The water masses off the west coast of North America

In reporting the results of the 1937 cruises of the Bluefin off southern California, Sverdrup and Fleming (in press) found that within the limited area which they investigated, two primary water masses were present, mixtures of which made up the water at depths between 200 meters and 400 meters in this region, and they developed a convenient method of using temperature-salinity relationships to study the processes of mixing...

Inferring Environmental Change in Estuaries from Plant Macrofossils

Aquatic plants are critical components of estuarine ecosystems supporting biodiversity and a range of ecosystem services such as sediment stabilisation and denitrification. However, estuarine plants, similar to their freshwater counterparts, are in decline and under threat. The examination of remains of aquatic plants in sediment records can document the fate of the plants themselves, along with numerous natural and anthropogenic changes in estuaries, including those associated with relative sea level change, pollution and habitat degradation. In comparison with other proxies, the use of macrofossils in estuaries is in its relative infancy. However, many approaches to the examination of plant macrofossils can be utilised from the freshwater domain where a number of advances have been made, particularly in the past decade

Parent and staff experiences of a feasibility trial evaluating neurally adjusted ventilatory assist in infants with acute viral bronchiolitis: A qualitative study.

There is limited literature regarding family and staff experiences of participating in clinical trials. A qualitative study was embedded in the NAVABronch feasibility trial evaluating the effectiveness of a novel mode of ventilation, neurally adjusted ventilatory assist (NAVA), in infants with acute viral bronchiolitis. The aim of this qualitative study was to explore the experiences of parents and health care practitioners (HCPs) involved in the NAVABronch Trial. Semi-structured interviews were conducted with two parents and two focus groups were held with six HCPs. Four themes were identified from the focus groups: (1) Creating staff engagement, (2) Education to deliver NAVA, (3) Normalizing NAVA in clinical practice (4) Creating meaningful study outcomes and (5) support of parents during the trial, this theme was generated from the parent interviews. The findings indicated the need for education regarding NAVA for HCPs which would lead to increased confidence, better guidance around the use of NAVA and the need for NAVA to be normalized and embedded into the unit culture. Parents identified the need for further support around preparation for what may happen as a result of the interventions, particularly the weaning of sedation. Our study indicates that staff and parents had no concerns regarding the trial methods and procedures. Conducting clinical trials in Paediatric Intensive Care Units (PICUs) is challenging and complex. There is limited literature regarding family and staff experiences of participating in clinical trials. Understanding their experiences is crucial in ensuring trial success. [Abstract copyright: © 2024 The Authors. Nursing in Critical Care published by John Wiley & Sons Ltd on behalf of British Association of Critical Care Nurses.

Mid-infrared spectroscopy as a potential tool for reconstructing lake salinity

Many aquatic ecosystems in Australia are impacted or threatened by salinisation; however, there is a paucity of records detailing the changes in salinity of individual water bodies that extend beyond a few decades. One way to overcome this issue is the use of inference models, which have typically been based on biological proxies. This pilot project investigates the potential for mid-infrared spectroscopy (MIRS) to provide an alternative method of reconstructing past salinity levels in Australian lakes. A small (19 lakes) calibration dataset was used to develop a MIRS-based lake water salinity inference model (measured vs. inferred salinity, based on leave-one-out cross-validation, R2 = 0.64). This model and a previously published diatom–salinity model were both used to infer salinity levels in Tower Hill Lake in south-eastern Australia, over the last 60 years. Comparisons between these reconstructions and measured salinity data from Tower Hill Lake indicate that salinities inferred by the MIRS model more closely resembled the measured values than those produced using the diatom model, predominantly in terms of the actual values inferred, but also with regard to the trends observed. This supports the hypothesis that MIRS can provide a valuable new tool for reconstructing lake salinity.Laura Cunningham, John Tibby, Sean Forrester, Cameron Barr and Jan Skjemsta

Late Quaternary vegetation history of North Stradbroke Island, Queensland, eastern Australia

Currently there is a paucity of records of late Quaternary palaeoenvironmental variability available from the subtropics of Australia. The three continuous palaeoecological records presented here, from North Stradbroke Island, subtropical Queensland, assist in bridging this large spatial gap in the current state of knowledge. The dominance of arboreal taxa in the pollen records throughout the past >40,000 years is in contrast with the majority of records from temperate Australia, and indicates a positive moisture balance for North Stradbroke Island. The charcoal records show considerable inter-site variability indicating the importance of local-scale events on individual records, and highlighting the caution that needs to be applied when interpreting a single site as a regional record. The variability in the burning regimes is interpreted as being influenced by both climatic and human factors. Despite this inter-site variability, broad environmental trends are identifiable, with changes in the three records comparable with the OZ-INTIMATE climate synthesis for the last 35,000 years. © 2013 Elsevier Ltd.Patrick T. Moss, John Tibby, Lynda Petherick, Hamish McGowan, Cameron Bar

Validation of a method to partition the base deficit in meningococcal sepsis: a retrospective study

INTRODUCTION: The base deficit is a useful tool for quantifying total acid–base derangement, but cannot differentiate between various aetiologies. The Stewart–Fencl equations for strong ions and albumin have recently been abbreviated; we hypothesised that the abbreviated equations could be applied to the base deficit, thus partitioning this parameter into three components (the residual being the contribution from unmeasured anions). METHODS: The two abbreviated equations were applied retrospectively to blood gas and chemistry results in 374 samples from a cohort of 60 children with meningococcal septic shock (mean pH 7.31, mean base deficit -7.4 meq/L). Partitioning required the simultaneous measurement of plasma sodium, chloride, albumin and blood gas analysis. RESULTS: After partitioning for the effect of chloride and albumin, the residual base deficit was closely associated with unmeasured anions derived from the full Stewart–Fencl equations (r(2 )= 0.83, y = 1.99 – 0.87x, standard error of the estimate = 2.29 meq/L). Hypoalbuminaemia was a common finding; partitioning revealed that this produced a relatively consistent alkalinising effect on the base deficit (effect +2.9 ± 2.2 meq/L (mean ± SD)). The chloride effect was variable, producing both acidification and alkalinisation in approximately equal proportions (50% and 43%, respectively); furthermore the magnitude of this effect was substantial in some patients (SD ± 5.0 meq/L). CONCLUSION: It is now possible to partition the base deficit at the bedside with enough accuracy to permit clinical use. This provides valuable information on the aetiology of acid–base disturbance when applied to a cohort of children with meningococcal sepsis