1,676 research outputs found

    Pencil grasp comparisons among Hispanic and Anglo-American preschoolers, ages three to five

    Get PDF
    The purpose of this study was to examine and determine patterns of pencil grasp in Hispanic, African-American, and Anglo-American preschoolers ages three to five, and to examine if parental influence is associated with these patterns. [This is an excerpt from the abstract. For the complete abstract, please see the document.

    The Microbial Community of a Terrestrial Anoxic Inter-Tidal Zone: A Model for Laboratory-Based Studies of Potentially Habitable Ancient Lacustrine Systems on Mars

    Get PDF
    Evidence indicates that Gale crater on Mars harboured a fluvio-lacustrine environment that was subjected to physio-chemical variations such as changes in redox conditions and evaporation with salinity changes, over time. Microbial communities from terrestrial environmental analogues sites are important for studying such potential habitability environments on early Mars, especially in laboratory-based simulation experiments. Traditionally, such studies have predominantly focused on microorganisms from extreme terrestrial environments. These are applicable to a range of Martian environments; however, they lack relevance to the lacustrine systems. In this study, we characterise an anoxic inter-tidal zone as a terrestrial analogue for the Gale crater lake system according to its chemical and physical properties, and its microbiological community. The sub-surface inter-tidal environment of the River Dee estuary, United Kingdom (53°21'015.40" N, 3°10'024.95" W) was selected and compared with available data from Early Hesperian-time Gale crater, and temperature, redox, and pH were similar. Compared to subsurface ‘groundwater’-type fluids invoked for the Gale subsurface, salinity was higher at the River Dee site, which are more comparable to increases in salinity that likely occurred as the Gale crater lake evolved. Similarities in clay abundance indicated similar access to, specifically, the bio-essential elements Mg, Fe and K. The River Dee microbial community consisted of taxa that were known to have members that could utilise chemolithoautotrophic and chemoorganoheterotrophic metabolism and such a mixed metabolic capability would potentially have been feasible on Mars. Microorganisms isolated from the site were able to grow under environment conditions that, based on mineralogical data, were similar to that of the Gale crater’s aqueous environment at Yellowknife Bay. Thus, the results from this study suggest that the microbial community from an anoxic inter-tidal zone is a plausible terrestrial analogue for studying habitability of fluvio-lacustrine systems on early Mars, using laboratory-based simulation experiments

    Evolutionary conservation and divergence of the transcriptional regulation of bivalve shell secretion across life history stages

    Get PDF
    Acknowledgements and Funding Information We are grateful to Andrew Gillis for use for paraffin histology and microscopy equipment and enthusiastic support of this work and the Rothera marine team for collecting the adult Laternula elliptica broodstock. This work was supported by UKRI Natural Environment Research Council (NERC) Core Funding to the British Antarctic Survey, a DTG Studentship (Project Reference: NE/J500173/1) and a Junior Research Fellowship to V.A.S. from Wolfson College, University of Cambridge. Review History: https://www.webofscience.com/api/gateway/wos/peer-review/10.1098/rsos.221022/Peer reviewedPublisher PD

    Outer organic layer and internal repair mechanism protects pteropod Limacina helicina from ocean acidification

    Get PDF
    Scarred shells of polar pteropod Limacina helicina collected from the Greenland Sea in June 2012 reveal a history of damage, most likely failed predation, in earlier life stages. Evidence of shell fracture and subsequent re-growth is commonly observed in specimens recovered from the sub-Arctic and further afield. However, at one site within sea–ice on the Greenland shelf, shells that had been subject to mechanical damage were also found to exhibit considerable dissolution. It was evident that shell dissolution was localised to areas where the organic, periostracal sheet that covers the outer shell had been damaged at some earlier stage during the animal’s life. Where the periostracum remained intact, the shell appeared pristine with no sign of dissolution. Specimens which appeared to be pristine following collection were incubated for four days. Scarring of shells that received periostracal damage during collection only became evident in specimens that were incubated in waters undersaturated with respect to aragonite, ΩAr≀1. While the waters from which the damaged specimens were collected at the Greenland Sea sea–ice margin were not ΩAr≀1, the water column did exhibit the lowest ΩAr values observed in the Greenland and Barents Seas, and was likely to have approached ΩAr≀1 during the winter months. We demonstrate that L. helicina shells are only susceptible to dissolution where both the periostracum has been breached and the aragonite beneath the breach is exposed to waters of ΩAr≀1. Exposure of multiple layers of aragonite in areas of deep dissolution indicate that, as with many molluscs, L. helicina is able to patch up dissolution damage to the shell by secreting additional aragonite internally and maintain their shell. We conclude that, unless breached, the periostracum provides an effective shield for pteropod shells against dissolution in waters ΩAr≀1, and when dissolution does occur the animal has an effective means of self-repair. We suggest that future studies of pteropod shell condition are undertaken on specimens from which the periostracum has not been removed in preparation

    Failure to up-regulate VEGF165b in maternal plasma is a first trimester predictive marker for pre-eclampsia

    Get PDF
    Pre-eclampsia is a pregnancy-related condition characterized by hypertension, proteinuria and endothelial dysfunction. VEGF165b, formed by alternative splicing of VEGF (vascular endothelial growth factor) pre-mRNA, inhibits VEGF165-mediated vasodilation and angiogenesis, but has not been quantified in pregnancy. ELISAs were used to measure means±S.E.M. plasma VEGF165b, sEng (soluble endoglin) and sFlt-1 (soluble fms-like tyrosine kinase-1). At 12 weeks of gestation, the plasma VEGF165b concentration was significantly up-regulated in plasma from women who maintained normal blood pressure throughout their pregnancy (normotensive group, 4.90±1.6 ng/ml; P<0.01, as determined using a Mann-Whitney U test) compared with non-pregnant women (0.40±0.22 ng/ml). In contrast, in patients who later developed pre-eclampsia, VEGF165b levels were lower than in the normotensive group (0.467±0.209 ng/ml), but were no greater than non-pregnant women. At term, plasma VEGF165b concentrations were greater than normal in both pre-eclamptic (3.75±2.24 ng/ml) and normotensive (10.58 ng/ml±3.74 ng/ml; P>0.1 compared with pre-eclampsia) pregnancies. Patients with a lower than median plasma VEGF165b at 12 weeks had elevated sFlt-1 and sEng pre-delivery. Concentrations of sFlt-1 (1.20±0.07 and 1.27±0.18 ng/ml) and sEng (4.4±0.18 and 4.1±0.5 ng/ml) were similar at 12 weeks of gestation in the normotensive and pre-eclamptic groups respectively. Plasma VEGF165b levels were elevated in pregnancy, but this increase is delayed in women that subsequently develop pre-eclampsia. In conclusion, low VEGF165b may therefore be a clinically useful first trimester plasma marker for increased risk of pre-eclampsia

    Pteropods counter mechanical damage and dissolution through extensive shell repair

    Get PDF
    The dissolution of the delicate shells of sea butterflies, or pteropods, has epitomised discussions regarding ecosystem vulnerability to ocean acidification over the last decade. However, a recent demonstration that the organic coating of the shell, the periostracum, is effective in inhibiting dissolution suggests that pteropod shells may not be as susceptible to ocean acidification as previously thought. Here we use micro-CT technology to show how, despite losing the entire thickness of the original shell in localised areas, specimens of polar species Limacina helicina maintain shell integrity by thickening the inner shell wall. One specimen collected within Fram Strait with a history of mechanical and dissolution damage generated four times the thickness of the original shell in repair material. The ability of pteropods to repair and maintain their shells, despite progressive loss, demonstrates a further resilience of these organisms to ocean acidification but at a likely metabolic cost

    Acute gastrointestinal illness in two Inuit communities : burden of illness in Rigolet and Iqaluit, Canada : author version

    Get PDF
    Results of this study highlight the need for systematic data collection to better understand and support previously anecdotal indications of high acute gastrointestinal illness (AGI) incidence. Cross-sectional retrospective surveys captured information on AGI and potential environmental risk factors. Lack of access to health services can result in reduced care-seeking behaviour, which can compromise the quality and quantity of available surveillance data. The aim of the research was to estimate the incidence and prevalence of AGI, and to identify potential socio-economic and environmental risk factors in the Inuit communities of Rigolet, Nunatsiavut and Iqaluit in Nunavut, Canada
    • 

    corecore