Search

Aim: A 23-hour Care Centre was created at a principal referral hospital in Sydney in 2003. Its primary aim was to provide efficient and high quality care to patients requiring a brief stay in hospital for surgical or medical procedures, within one coordinated unit. Design: The features underlying the 23-hour Care Centre as an innovative model of care were the clinical guideline driven approach and nurse-initiated discharge. Sample: All patients, emergency and elective as well as surgical and medical, who fitted the following criteria were admitted as '23-hour patients' to the Centre. The criteria were: absolute expectation of discharge within 24 hours; pre-admission screening by a nurse screener (if elective admission): agreed clinical guideline in place; and, agreement to protocol-based, nurse-initiated discharge. Results: Following the first three months of the 23-hour Care Centre, 1601 patients utilised the 23-hour Care Centre as follows: 593 day only patients, 410 DOSA (day of surgery admission) patients and 598 23-hour patients. Excluding inappropriate admissions, overall discharge compliance was 83%. Conclusion: From the results generated throughout the trial it has become evident that the new clinical area offers a workable system of health care delivery for patients who require a brief stay in hospital, as it promotes an efficient use of hospital beds and services without compromising patient outcomes. However, further research is required to compare the efficiency and outcomes of care directly with that provided by the traditional inpatient hospital system. [ABSTRACT FROM AUTHOR]

Climate change is disproportionately impacting mountain ecosystems, leading to large reductions in winter snow cover, earlier spring snowmelt and widespread shrub expansion into alpine grasslands. Yet, the combined effects of shrub expansion and changing snow conditions on abiotic and biotic soil properties remains poorly understood. We used complementary field experiments to show that reduced snow cover and earlier snowmelt have effects on soil microbial communities and functioning that persist into summer. However, ericaceous shrub expansion modulates a number of these impacts and has stronger belowground effects than changing snow conditions. Ericaceous shrub expansion did not alter snow depth or snowmelt timing but did increase the abundance of ericoid mycorrhizal fungi and oligotrophic bacteria, which was linked to decreased soil respiration and nitrogen availability. Our findings suggest that changing winter snow conditions have cross‐seasonal impacts on soil properties, but shifts in vegetation can modulate belowground effects of future alpine climate change. [ABSTRACT FROM AUTHOR]

Much of the emphasis on gaining efficiencies in surgical care have, to date, focused on increasing day only (DO) facilities and increasing the utilization of day of surgery admissions (DOSA) for longer stay cases. However, for the majority of cases requiring surgery, both elective and acute, the episode of care can generally be delivered within an envelope of 23 h during which time patients require only pain relief and monitoring in a supervised setting until fit for discharge. The aim of the present study was to evaluate a pilot of a 23-h care centre at a principal referral hospital.A 23-h care centre was established at a principal referral hospital in January 2003 in association with an existing DO and DOSA facility. All patients, both emergency and elective as well as surgical and medical, who fitted the following criteria were admitted as‘23-h patients’ to the centre: absolute expectation of discharge within 24 h; preadmission screening by a nurse screener (if elective); agreed clinical guidelines in place; agreement to protocol-based, nurse-initiated discharge. Outcomes were evaluated after 3 months. Existing admission criteria for DO and DOSA patients were maintained.Over 3 months, 1601 patients utilized the 23-h care centre as follows: 593 DO patients, 410 DOSA patients and 598 23-h patients. Transfers from the emergency department constituted 47% of all 23-h patients. Utilization varied with the departments of hand surgery, ear, nose and throat/head and neck surgery, and gastrointestinal surgery all managing more than 55% of their operative workload as 23-h patients (excluding DO and DOSA patients). Excluding inappropriate admissions, overall discharge compliance was 83%. Three departments achieved the compliance benchmark of 90% of admitted patients discharged within 23 h. Only 1% of patients discharged required referral back to the emergency department, with a further 2% being reviewed by their general practitioner.The 23-h care centre model, incorporating DO, DOSA and 23-h patients, offers a workable system of healthcare delivery for patients who do not require a prolonged stay in hospital including, potentially, the majority of surgical patients. [ABSTRACT FROM AUTHOR]

Human activities have massively increased the amount of reactive nitrogen in the biosphere, which is leading to increased nitrogen (N) inputs in terrestrial ecosystems. The retention of N is a crucial ecosystem function of both managed and natural ecosystems, and there is a long history of experimental, observational, and conceptual studies identifying its major controls. Yet, the plant and soil microbial controls on the retention of added N remain elusive.Here, we used three ecosystem chronosequences in front of retreating glaciers in the European Alps to test our hypothesis that the retention of added reactive 15N increases as succession proceeds, and to identify the plant and microbial controls on ecosystem N retention.We found that the uptake and retention of N did not change during succession, despite consistent changes in plant, soil, and microbial properties with increasing time since deglaciation. Instead, we found that plant and microbial properties that remained constant during succession controlled 15N uptake and retention: low root and microbial C/N ratios, as well as high root biomass, increased plant and microbial uptake of added N. In addition, high soil concentrations of nitrate and ammonium reduced the uptake of N in microbes and roots, respectively.Synthesis. Our results demonstrate that plant and microbial N demand, as well as soil N availability, drive the short‐term retention of added N during succession in glacier forelands. This finding represents an advance in our understanding of the fundamental controls on ecosystem N retention and the role of plant‐microbial interactions in this process. Such understanding is crucial for predicting and mitigating the response of terrestrial ecosystems to the ever‐increasing amounts of reactive N in the biosphere. [ABSTRACT FROM AUTHOR]

In contrast to the situation in plants inhabiting most of the world's ecosystems, mycorrhizal fungi are usually absent from roots of the only two native vascular plant species of maritime Antarctica, Deschampsia antarctica and Colobanthus quitensis. Instead, a range of ascomycete fungi, termed dark septate endophytes (DSEs), frequently colonise the roots of these plant species. We demonstrate that colonisation of Antarctic vascular plants by DSEs facilitates not only the acquisition of organic nitrogen as early protein breakdown products, but also as non‐proteinaceous d‐amino acids and their short peptides, accumulated in slowly‐decomposing organic matter, such as moss peat. Our findings suggest that, in a warming maritime Antarctic, this symbiosis has a key role in accelerating the replacement of formerly dominant moss communities by vascular plants, and in increasing the rate at which ancient carbon stores laid down as moss peat over centuries or millennia are returned to the atmosphere as CO2. [ABSTRACT FROM AUTHOR]

Background and aims: Belowground C supply from plant roots may accelerate the decomposition of SOM through the rhizosphere priming effect, but the detailed interaction between substrate quality and rhizosphere C supply is poorly understood. We hypothesize that decomposition of organic matter is enhanced by the combined effect of assimilate C supply to the rhizosphere and substrate amendments. Methods: Birch trees (Betula pendula) planted in experimental mesocosms; half of these trees were shaded to reduce the supply of assimilate C to roots and ECM fungi. Either 13C-enriched glucose, straw, fungal necromass or C4 biochar were subsequently added to each mesocosm. CO2 efflux derived from substrates were separated from that derived from native SOM and roots based on the isotopic composition of total respired CO2. Results: The addition of all substrates increased fluxes in both un-shaded and shaded treatments, with greatest total CO2 efflux observed in soils amended with straw. Increases in un-labelled CO2 were observed to be greater in the presence of belowground C supply than in mesocosms with shaded trees. Conclusions: Turnover of SOM is closely linked to belowground C allocation. The biochemical quality and recalcitrance of litter entering the soil C pool is of critical importance to this priming, as is the interaction with rhizosphere-associated decomposition activity. [ABSTRACT FROM AUTHOR]

Stable carbon isotope analysis of pollen provides potential for reconstruction of past moisture availability in the environment on longer time-scales compared to isotope analysis of plant tissue. Here we show that the carbon isotopic compositions (δ 13 C) of pollen, sporopollenin, leaf and stem tissues of Cedrus atlantica are strongly related. Untreated pollen δ 13 C has a significant linear relationship with sporopollenin δ 13 C (r 2 = 0.97, p < 0.0001) which is relatively depleted in 13 C by an average 1.5‰. Carbon isotope discrimination (Δ 13 C) by sporopollenin (derived from pollen δ 13 C values) is related to mean annual (r 2 = 0.54, p < 0.001) and summer precipitation (r 2 = 0.63, p < 0.0001). A 100 mm increase in mean annual precipitation results in sporopollenin Δ 13 C increasing by 0.52‰, or by 1.4‰ per 100 mm summer precipitation. There is a stronger relationship between sporopollenin Δ 13 C and long-term annual scPDSI (r 2 = 0.86, p < 0.0001) and summer scPDSI (r 2 = 0.86, p < 0.001) aridity indexes, with reduced Δ 13 C as aridity increases. These relationships suggest that stable carbon isotope analysis of C. atlantica fossil pollen could be used as a quantitative proxy for the reconstruction of summer moisture availability in Northwest Africa. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) from agricultural soil is a significant source of greenhouse gas emissions. Biochar amendment can contribute to climate change mitigation by suppressing emissions of N2O from soil, although the mechanisms underlying this effect are poorly understood. We investigated the effect of biochar on soil N2O emissions and N cycling processes by quantifying soil N immobilisation, denitrification, nitrification and mineralisation rates using 15N pool dilution techniques and the FLUAZ numerical calculation model. We then examined whether biochar amendment affected N2O emissions and the availability and transformations of N in soils. Our results show that biochar suppressed cumulative soil N2O production by 91% in near-saturated, fertilised soils. Cumulative denitrification was reduced by 37%, which accounted for 85-95% of soil N2O emissions. We also found that physical/chemical and biological ammonium (NH4+) immobilisation increased with biochar amendment but that nitrate (NO3−) immobilisation decreased. We concluded that this immobilisation was insignificant compared to total soil inorganic N content. In contrast, soil N mineralisation significantly increased by 269% and nitrification by 34% in biochar-amended soil. These findings demonstrate that biochar amendment did not limit inorganic N availability to nitrifiers and denitrifiers, therefore limitations in soil NH4+ and NO3− supply cannot explain the suppression of N2O emissions. These results support the concept that biochar application to soil could significantly mitigate agricultural N2O emissions through altering N transformations, and underpin efforts to develop climate-friendly agricultural management techniques. [ABSTRACT FROM AUTHOR]

Background and aims: Acacia senegal, a leguminous dryland tree, is economically and ecologically important to sub-Saharan Africa. Water-use efficiency (WUE) and biological nitrogen fixation (BNF) are fundamental to plant productivity and survival. We quantify provenance differences in WUE, BNF, photosynthesis, biomass and gum arabic production from A. senegal assessing genetic improvement potential. Methods: Using stable isotope ratios, we determined WUE (δC) and BNF (δN) from provenances of mature A. senegal in field-trials (Senegal), sampling leaves at the beginning (wet) and end (dry) of the rainy season. Seedling provenance trials (UK) determined photosynthesis, and biomass and δC in relation to water table. Environmental data were characterised for all provenances at their sites of origin. Results: Provenances differed in both δC and δN. Gum yield declined with increasing WUE. Virtually no BNF was detected during the dry season and seedlings and mature trees may have different WUE strategies. Wind speed and soil characteristics at provenance origin were correlated with isotope composition and gum production. Conclusion: Provenance differences suggest that selection for desirable traits, e.g., increased gum production, may be possible. As ecological strategies relate to native locality, the environmental conditions at plantation site and provenance origin are important in assessing selection criteria. [ABSTRACT FROM AUTHOR]

We measured the effect of elevated atmospheric CO on atmospheric nitrogen (N) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N fixation in A. glutinosa will increase in response to increased atmospheric CO concentrations, when growing in monoculture, (2) the impact of elevated CO on N fixation in A. glutinosa is the same in mixture and in monoculture and (3) the impacts of elevated CO on N cycling will be evident by a decrease in leaf δN and by the soil-leaf enrichment factor (EF), and that these impacts will not differ between mixed and single species stands. Trees were grown in a forest plantation on former agricultural fields for four growing seasons, after which the trees were on average 3.8 m tall and canopy closure had occurred. Atmospheric CO concentrations were maintained at either ambient or elevated (by 200 ppm) concentrations using a free-air CO enrichment (FACE) system. Leaf δN was measured and used to estimate the amount (N) and proportion (%N) of N derived from atmospheric fixation. On average, 62% of the N in A. glutinosa leaves was from fixation. The %N and N for A. glutinosa trees in monoculture did not increase under elevated CO, despite higher growth rates. However, N fixation did increase for trees growing in mixture, despite the absence of significant growth stimulation. There was evidence that fixed N was transferred from A. glutinosa to F. sylvatica and B. pendula, but no evidence that this affected their CO response. The results of this study show that N fixation in A. glutinosa may be higher in a future elevated CO world, but that this effect will only occur where the trees are growing in mixed species stands. [ABSTRACT FROM AUTHOR]

Microbial necromass dominates soil organic matter. Recent research on necromass and soil carbon storage has focused on necromass production and stabilization mechanisms but not on the mechanisms of necromass retention. We present evidence from soil incubations with stable-isotope labeled necromass that abiotic adsorption may be more important than biotic immobilization for short-term necromass retention. We demonstrate that necromass adsorbs not only to mineral surfaces, but may also interact with other necromass. Furthermore, necromass cell chemistry alters necromass-necromass interaction, with more bacterial tracer retained when there is yeast necromass present. These findings suggest that the adsorption and abiotic interaction of microbial necromass and its functional properties, beyond chemical stability, deserve further investigation in the context of soil carbon sequestration. The fate of microbial necromass in mineral soils. Image 1 • Abiotic adsorption of isotopically-labeled necromass exceeds biotic immobilization. • Abiotic processes include mineral-organic sorption and organic-organic interactions. • Necromass chemistry matters: Gram-negative bacteria retained more with yeast. • Abiotic microbial biomass materials have properties important for global soil carbon sequestration. [ABSTRACT FROM AUTHOR]

In grasslands, N mineralization and nitrification are important processes and are controlled by several factors, including the in situ microbial community composition. Nitrification involves ammonia oxidising archaea (AOA) and bacteria (AOB) and although AOA and AOB co-exist in soils, they respond differently to environmental characteristics and there is evidence of AOA/AOB niche differentiation. Here, we investigated temporal variation in N mineralization and nitrification rates, together with bacterial, archaeal and ammonia-oxidiser communities in grassland soils, on different geologies: clay, Greensand and Chalk. Across geologies, N mineralization and nitrification rates were slower in the autumn than the rest of the year. Turnover times for soil ammonium pools were <24 h, whilst several days for nitrate. In clay soils, bacterial, archaeal, AOA, and AOB communities were clearly distinct from those in Chalk and Greensand soils. Spatially and temporally, AOA were more abundant than AOB. Notably, Nitrososphaera were predominant, comprising 37.4% of archaeal communities, with the vast majority of AOA found in Chalk and Greensand soils. AOA abundance positively correlated with nitrate concentration, whereas AOB abundance correlated with ammonium and nitrite concentrations, suggesting that these N compounds may be potential drivers for AOA/AOB niche differentiation in these grassland soils. • Turnover times for soil ammonium were <24 h, whilst several days for nitrate. • AOA and AOB communities in clay were clearly distinct from those in chalk and greensand soils. • Generally, ammonia oxidising archaea were more abundant than ammonia oxidising bacteria. • AOA abundance positively correlated with nitrate, whereas AOB abundance correlated with ammonium and nitrite concentrations. • This study showed additional evidence for niche differentiation among ammonia-oxidisers in grasslands. [ABSTRACT FROM AUTHOR]

Forests have a key role as carbon sinks, which could potentially mitigate the continuing increase in atmospheric carbon dioxide concentration and associated climate change. We show that carbon dioxide enrichment, although causing short-term growth stimulation in a range of European tree species, also leads to an increase in soil microbial respiration and a marked decline in sequestration of root-derived carbon in the soil. These findings indicate that, should similar processes operate in forest ecosystems, the size of the annual terrestrial carbon sink may be substantially reduced, resulting in a positive feedback on the rate of increase in atmospheric carbon dioxide concentration. [ABSTRACT FROM AUTHOR]

Aims: Elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties are a suggested risk factor for developing cardiovascular complications including cardiomyopathy. Clinical studies assessing patients with MoM hips using left ventricular ejection fraction (LVEF) have found conflicting evidence of cobalt-induced cardiomyopathy. Global longitudinal strain (GLS) is an echocardiography measurement known to be more sensitive than LVEF when diagnosing early cardiomyopathies. The extent of cardiovascular injury, as measured by GLS, in patients with elevated blood cobalt levels has not previously been examined., Methods: A total of 16 patients with documented blood cobalt ion levels above 13 µg/l (13 ppb, 221 nmol/l) were identified from a regional arthroplasty database. They were matched with eight patients awaiting hip arthroplasty. All patients underwent echocardiography, including GLS, investigating potential signs of cardiomyopathy., Results: Patients with MoM hip arthroplasties had a mean blood cobalt level of 29 µg/l (495 nmol/l) compared to 0.01 µg/l (0.2 nmol/l) in the control group. GLS readings were available for seven of the MoM cohort, and were significantly lower when compared with controls (-15.5% vs -18% (MoM vs control); p = 0.025)). Pearson correlation demonstrated that GLS significantly correlated with blood cobalt level ( r = 0.8521; p < 0.001). However, there were no differences or correlations for other echocardiography measurements, including LVEF (64.3% vs 63.7% (MoM vs control); p = 0.845)., Conclusion: This study supports the hypothesis that patients with elevated blood cobalt levels above 13 µg/l in the presence of a MoM hip implant may have impaired cardiac function compared to a control group of patients awaiting hip arthroplasty. It is the first study to use the more sensitive parameter of GLS to assess for any cardiac contractile dysfunction in patients with a MoM hip implant and a normal LVEF. Larger studies should be performed to determine the potential of GLS as a predictor of cardiac complications in patients with MoM arthroplasties., Competing Interests: S. Currie and M. Jenkinson report that this study was supported by a Heart Research UK project grant (ref RG2675/18/20). R. M. D. Meek reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Stryker and Palacdemy, and an annual stipend for a Specialty Editor role on The Bone & Joint Journal, all of which are unrelated to this study., (© 2024 The British Editorial Society of Bone & Joint Surgery.)

The seasonal coupling of plant and soil microbial nutrient demands is crucial for efficient ecosystem nutrient cycling and plant production, especially in strongly seasonal alpine ecosystems. Yet, how these seasonal nutrient cycling processes are modified by climate change and what the consequences are for nutrient loss and retention in alpine ecosystems remain unclear. Here, we explored how two pervasive climate change factors, reduced snow cover and shrub expansion, interactively modify the seasonal coupling of plant and soil microbial nitrogen (N) cycling in alpine grasslands, which are warming at double the rate of the global average. We found that the combination of reduced snow cover and shrub expansion disrupted the seasonal coupling of plant and soil N-cycling, with pronounced effects in spring (shortly after snow melt) and autumn (at the onset of plant senescence). In combination, both climate change factors decreased plant organic N-uptake by 70% and 82%, soil microbial biomass N by 19% and 38% and increased soil denitrifier abundances by 253% and 136% in spring and autumn, respectively. Shrub expansion also individually modified the seasonality of soil microbial community composition and stoichiometry towards more N-limited conditions and slower nutrient cycling in spring and autumn. In winter, snow removal markedly reduced the fungal:bacterial biomass ratio, soil N pools and shifted bacterial community composition. Taken together, our findings suggest that interactions between climate change factors can disrupt the temporal coupling of plant and soil microbial N-cycling processes in alpine grasslands. This could diminish the capacity of these globally widespread alpine ecosystems to retain N and support plant productivity under future climate change., (© 2024 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Introduction: Out of hospital cardiac arrest (OHCA) is a common problem. Rates of survival are low and a proportion of survivors are left with an unfavourable neurological outcome. Four models have been developed to predict risk of unfavourable outcome at the time of critical care admission - the Cardiac Arrest Hospital Prognosis (CAHP), MIRACLE 2 , Out of Hospital Cardiac Arrest (OHCA), and Targeted Temperature Management (TTM) models. This evaluation evaluates the performance of these four models in a United Kingdom population and provides comparison to performance of the Acute Physiology and Chronic Health Evaluation II (APACHE-II) score., Methods: A retrospective evaluation of the performance of the models was conducted over a 43-month period in 414 adult, non-pregnant patients presenting consecutively following non-traumatic OHCA to the five units in our regional critical care network. Scores were generated for each model for where patients had complete data (CAHP = 347, MIRACLE 2  = 375, OHCA = 356, TTM = 385). Cerebral Performance Category (CPC) outcome was calculated for each patient at last documented follow up and an unfavourable outcome defined as CPC ⩾ 3. Performance for discrimination of unfavourable outcome was tested by generating receiver operating characteristic (ROC) curves for each model and comparing the area under the curve (AUC)., Results: Best performance for discrimination of unfavourable outcome was demonstrated by the high risk group of the CAHP score with an AUC of 0.87 [95% CI 0.83-0.91], specificity of 97.1% [95% CI 93.8-100] and positive predictive value (PPV) of 96.3% [95% CI 92.2-100]. The high risk group of the MIRACLE 2 model, which is significantly easier to calculate, had an AUC of 0.81 [95% CI 0.76-0.86], specificity of 92.3% [95% CI 87.2-97.4] and PPV of 95.2% [95% CI 91.9-98.4]., Conclusion: The CAHP, MIRACLE 2 , OHCA and TTM scores all perform comparably in a UK population to the original development and validation cohorts. All four scores outperform APACHE-II in a population of patients resuscitated from OHCA. CAHP and TTM perform best but are more complex to calculate than MIRACLE 2 , which displays inferior performance., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Intensive Care Society 2023.)

The carbon cycle is a key regulator of Earth's climate. On geological time-scales, our understanding of particulate organic matter (POM), an important upper ocean carbon pool that fuels ecosystems and an integrated part of the carbon cycle, is limited. Here we investigate the relationship of planktonic foraminifera-bound organic carbon isotopes (δ 13 C org-pforam ) with δ 13 C org of POM (δ 13 C org-POM ). We compare δ 13 C org-pforam of several planktonic foraminifera species from plankton nets and recent sediment cores with δ 13 C org-POM on a N-S Atlantic Ocean transect. Our results indicate that δ 13 C org-pforam of planktonic foraminifera are remarkably similar to δ 13 C org-POM . Application of our method on a glacial sample furthermore provided a δ 13 C org-pforam value similar to glacial δ 13 C org-POM predictions. We thus show that δ 13 C org-pforam is a promising proxy to reconstruct environmental conditions in the upper ocean, providing a route to isolate past variations in δ 13 C org-POM and better understanding of the evolution of the carbon cycle over geological time-scales., (© 2022. The Author(s).)