bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of tephra falls on vegetation: A Late‐Quaternary record from southern Italy
Authors: Allen Judy R. M. , Huntley Brian 
Published: April 2018

Abstract

Impacts of tephra deposition on vegetation are recorded in a series of 10 high temporal resolution absolute pollen diagrams from Lago Grande di Monticchio, each diagram spanning a single tephra deposition event during the last glacial–interglacial cycle.

Sediment accumulation rates determined by counting and measurement of annual laminations (“varves”) provide an accurate and precise chronology, enabling the minimum recovery time after a tephra fall to be determined.

In most cases, pollen accumulation rate was reduced after the tephra fall, indicating reduced vegetation productivity. Tephra deposition events also led to changes in vegetation composition, although these varied in magnitude.

The magnitude and duration of the impacts upon the vegetation were related to the thickness of the tephra layer deposited, the thickest layers examined (>250 mm) having minimum recovery times of up to a century and thicker layers generally having greater impacts upon pollen productivity and vegetation composition.

Tephra chemistry also influenced the persistence of the impact.

The nature of the prevailing vegetation prior to the tephra fall influenced the degree and persistence of the impact. Tephra layers <30 mm thick had minimum recovery times of up to 90 years when they fell on wooded steppe vegetation, whereas cold steppe recovered much more quickly, as did forest.

The relative sensitivity of wooded steppe was contrary to our expectations.

Of individual pollen taxa, Cupressaceae emerged as particularly sensitive to tephra deposition.

Synthesis. Applying absolute pollen analytical methods to a sediment record with a well‐supported and precise chronology obtained from a lake in a volcanic region where the vegetation has been subject to numerous tephra deposition events enabled us to explore the impacts of such events. Our results provide evidence of differential impacts upon individual plant taxa and of differential sensitivity of three vegetation types that have prevailed in the region during the last glacial–interglacial cycle. The influences of tephra thickness and chemistry on minimum recovery time were substantial. Our results are relevant to forecasting the potential impacts upon ecosystems of volcanic eruptions.
Community and functional shifts in ammonia oxidizers across terrestrial and marine (soil/sediment) boundaries in two coastal Bay ecosystems
Authors: Zhang Li‐Mei , Duff Aoife M. , Smith Cindy J. 
Published: April 2018

SummaryTerrestrial–marine boundaries are significant sites of biogeochemical activity with delineated gradients from land to sea. While niche differentiation of ammonia‐oxidizing archaea (AOA) and bacteria (AOB) driven by pH and nitrogen is well known, the patterns and environmental drivers of AOA and AOB community structure and activity across soil‐sediment boundaries have not yet been determined. In this study, nitrification potential rate, community composition and transcriptional activity of AOA and AOB in soil, soil/sediment interface and sediments of two coastal Bays were characterized using a combination of field investigations and microcosm incubations. At DNA level, amoA gene abundances of AOA were significantly greater than AOB in soil, while in sediments AOB were significantly more abundant than AOA, but at the soil/sediment interface there were equal numbers of AOA and AOB amoA genes. Microcosm incubations provided further evidence, through qPCR and DGGE‐sequencing analysis of amoA transcripts, that AOA were active in soil, AOB in sediment and both AOA and AOB were active at the soil/sediment interface. The AOA and AOB community composition shifted across the coastal soil‐interface‐sediment gradient with salinity and pH identified as major environmental drivers.
Phenazine‐1‐carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces
Authors: LeTourneau Melissa K. , Marshall Matthew J. , Cliff John B. , Bonsall Robert F. , Dohnalkova Alice C. , Mavrodi Dmitri V. , Devi S. Indira , Mavrodi Olga V. , Harsh James B. , Weller David M. , Thomashow Linda S. 
Published: April 2018

SummaryPhenazine‐1‐carboxylic acid (PCA) is produced by rhizobacteria in dryland but not in irrigated wheat fields of the Pacific Northwest, USA. PCA promotes biofilm development in bacterial cultures and bacterial colonization of wheat rhizospheres. However, its impact upon biofilm development has not been demonstrated in the rhizosphere, where biofilms influence terrestrial carbon and nitrogen cycles with ramifications for crop and soil health. Furthermore, the relationships between soil moisture and the rates of PCA biosynthesis and degradation have not been established. In this study, expression of PCA biosynthesis genes was upregulated relative to background transcription, and persistence of PCA was slightly decreased in dryland relative to irrigated wheat rhizospheres. Biofilms in dryland rhizospheres inoculated with the PCA‐producing (PCA+) strain Pseudomonas synxantha 2‐79RN10 were more robust than those in rhizospheres inoculated with an isogenic PCA‐deficient (PCA‐) mutant strain. This trend was reversed in irrigated rhizospheres. In dryland PCA+ rhizospheres, the turnover of 15N‐labelled rhizobacterial biomass was slower than in the PCA‐ and irrigated PCA+ treatments, and incorporation of bacterial 15N into root cell walls was observed in multiple treatments. These results indicate that PCA promotes biofilm development in dryland rhizospheres, and likely influences crop nutrition and soil health in dryland wheat fields.
Seagrass rhizosphere microenvironment alters plant‐associated microbial community composition
Authors: Brodersen Kasper Elgetti , Siboni Nachshon , Nielsen Daniel A. , Pernice Mathieu , Ralph Peter J. , Seymour Justin , Kühl Michael 
Published: April 2018

SummaryThe seagrass rhizosphere harbors dynamic microenvironments, where plant‐driven gradients of O2and dissolved organic carbon form microhabitats that select for distinct microbial communities. To examine how seagrass‐mediated alterations of rhizosphere geochemistry affect microbial communities at the microscale level, we applied 16S rRNA amplicon sequencing of artificial sediments surrounding the meristematic tissues of the seagrassZostera muelleritogether with microsensor measurements of the chemical conditions at the basal leaf meristem (BLM). Radial O2loss (ROL) from the BLM led to ∼ 300 µm thick oxic microzones, wherein pronounced decreases in H2S and pH occurred. Significantly higher relative abundances of sulphate‐reducing bacteria were observed around the meristematic tissues compared to the bulk sediment, especially around the root apical meristems (RAM; ∼ 57% of sequences). Within oxic microniches, elevated abundances of sulphide‐oxidizing bacteria were observed compared to the bulk sediment and around the RAM. However, sulphide oxidisers within the oxic microzone did not enhance sediment detoxification, as rates of H2S re‐oxidation here were similar to those observed in a pre‐sterilized root/rhizome environment. Our results provide novel insights into how chemical and microbiological processes in the seagrass rhizosphere modulate plant‐microbe interactions potentially affecting seagrass health.
Metal contaminations impact archaeal community composition, abundance and function in remote alpine lakes
Authors: Compte‐Port Sergi , Borrego Carles M. , Moussard Hélène , Jeanbille Mathilde , Restrepo‐Ortiz Claudia Ximena , de Diego Alberto , Rodriguez‐Iruretagoiena Azibar , Gredilla Ainara , Fdez‐Ortiz de Vallejuelo Silvia , Galand Pierre E. , Kalenitchenko Dimitri , Rols Jean‐Luc , Pokrovsky Oleg S. , Gonzalez Aridane G. , Camarero Lluis , Muñiz Selene , Navarro‐Navarro Enrique , Auguet Jean‐Christophe 
Published: April 2018

SummaryUsing the 16S rRNA and mcrA genes, we investigated the composition, abundance and activity of sediment archaeal communities within 18 high‐mountain lakes under contrasted metal levels from different origins (bedrock erosion, past‐mining activities and atmospheric depositions). Bathyarchaeota, Euryarchaeota and Woesearchaeota were the major phyla found at the meta‐community scale, representing 48%, 18.3% and 15.2% of the archaeal community respectively. Metals were equally important as physicochemical variables in explaining the assemblage of archaeal communities and their abundance. Methanogenesis appeared as a process of central importance in the carbon cycle within sediments of alpine lakes as indicated by the absolute abundance of methanogen 16S rRNA and mcrA gene transcripts (105 to 109 copies g−1). We showed that methanogen abundance and activity were significantly reduced with increasing concentrations of Pb and Cd, two indicators of airborne metal contaminations. Considering the ecological importance of methanogenesis in sediment habitats, these metal contaminations may have system wide implications even in remote area such as alpine lakes. Overall, this work was pioneer in integrating the effect of long‐range atmospheric depositions on archaeal communities and indicated that metal contamination might significantly compromise the contribution of Archaea to the carbon cycling of the mountain lake sediments.
Laparoscopic management of choledochal cysts in infants and children: A review of current practice
Authors: Chan Edwin Kin‐Wai , Lee Kim‐Hung , Wong Vicky Hei‐Yi , Tsui Bess Siu‐Yan , Wong Sammi Yuen‐Shan , Pang Kristine Kit‐Yi , Mou Jennifer Wai‐Cheung , Tam Peter Yuk‐Him 
Published: April 2018

AimCholedochal cyst is characterized by congenital dilatation of the biliary system. Patients with choledochal cyst tend to be symptomatic in their childhood. The aim of this study was to review the current practice in laparoscopic management of choledochal cyst in infants and children.Patients and MethodsA PubMed database search was performed for all the studies on children who underwent laparoscopic excision of choledochal cyst. Additional literature was cited second hand from the first‐tier literatures.ResultsStudies on i) laparoscopic excision of choledochal cyst and hepaticojejunostomy in children; ii) laparoscopic management of choledochal cyst in antenatally detected choledochal cyst; iii) single incision laparoscopic surgery (SILS) in children with choledochal cyst; iv) robotic assisted laparoscopic surgery in children with choledochal cyst and v) hepaticoduodenostomy in children with choledochal cyst were reviewed.ConclusionsLaparoscopic excision of choledochal cyst and hepaticojejunostomy remains safe and feasible in children and infants. In centers experienced in MIS, SILS and robotic–assisted laparoscopy in the management of children with choledochal cyst were reported to be an alternative approach. The debate on hepaticoduodenostomy versus hepaticojejunostomy in biliary reconstruction will continue until a longterm outcome is available in the future.
Accuracy of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity score and the Nottingham risk score in hip fracture patients in Sweden — A prospective observational study
Authors: Jonsson M. H. , Bentzer P. , Turkiewicz A. , Hommel A. 
Published: April 2018

BackgroundLittle is known about accuracy of common risk prediction scores in elderly patients suffering from hip fractures. The objective of this study was to investigate accuracy of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) score, Portsmouth‐POSSUM (P‐POSSUM) score and the Nottingham Hip Fracture Score (NHFS) for prediction of mortality and morbidity in this patient group.MethodsThis was a prospective single centre observational study on 997 patients suffering out‐of‐hospital cervical, trochanteric or subtrochanteric fracture of the neck of the femur. Calibration and discrimination was assessed by calculating the ratio of observed to expected events (O:E) and areas under receiver operating characteristics curves (ROC).ResultsThe 30‐day mortality was 6.2% and complications, as defined by POSSUM, occurred in 41% of the patients. Overall O:E ratios for POSSUM, P‐POSSUM and NHFS scores for 30‐day mortality were 0.90, 0.98, and 0.79 respectively. The models underestimated mortality in the lower risk bands and overestimated mortality in the higher risk bands. In contrast, POSSUM predicted morbidity well with O:E ratios close to unity in most risk bands. The areas under the ROC curves for the scoring systems was 0.60‐0.67.ConclusionThe POSSUM score and NHFS show moderate calibration and poor discrimination in this cohort. The results suggest that mortality and morbidity in hip fracture patients are largely dependent on factors that are not included in these scores.
Health‐related quality of life after general surgical intensive care
Authors: Vogel G. , Forinder U. , Sandgren A. , Svensen C. , Joelsson‐Alm E. 
Published: April 2018

BackgroundImpaired mental and physical health are common complications after intensive care that could influence the patient's health‐related quality of life (HRQoL). Earlier research has mainly focused on HRQoL in mixed surgical and medical ICU populations. This study aimed to describe and analyze factors associated with HROoL after discharge from a general surgical ICU.MethodsA prospective cohort study was conducted in a general surgical ICU in Sweden between 2005 and 2012. Adult patients (≥18 years) with an ICU length of stay ≥96 hours were included. HRQoL was measured at 3, 6, and 12 months after discharge from the ICU using a questionnaire (SF‐36). A linear mixed model was used to analyze changes over time and Wilcoxon Signed Rank Tests were used to compare the 12‐months results to an age and gender matched reference population in Sweden. Linear regression analyses were performed to explore the impact on HRQoL from background variables.ResultsOf 447 patients eligible for the study, 276 patients (62%) answered SF‐36 at least once at 3, 6 or 12 months after ICU care and were included in the study. HRQoL improved over time but was still significantly lower at 12 months compared to the reference population. Female gender, age <75 years, living single, and ICU‐stay of more than 14 days were associated with lower HRQoL.ConclusionGeneral surgical ICU patients reports low HRQoL 1 year after ICU stay. The impaired HRQoL could be a long‐lasting problem with major consequences for the individual, family, and society.
Sleep in critically ill, mechanically ventilated patients with severe sepsis or COPD
Authors: Boyko Y. , Jennum P. , Oerding H. , Lauridsen J. T. , Nikolic M. , Toft P. 
Published: April 2018

BackgroundThe standard method for scoring polysomnographic (PSG) sleep is insufficient in the intensive care unit (ICU). A modified classification has been proposed, but has not been tested in specific groups of ICU patients. We aimed firstly to (1) use the modified classification to describe sleep in two groups of ICU patients: a severe sepsis group and a chronic obstructive pulmonary disease (COPD) group, and (2) to compare sleep stage distribution in the groups; secondly to compare the PSG findings with nurses’ sleep evaluation.MethodsNon‐sedated mechanically ventilated patients with severe sepsis or COPD completed up to 20‐hours PSG recording in each patient. A modified classification for scoring sleep in ICU was used for scoring the PSGs. Sleep assessment by nurses was done at 15 minutes intervals.ResultsWe included 16 patients with severe sepsis and 17 patients with COPD. Half of the patients in the severe sepsis group and 59% in the COPD group had atypical sleep. We found significantly different sleep stage distribution in the two groups, with the COPD group having a higher proportion of atypical sleep (54.4% vs 48.7%, P < .0001). No correlation between nurse sleep assessment and PSG was found in cases of atypical sleep (P < .0001).ConclusionNormal PSG sleep characteristics as defined by standard classification are absent in many conscious, non‐sedated critically ill patients on mechanical ventilation. Nurse sleep evaluation does not correlate with PSG if atypical sleep is present in the PSG, which limits the reliability of subjective sleep assessment in this patient population.
Citizen science in schools: Engaging students in research on urban habitat for pollinators
Authors: Saunders Manu E. , Roger Erin , Geary William L. , Meredith Floret , Welbourne Dustin J. , Bako Alex , Canavan Emily , Herro Francesca , Herron Charlotte , Hung Olivia , Kunstler Madeline , Lin Jade , Ludlow Natasha , Paton Mayling , Salt Sunny , Simpson Tallulah , Wang Ariana , Zimmerman Nikki , Drews Kalani B. , Dawson Hayley F. , Martin Lachlan W. J. , Sutton Jack B. , Webber Chiquita C. , Ritchie Amy L. , Berns Leigham D. , Winch Bella A. , Reeves Holly R. , McLennan Eiron C. , Gardner Jordan M. , Butler Charli G. , Sutton Emily I. , Couttie Max M. , Hildebrand Jake B. , Blackney Isabella A. , Forsyth Justine A. , Keating Deborah M. , Moles Angela T. 
Published: April 2018

AbstractCitizen science can play an important role in school science education. Citizen science is particularly relevant to addressing current societal environmental sustainability challenges, as it engages the students directly with environmental science and gives students an understanding of the scientific process. In addition, it allows students to observe local representations of global challenges. Here, we report a citizen science programme designed to engage school‐age children in real‐world scientific research. The programme used standardized methods deployed across multiple schools through scientist–school partnerships to engage students with an important conservation problem: habitat for pollinator insects in urban environments. Citizen science programmes such as the programme presented here can be used to enhance scientific literacy and skills. Provided key challenges to maintain data quality are met, this approach is a powerful way to contribute valuable citizen science data for understudied, but ecologically important study systems, particularly in urban environments across broad geographical areas.
Top predator fish assemblages in Northern Patagonia, Argentina. What factors regulate their patterns of distribution and abundance?
Authors: Fernández María Valeria , Lallement Mailén , Rechencq Magalí , Vigliano Pablo H. , Sosnovsky Alejandro , Macchi Patricio J. 
Published: April 2018

AbstractAccording to assemblage theory, three factors regulate fish biogeography: restriction of dispersion, environmental restrictions and biotic interactions. The first two factors act on a regional scale and delimit the area of action of the third, which operates on a local scale. Salmonid introductions began in Patagonia in 1904, and this has led to a restructuring of trophic webs and an increase in the number of top predators. This situation allowed us to evaluate, in a natural setting, how communities are formed on different geographic scales. We studied two large basins in Patagonia, situated close to each other but with different assemblages of top predatory fish. We hypothesized that differences in the structuring of the top predator assemblages between and within the basins are due to 1) environmental factors and dispersion processes facilitated by connectivity on a regional scale; and 2) biotic interaction (internal dynamics) between native perch and salmonids, the former acting as a modulator of the top predator assemblages on a local scale. To test these hypotheses, we analysed the top predator assemblages of 16 lakes and one reservoir, as well as their environmental characteristics. We performed a cluster analysis and related the resulting assembly groups to environmental factors by means of a tree model. We also analysed fish diets, using a similarities test to study biotic interactions. On regional and local scales, water basin, degree of connectivity, area, temperature and Zoogeographic integrity coefficient (ZIC) were important factors in the structuring of top predator assemblages. On a local scale, creole perch modulates the salmonid populations through feeding and the consequent distribution of resources. Our work showed that the structure of top predator assemblages was determined by a combination of local and regional factors acting in synergy, as postulated by the assemblage theory.
Videolaryngoscopy vs. fibreoptic bronchoscopy for awake tracheal intubation: a systematic review and meta‐analysis
Authors: Alhomary M. , Ramadan E. , Curran E. , Walsh S. R. 
Published: April 2018

SummaryAwake fibreoptic intubation is often considered the technique of choice when a difficult airway is anticipated. However, videolaryngoscopes are being used more commonly. We searched the current literature and performed a meta‐analysis to compare the use of videolaryngoscopy and fibreoptic bronchoscopy for awake tracheal intubation. Our primary outcome was the time needed to intubate the patient's trachea. Secondary outcomes included: failed intubation; the rate of successful intubation at the first attempt; patient‐reported satisfaction with the technique; and any complications resulting from intubation. Eight studies examining 429 patients were included in this review. The intubation time was shorter when videolaryngoscopy was used instead of fibreoptic bronchoscopy (seven trials, 408 participants, mean difference (95%CI) −45.7 (−66.0 to −25.4) s, p < 0.0001, low‐quality evidence). There was no significant difference between the two techniques in the failure rate (six studies, 355 participants, risk ratio (95%CI) 1.01 (0.24–4.35), p = 0.99, low‐quality evidence) or the first‐attempt success rate (six studies, 391 participants, risk ratio (95%CI) 1.01 (0.95–1.06), p = 0.8, moderate quality evidence). The level of patient satisfaction was similar between both groups. No difference was found in two reported adverse events: hoarseness/sore throat (three studies, 167 participants, risk ratio (95%CI) 1.07 (0.62–1.85), p = 0.81, low‐quality evidence), and low oxygen saturation (five studies, 337 participants, risk ratio (95%CI) 0.49 (0.22–1.12), p = 0.09, low‐quality evidence). In summary, videolaryngoscopy for awake tracheal intubation is associated with a shorter intubation time. It also seems to have a success rate and safety profile comparable to fibreoptic bronchoscopy.