust emissions from Australia, the most arid inhabited continent and the largest dust source in the Southern Hemisphere. These case studies show that Australian dust emissions reflect hydro-climate variability, with reorganisation of Australian dust source areas occurring during the mid to late Holocene. Dust emissions are shown to sensitively map the structure of the Last Glacial Maximum in Australia, demonstrating that this period was associated with enhanced, but also variable dust emissions, driven by changing sources area conditions. Finally we show how dust emissions have responded to the arrival of Europeans and the associated onset of broad-scale agriculture across the Australian continent

Protocol for a systematic review to identify the barriers and facilitators to deliver bystander cardiopulmonary resuscitation (CPR) in disadvantaged communities

Background A key determinant of survival after out-of-hospital cardiac arrest (OHCA) is bystander cardio pulmonary resuscitation (CPR) which can more than double an individual’s chances of surviving to discharge from hospital. The experience of other international OHCA survival programmes has shown that increasing bystander CPR is strongly associated with an increase in overall survival. However, existing data suggest that the more economically deprived an area is the higher the incidence of cardiac arrest. At the same time, rates of bystander CPR in the same areas are lower, which could result in lower survival rates. High-profile awareness raising campaigns that are generic focus have not specifically targeted people living in deprived communities who may require more tailored campaigns and interventions to change attitudes and improve confidence to administer bystander CPR. Therefore, this systematic review will explore the facilitators and barriers to engaging with bystander CPR which exist in deprived communities The secondary objective is to identify existing bystander OHCA social marketing and social network intervention campaigns that could inform future activities to improve the rate of bystander CPR in deprived communities. Methods Systematic review searching the following databases: CINAHL, MEDLINE, PsycINFO, and Web of Science Core Collection Citation Indexes. Unpublished ‘grey’ literature will also be sourced through web searches, stakeholder interviews, and an advisory group. The reference lists of any relevant reviews will also be checked for additional studies. References will be restricted to those published in 2000 onwards. Authors will independently screen, assess data quality, and extract data for synthesis. A narrative synthesis of study findings will be conducted, with findings presented thematically. Discussion This review will focus on all studies that seek to examine the barriers and facilitators to the delivery of bystander CPR in deprived communities and identify examples of previous interventions or activities that could inform the design of a future theory-based intervention to improve the rate of bystander CPR in deprived communities

Traumatic cardiac arrest in Sweden 1990-2016 - a population-based national cohort study.

BACKGROUND: Trauma is a main cause of death among young adults worldwide. Patients experiencing a traumatic cardiac arrest (TCA) certainly have a poor prognosis but population-based studies are sparse. Primarily to describe characteristics and 30-day survival following a TCA as compared with a medical out-of-hospital cardiac arrest (medical CA). METHODS: A cohort study based on data from the nationwide, prospective population-based Swedish Registry for Cardiopulmonary Resuscitation (SRCR), a medical cardiac arrest registry, between 1990 and 2016. The definition of a TCA in the SRCR is a patient who is unresponsive with apnoea where cardiopulmonary resuscitation and/or defibrillation have been initiated and in whom the Emergency Medical Services (EMS, mainly a nurse-based system) reported trauma as the aetiology. Outcome was overall 30-day survival. Descriptive statistics as well as multivariable logistic regression models were used. RESULTS: In all, between 1990 and 2016, 1774 (2.4%) cases had a TCA and 72,547 had a medical CA. Overall 30-day survival gradually increased over the years, and was 3.7% for TCAs compared to 8.2% following a medical CA (p < 0.01). Among TCAs, factors associated with a higher 30-day survival were bystander witnessed and having a shockable initial rhythm (adjusted OR 2.67, 95% C.I. 1.15-6.22 and OR 8.94 95% C.I. 4.27-18.69, respectively). DISCUSSION: Association in registry-based studies do not imply causality but TCA had short time intervals in the chain of survival as well as high rates of bystander-CPR. CONCLUSION: In a medical CA registry like ours, prevalence of TCAs is low and survival is poor. Registries like ours might not capture the true incidence. However, many individuals do survive and resuscitation in TCAs should not be seen futile

Validity of reported data in the Swedish Cardiac Arrest Register in selected parts in Sweden

Aim: To describe differences and similarities between reported and non-reported data in the Swedish Cardiac Arrest Register in selected parts in Sweden. Methods: Prospective and retrospective data for treated OHCA patients in Sweden, 2008-2010, were compared in the Swedish Cardiac Arrest Register. Data were investigated in three Swedish counties, which represented one third of the population. The recording models varied. Prospective data are those reported by the emergency medical service (EMS) crews, while retrospective data are those missed by the EMS crews but discovered afterwards by cross-checking with the local ambulance register. Result: In 2008-2010, the number of prospectively (n = 2398) and retrospectively (n = 800) reported OHCA cases was n = 3198, which indicates a 25% missing rate. When comparing the two groups, the mean age was higher in patients who were reported retrospectively (69 years vs. 67 years; p = 0.003). There was no difference between groups with regard to gender, time of day and year of OHCA, witnessed status or initial rhythm. Bystander cardiopulmonary resuscitation (CPR) was more frequent among patients who were reported prospectively (65% vs. 60%; p = 0.023), whereas survival to one month was higher among patients who were reported retrospectively (9.2% vs. 11.9%; p = 0.035). Conclusion: Among 3198 cases of OHCA in three counties in Sweden, 800 (25%) were not reported prospectively by the EMS crews but were discovered retrospectively as missing cases. Patients who were reported retrospectively differed from prospectively reported cases by being older, having less frequently received bystander CPR but having a higher survival rate. Our data suggest that reports on OHCA from national quality registers which are based on prospectively recorded data may be influenced by selection bias. (C) 2013 Elsevier Ireland Ltd. All rights reserved

Better outcome of exercise-related out-of-hospital cardiac arrest in men and in the young

Abstract Background Survival from out-of-hospital cardiac arrest (OHCA) is higher if the arrest occurs in relation to physical activity,however there is contradicting data on prognosis with regards to gender and age. The purpose of the study was to compare prognosis and circumstances of exercise-related OHCA in different age-groups as well as between genders in a large unselected population. Methods Observational data from exercise-related OHCA occurring outside of home reported to the Swedish Register of Cardiopulmonary Resuscitation (SRCR) from 2011 to 2014 and from 2016 to 2018 was analyzed. Comparing analyses were made for three different age-groups (0–35, 36–65 and &amp;gt;65 years) and for males versus females. Results A total number of 9607 cases of OHCA outside of home where resuscitation was attempted occurred during the study period, 635 (6.6%) were exercise-related. Mean age was similar between males and females (59.1 years in both groups). The 30-day survival rate was significantly higher among exercise-related OHCAs compared to non-exercise-related OHCAs (44.5% vs 18.8%, p&amp;lt;0.0001). The highest survival rate was observed in the age-group 0–35 years, compared to 36–65 years and &amp;gt;65 years respectively (59.6% vs 46.0% and 40.4% respectively, p=0.01). A sub-group analysis of victims aged 0–25 years (n=32) showed a survival rate of 68.8%. Exercise-related OHCA in women (9.1% of total) were bystander witnessed to a lower extent than in men (66.7% vs 79.6%, p=0.03). Both men and women received bystander CPR at the same extent but median time to CPR was 1min longer for women (2.0 vs 1.0 min, p=0.001). Women had lower rates of ventricular fibrillation as initial rhythm (43.4% vs 64.7%, p=0.003) and 30-day survival was lower among women (29.3% vs 46.0%, p=0.02). Conclusion Women seem to be protected from exercise-related OHCA but in case of occurrence the prognosis is actually worse compared to men. This may partly be explained by lower grade of bystander witnesses and longer time to CPR, but the results indicate the need for further studies on additional factors, such as variances in underlying disease pattern and exercise habits of women. In addition, this study presents an exceptionally high survival rate for exercise-related OHCA in the youngest age-groups, especially in victims 0–25 years of age which is a novel finding. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): The Swedish Heart-Lung Foundation, Laerdal Foundation </jats:sec

Higher survival rates in exercise-related out-of-hospital cardiac arrests, compared to non-exercise-related – a study from the Swedish Register of Cardiopulmonary Resuscitation

Background: Despite the positive effects of physical activity, the risk of sudden cardiac arrest is transiently increased during and immediately after exercise. The purpose of this study was to assess the incidence of exercise-related out-of-hospital cardiac arrest in the general population and to compare characteristics and prognosis of these cardiac arrests with non-exercise-related out-of-hospital cardiac arrests.Methods: Data from all cases of treated out-of-hospital cardiac arrest outside of home reported to the Swedish Register of Cardiopulmonary Resuscitation from 2011-2015 in three counties of Sweden were investigated (population 2.1 m). This registry captures almost 100% of all out-of-hospital cardiac arrests in Sweden. Results Of 1825 out-of hospital cardiac arrests, 137 (7.5%) were exercise-related, resulting in an incidence of 1.2 per 100,000 person-years. The 30-day survival rate was significantly higher among exercise-related out-of hospital cardiac arrests compared to non-exercise-related out-of-hospital cardiac arrests (54.3 % vs 19.4%, p &lt; 0.0001). Patients suffering an exercise-related out-of-hospital cardiac arrest were on average 10 years younger than those who had a non-exercise-related out-of-hospital cardiac arrest, 56.4 years compared to 67.2 years. Exercise-related out-of-hospital cardiac arrests were more often witnessed (89.4% vs 78.6%, p = 0.002), had higher rates of bystander cardiopulmonary resuscitation (80.3% vs 61.0%, p &lt; 0.0001) and were more frequently connected to an automated external defibrillator (20.4% vs 4.6%, p &lt; 0.0001).Conclusions: Cardiac arrests that occur in relation to exercise have a significantly better prognosis and outcome than non-exercise-related cardiac arrests. This may be explained by favourable circumstances but may also reflect that these persons experience a sudden cardiac arrest at a lower degree of coronary artery disease, due to their younger age and to exercise being a trigger.</p

Attribution of sources to metal accumulation in an alpine tarn, the Snowy Mountains, Australia

This study analyses 1800 years of heavy metal accumulation in a remote alpine lake experiencing long-range atmospheric contamination and additional inputs of Ag from cloud seeding. In comparison to previous work undertaken on peats, lake sediments show limited post-industrial metal enrichment with enrichment factors of Ag: 1.3, Pb: 1.3, Zn: 1.1, Cu: 1.2 compared to Ag: 2.2, Pb: 3.3, Zn: 2.1, Cu: 4.1 for peat. We show this to be the result of substantial fluvial lithogenic flux of metals (92-97% of total metal flux) to the lake. Total annual metal flux to the lake ranges from: Ag: 4-12 ng/cm2/yr to Zn: 3 383-11 313 ng/cm2/yr. As a result, any contribution of cloud seeding to additional enrichment of Ag in lake sediments is considered negligible. Results show that metal enrichment is not necessarily ubiquitous through a landscape. This has implications for predicting the impacts of atmospheric metal pollution to complex environmental systems