Remarkable insights into the paleoecology of the Avalonian Ediacaran macrobiota

Ediacaran macrofossils from the Avalon Terrane (primarily eastern Newfoundland and the central UK) record some of the earliest large and complex multicellular organisms on Earth. Perhaps the greatest unknown regarding these fossils is their relevance to the early evolutionary history of the Kingdom Animalia. In recent years, new data and discoveries have revealed insights into Ediacaran paleobiology, taxonomic relationships, paleoecology and taphonomy, significantly refining our understanding of Avalonian ecosystems. Here, we summarise recent observational and quantitative studies, and their bearing on the current understanding of Avalonian benthic marine ecosystems. A review of existing knowledge of the biological composition of Avalonian marine assemblages demonstrates that they record densely-populated ecosystems inhabited by a diverse range of organisms, likely representing multiple biological Kingdoms. Appreciation of this diversity, and of the complexities it introduces to paleoecological studies, is vital when considering the relationship between macroevolution and contemporaneous climatic, tectonic and geochemical events. We then summarise current understanding of Avalonian paleoecology. Studies into locomotion, reproduction, feeding strategies, and community structure and succession reveal that these ecosystems were considerably different to Phanerozoic settings. Furthermore, we suggest that Avalonian ecosystems witnessed the appearance of novel nutrient sources, offering new opportunities and niches for benthic organisms. The suggestion that the numerically dominant rangeomorphs were osmotrophic is reviewed and appraised in light of geochemical, morphological, and biological information. Finally, the use of modern ecological metrics in the study of Ediacaran fossil assemblages is assessed. Concerns regarding the interpretation of paleoecological data are outlined in light of current taphonomic and sedimentological understanding, and these cast doubt on previous suggestions that the Avalonian assemblages were largely composed of metazoans. Nevertheless, we emphasise that if treated with necessary caution, paleoecological data can play a significant role in assisting efforts to determine the biological affinities of late Ediacaran macroscopic organisms.Thanks are extended to the editors of Gondwana Research, T. Horscroft and M. Santosh, for inviting this review, and for their patience whilst we completed it. The Parks and Natural Areas Division, Department of Environment and Conservation, Government of Newfoundland and Labrador provided permits to conduct research within the Mistaken Point Ecological Reserve between 2008–2013, whilst the Department of Tourism, Culture and Recreation provided permits for paleontological research in other parts of the Province from 2012–2013. The support of the Portugal Cove South Visitor Center interpreters during our field research was greatly appreciated. This work has been supported by the Natural Environment Research Council [grant numbers NE/I005927/1 to CGK and NE/G523539/1 to EGM]; a Henslow Junior Research Fellowship from Cambridge Philosophical Society to AGL; and the National Geographic Global Exploration Fund [GEFNE 22-11 to AGL]. Field assistance from J. Matthews, J. Stewart, D. Collins, and T. Hearing has been invaluable, and we have enjoyed fruitful discussions on this topic with N. Butterfield, D. McIlroy, J. Hoyal Cuthill, M. Brasier, S. Conway Morris and P. Wilby. The work and support of past and current workers in this field is gratefully acknowledged. B. MacGabhann and one anonymous reviewer are thanked for providing detailed comments that have strengthened this manuscript, whilst S. Jensen and M. Friedman provided helpful feedback on parts of this manuscript assessed as a chapter of AGL's thesis.This is the final published version of an article that was originally published in Gondwana Research, Available online 4 December 2014, doi:10.1016/j.gr.2014.11.00

Ediacaran marine animal forests and the ventilation of the oceans

The rise of animals across the Ediacaran–Cambrian transition marked a step-change in the history of life, from a microbially-dominated world to the complex macroscopic biosphere we see today. While the importance of bioturbation and swimming in altering the structure and function of Earth systems is well established, the influence of epifaunal animals on the hydrodynamics of marine environments is not well understood. Of particular interest are the oldest ‘marine animal forests’, which comprise a diversity of sessile soft-bodied organisms dominated by the fractally-branching rangeomorphs. Typified by fossil assemblages from the Ediacaran of Mistaken Point, Newfoundland, these ancient communities might have played a pivotal role in structuring marine environments, similar to modern ecosystems, but our understanding of how they impacted fluid flow in the water column is limited. Here, we use ecological modelling and computational flow simulations to explore how Ediacaran marine animal forests influenced their surrounding environment. Our results reveal how organism morphology and community structure and composition combined to impact vertical mixing of the surrounding water. We find that Mistaken Point communities were capable of generating high-mixing conditions, thereby likely promoting gas and nutrient transport within the ‘canopy’. This mixing could have served to enhance local-scale oxygen concentrations and redistribute resources like dissolved organic carbon. Our work suggests that Ediacaran marine animal forests may have contributed to the ventilation of the oceans over 560 million years ago, well before the Cambrian explosion of animals

Piloting a parent and patient decision aid to support clinical trial decision making in childhood cancer

Objective: Families of a child with cancer can find the decision to enrol in a clinical trial challenging and often misunderstand key concepts that underpin trials. We pilot tested “Delta,” an online and booklet decision aid for parents with a child with cancer, and adolescents with cancer, deciding whether or not to enrol in a clinical trial. Methods: We developed Delta in accordance with the International Patient Decision Aid Standards. We conducted a pre-post pilot with parents with a child, and adolescents, who had enrolled in a paediatric phase III clinical trial for newly diagnosed acute lymphoblastic leukaemia. Parents (n = 37) and adolescents (n = 3) completed a questionnaire before and after using Delta (either the website or booklet, based on their preference). Results: Twenty-three parents (62.2%) and three adolescents (100%) reviewed the Delta website. Parents rated Delta as highly acceptable in regard to being clearly presented, informative, easy to read, useful, visually appealing, and easy to use. All participants reported that they would recommend Delta to others and that it would have been useful when making their decision. Parents' subjective (Mdiff=10.8, SDdiff = 15.69, P <.001) and objective (OR = 2.25, 95% CI, 1.66-3.04; P <.001) clinical trial knowledge increased significantly after reviewing Delta. Conclusions: To our knowledge, Delta is the first reported decision aid, available online and as a booklet, for parents and adolescents deciding whether or not to enrol in a paediatric oncology clinical trial. Our study suggests that Delta is acceptable, feasible, and potentially useful

Non-palimpsested crowded Skolithos ichnofabrics in a Carboniferous tidal rhythmite: Disentangling ecological signatures from the spatio-temporal bias of outcrop

Funder: International Association of Sedimentologists; Id: http://dx.doi.org/10.13039/501100007463A heterolithic tidalite succession yielding spring–neap bundles is newly reported from a mid- Carboniferous (Serpukhovian) section of the Alston Formation of Northumberland, England. The rhythmite records deposition over an interval that can be confidently calibrated to at least 84 lunar days, and attests to a non-negligible tidal range in parts of the Northwest European Seaway in the late Mississippian. The tidalite is notable for the presence of a striking crowded Skolithos ichnofabric on both bedding planes and in vertical section. Bedding plane expressions of the ichnofabric reveal true substrates of sand piles excavated during burrow construction, in addition to an apparently remarkable equal spacing between individual burrows that is shown to be genuine through pair correlation function analysis. These characteristics show that the burrowed horizons were registered by contemporaneous ichnocoenoses, with no palimpsesting of burrows. The irregular vertical distribution of burrow horizons, despite a near-continuous semi-diurnal record of sedimentation, is suggested to be an artefact of spatial patchiness of burrowing communities in the depositional environment; imperfectly registered in a vertical profile with high-temporal, lowspatial resolution. The succession proves that burrow palimpsesting is not an inevitable ichnological conclusion of sedimentary stasis, and attests to intermittent palaeoecological fidelity of the stratigraphic record at the small spatio-temporal scales recorded a

Effect of pregnancy prolongation in early-onset pre-eclampsia on postpartum maternal cardiovascular, renal and metabolic function in primiparous women: an observational study.

OBJECTIVE: To evaluate the association between deferred delivery in early-onset pre-eclampsia and offspring outcome and maternal cardiovascular, renal and metabolic function in the postpartum period. DESIGN: Observational study. SETTING: Tertiary referral hospital. POPULATION: Nulliparous women diagnosed with pre-eclampsia before 34 weeks' gestation who participated in a routine postpartum cardiovascular risk assessment programme. Women with hypertension, diabetes mellitus or renal disease prior to pregnancy were excluded. METHODS: Regression analyses were performed to assess the association between pregnancy prolongation and outcome measures. MAIN OUTCOME MEASURES: Offspring outcome and prevalence of deviant maternal cardiovascular, renal and metabolic function. RESULTS: The study population included 564 women with a median pregnancy prolongation of 10 days (interquartile range [IQR] 4-18) who were assessed at on average 8 months (IQR 6-12) postpartum. Pregnancy prolongation after diagnosis resulted in a decrease in infant mortality (adjusted odd ratio [aOR] 0.907, 95% CI 0.852-0.965 per day prolongation). This improvement in offspring outcome was associated with an elevated risk of moderately increased albuminuria (aOR 1.025, 95% CI 1.006-1.045 per day prolongation), but not with aberrant cardiac geometry, cardiac systolic or diastolic dysfunction, persistent hypertension or metabolic syndrome. CONCLUSION: Pregnancy prolongation in early-onset pre-eclampsia is associated with improved offspring outcome and survival. These effects do not appear to be deleterious to short-term maternal cardiovascular and metabolic function but are associated with a modest increase in risk of residual albuminuria. TWEETABLE ABSTRACT: Pregnancy prolongation in pre-eclampsia has only a limited effect on postpartum maternal cardiovascular function

Dynamic Limits on Planar Libration-Orbit Coupling Around an Oblate Primary

This paper explores the dynamic properties of the planar system of an ellipsoidal satellite in an equatorial orbit about an oblate primary. In particular, we investigate the conditions for which the satellite is bound in librational motion or when the satellite will circulate with respect to the primary. We find the existence of stable equilibrium points about which the satellite can librate, and explore both the linearized and non-linear dynamics around these points. Absolute bounds are placed on the phase space of the libration-orbit coupling through the use of zero-velocity curves that exist in the system. These zero-velocity curves are used to derive a sufficient condition for when the satellite's libration is bound to less than 90 degrees. When this condition is not satisfied so that circulation of the satellite is possible, the initial conditions at zero libration angle are determined which lead to circulation of the satellite. Exact analytical conditions for circulation and the maximum libration angle are derived for the case of a small satellite in orbits of any eccentricity.Comment: Submitted to Celestial Mechanics and Dynamical Astronom

Volunteering in the care of people with severe mental illness: a systematic review

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Normal levels of p27Xic1 are necessary for somite segmentation and determining pronephric organ size

The Xenopus laevis cyclin dependent kinase inhibitor p27Xic1 has been shown to be involved in exit from the cell cycle and differentiation of cells into a quiescent state in the nervous system, muscle tissue, heart and retina. We show that p27Xic1 is expressed in the developing kidney in the nephrostomal regions. Using over-expression and morpholino oligonucleotide (MO) knock-down approaches we show normal levels of p27Xic1 regulate pronephros organ size by regulating cell cycle exit. Knock-down of p27Xic1 expression using a MO prevented myogenesis, as previously reported; an effect that subsequently inhibits pronephrogenesis. Furthermore, we show that normal levels of p27Xic1 are required for somite segmentation also through its cell cycle control function. Finally, we provide evidence to suggest correct paraxial mesoderm segmentation is not necessary for pronephric induction in the intermediate mesoderm. These results indicate novel developmental roles for p27Xic1, and reveal its differentiation function is not universally utilised in all developing tissues

How many is enough? Determining optimal count totals for ecological and palaeoecological studies of testate amoebae

Testate amoebae are increasingly used in ecological and palaeoecological studies of wetlands. To characterise the amoeba community a certain number of individuals need to be counted under the microscope. To date, most studies have aimed for 150 individuals, but that sample size is not based on adequate evidence. When testate amoeba concentrations are low, it can be difficult or impossible to reach this total. The impacts of lower count totals have never been seriously scrutinised. We investigated the impact of count size on number of taxa identified, quantitative inferences of environmental variables and the strength of the links between amoebae and environmental data in the context of predicting depth to water table. Low counts were simulated by random selection of individuals from four existing datasets. Results show progressively diminishing returns by all criteria as count size increases from low numbers to counts of 150. A higher count is required to identify all taxa than to adequately characterise the community for transfer function inference. We suggest that in most cases, it will be a more efficient use of time to count a greater number of samples to a lower count. While a count of 50 individuals may be sufficient for some samples from some sites we recommend that counts of 100 individuals should be sufficient for most samples. Counts need only be increased to 150 or more where the aim is to identify relatively minor, but still potentially ecologically relevant community changes. This approach will help reduce lack of replication and low resolution, which are common limitations in testate amoeba-based palaeoecological and ecological studies