3,185 research outputs found

    An early Anglo-Saxon bridle-fitting from South Leckaway, Forfar, Angus, Scotland

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    [FIRST PARAGRAPH] In February 2003 the Kinnettles Heritage Group made a quite unexpected find during field-walking at South Leckaway farm near Forfar, Angus (NGR NO 4379 4810): the most northerly example in Britain — by about 150 miles — of an Anglo- Saxon object decorated in Salin’s Style I. It lay isolated and face down on the surface. A follow-up field-walk at the end of the month confirmed, partly with the aid of a metal detector, that there were no readily apparent additional pieces of metalwork, associated structures or burial evidence. The find was reported under the Scottish Treasure Trove legislation, duly claimed and allocated in June 2003 to the Meffan Institute, Forfar (part of Angus Cultural Services)

    The early medieval origin of Perth, Scotland

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    The radiocarbon results (and Bayesian modeling) of 15 samples of carbonized food residues removed from the external surface of rim sherds of cooking pots indicate that shellyware pottery first appeared in Perth, Scotland, around cal AD 9101020 (95% probability) and that it had disappeared by cal AD 10201140 (95% probability). Previously, it had been suggested that this pottery could not date to before AD 1150. These data, together with 14C analyses carried out on leather artifacts and a sample of wattle from a ditch lining, also demonstrate that there was occupation in Perth about 100 yr or more prior to the granting of royal burgh status to Perth in the 1120s

    Sigmoid Neural Transfer Function Realised by Percolation

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    An experiment using the phenomenon of percolation has been conducted to demonstrate the implementation of neural functionality (summing and sigmoid transfer). A simple analog approximation to digital percolation is implemented. The device consists of a piece of amorphous silicon with stochastic bit-stream optical inputs, in which a current percolating from one end to the other defines the neuron output, also in the form of a stochastic bit stream. Preliminary experimental results are presented

    Tectonometamorphic evolution of Seram and Ambon, eastern Indonesia:Insights from ⁎⁰Ar/ÂłâčAr geochronology

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    The island of Seram, eastern Indonesia, experienced a complex Neogene history of multiple metamorphic and deformational events driven by Australia–SE Asia collision. Geological mapping, and structural and petrographic analysis has identified two main phases in the island's tectonic, metamorphic, and magmatic evolution: (1) an initial episode of extreme extension that exhumed hot lherzolites from the subcontinental lithospheric mantle and drove ultrahigh-temperature metamorphism and melting of adjacent continental crust; and (2) subsequent episodes of extensional detachment faulting and strike-slip faulting that further exhumed granulites and mantle rocks across Seram and Ambon. Here we present the results of sixteen 40Ar/39Ar furnace step heating experiments on white mica, biotite, and phlogopite for a suite of twelve rocks that were targeted to further unravel Seram's tectonic and metamorphic history. Despite a wide lithological and structural diversity among the samples, there is a remarkable degree of correlation between the 40Ar/39Ar ages recorded by different rock types situated in different structural settings, recording thermal events at 16 Ma, 5.7 Ma, 4.5 Ma, and 3.4 Ma. These frequently measured ages are defined, in most instances, by two or more 40Ar/39Ar ages that are identical within error. At 16 Ma, a major kyanite-grade metamorphic event affected the Tehoru Formation across western and central Seram, coincident with ultrahigh-temperature metamorphism and melting of granulite-facies rocks comprising the Kobipoto Complex, and the intrusion of lamprophyres. Later, at 5.7 Ma, Kobipoto Complex rocks were exhumed beneath extensional detachment faults on the Kaibobo Peninsula of western Seram, heating and shearing adjacent Tehoru Formation schists to form Taunusa Complex gneisses. Then, at 4.5 Ma, 40Ar/39Ar ages record deformation within the Kawa Shear Zone (central Seram) and overprinting of detachment faults in western Seram. Finally, at 3.4 Ma, Kobipoto Complex migmatites were exhumed on Ambon, at the same time as deformation within the Kawa Shear Zone and further overprinting of detachments in western Seram. These ages support there having been multiple synchronised episodes of high-temperature extension and strike-slip faulting, interpreted to be the result of Western Seram having been ripped off from SE Sulawesi, extended, and dragged east by subduction rollback of the Banda Slab

    Variable plasmid fitness effects and mobile genetic element dynamics across Pseudomonas species

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    Mobile genetic elements (MGE) such as plasmids and transposons mobilise genes within and between species, playing a crucial role in bacterial evolution via horizontal gene transfer (HGT). Currently we lack data on variation in MGE dynamics across bacterial host species. We tracked the dynamics of a large conjugative plasmid, pQBR103, and its Tn5042 mercury resistance transposon, in five diverse Pseudomonas species in environments with and without mercury selection. Plasmid fitness effects and stability varied extensively between host species and environments, as did the propensity for chromosomal capture of the Tn5042 mercury resistance transposon associated with loss of the plasmid. Whereas P. fluorescens and P. savastanoi stably maintained the plasmid in both environments, the plasmid was highly unstable in P. aeruginosa and P. putida, where plasmid-free genotypes with Tn5042 captured to the chromosome invaded to higher frequency under mercury selection. These data confirm that plasmid stability is dependent upon the specific genetic interaction of the plasmid and host chromosome rather than being a property of plasmids alone, and moreover imply that MGE dynamics in diverse natural communities are likely to be complex and driven by a subset of species capable of stably maintaining plasmids which would then act as hubs of HGT

    Directed differentiation of porcine epiblast-derived neural progenitor cells into neurons and glia

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    AbstractNeural progenitor cells (NPCs) are promising candidates for cell-based therapy of neurodegenerative diseases; however, safety concerns must be addressed through transplantation studies in large animal models, such as the pig. The aim of this study was to derive NPCs from porcine blastocysts and evaluate their in-vitro differentiation potential. Epiblasts were manually isolated from expanded hatched blastocysts and cultured on MEF feeder cells. Outgrowth colonies were passaged to MS5 cells and rosettes were further passaged to Matrigel-coated dishes containing bFGF and EGF. Three NPC lines were established which showed expression of SOX2, NESTIN and VIMENTIN. One line was characterised in more detail, retaining a normal karyotype and proliferating for more than three months in culture. Following differentiation, TUJI was significantly up-regulated in protocol 2 (RA and SHH; 58% positive cells) as were NF and TH. In contrast, MBP was significantly up-regulated in protocol 3 (FGF8 and SHH; 63% positive cells), whereas, GFAP was significantly up-regulated in protocols 1–4 (33%, 25%, 43% and 22%). The present study provides the first report of a porcine blastocyst-derived NPC line capable of differentiating into both neurons and glia, which may be of paramount importance for future transplantation studies in large animal models of neurodegenerative diseases

    Weight-related quality of life in obese, pregnant women in South Africa

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    Objective: The global obesity pandemic includes pregnant women. Obesity may negatively impact quality of life (QOL). A validated, obesity-specific, QOL  assessment tool was used to assess the impact of obesity on five specific domains.Methods: A prospective cohort study was performed at Tygerberg Academic Hospital in South Africa. Morbid obesity was defined as a body mass index (BMI) of 40–49.9 kg/m2 and super-obesity as BMI > 50 kg/m2, using the first recorded weight during the pregnancy. Pregnant women with a BMI ≄ 40 were approached in the high-risk antenatal clinic where written informed consent was taken before  recruitment. Using the QOL tool they answered statements about their current  experiences.Results: A total of 66 morbidly obese and 46 super-obese women were enrolled  across an age range of 18–45 years. Physical function and self-esteem were the domains with the lowest QOL scores. When comparing morbid with super obesity, all scores were significantly lower in the latter group except for the domains of  self-esteem and sexual life.Conclusion: Morbid and super-obesity occur across the full spectrum of the adult reproductive period. Physical function and self-esteem are most affected while QOL is linked to the degree of obesity.Keywords: obesity, pregnancy, quality of life, morbid obesity, super-obesity

    North Atlantic millennial-scale climate variability 910 to 790 ka and the role of the equatorial insolation forcing

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    The Mid-Pleistocene transition (MPT) was the time when quasi-periodic (not, vert, similar 100 kyr), high-amplitude glacial variability developed in the absence of any significant change in the character of orbital forcing, leading to the establishment of the characteristic pattern of late Pleistocene climate variability. It has long been known that the interval around 900 ka stands out as a critical point of the MPT, when major glaciations started occurring most notably in the northern hemisphere. Here we examine the record of climatic conditions during this significant interval, using high-resolution stable isotope records from benthic and planktonic foraminifera from a sediment core in the North Atlantic (Integrated Ocean Drilling Program Expedition 306, Site U1313). We have considered the time interval from late in Marine Isotope Stage (MIS) 23 to MIS 20 (910 to 790 ka). Our data indicate that interglacial MIS 21 was a climatically unstable period and was broken into four interstadial periods, which have been identified and correlated across the North Atlantic region. These extra peaks tend to contradict previous studies that interpreted the MIS 21 variability as consisting essentially of a linear response to cyclical changes in orbital parameters. Cooling events in the surface record during MIS 21 were associated with low benthic carbon isotope excursions, suggesting a coupling between surface temperature changes and the strength of the Atlantic meridional overturning circulation. Time series analysis performed on the whole interval indicates that benthic and planktonic oxygen isotopes have significant concentrations of spectral power centered on periods of 10.7 kyr and 6 kyr, which is in agreement with the second and forth harmonic of precession. The excellent correspondence between the foraminifera ÎŽ18O records and insolation variations at the Equator in March and September suggests that a mechanism related to low-latitude precession variations, advected to the high latitudes by tropical convective processes, might have generated such a response. This scenario accounts for the presence of oscillations at frequencies equal to precession harmonics at Site U1313, as well as the occurrence of higher amplitude oscillations between the MIS22/21 transition and most of MIS 21, times of enhanced insolation variability

    Involution of the mouse mammary gland is associated with an immune cascade and an acute-phase response, involving LBP, CD14 and STAT3

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    INTRODUCTION: Involution of the mammary gland is a complex process of controlled apoptosis and tissue remodelling. The aim of the project was to identify genes that are specifically involved in this process. METHODS: We used Affymetrix oligonucleotide microarrays to perform a detailed transcript analysis on the mechanism of controlled involution after withdrawal of the pups at day seven of lactation. Some of the results were confirmed by semi-quantitative reverse transcriptase polymerase chain reaction, Western blotting or immunohistochemistry. RESULTS: We identified 145 genes that were specifically upregulated during the first 4 days of involution; of these, 49 encoded immunoglobulin genes. A further 12 genes, including those encoding the signal transducer and activator of transcription 3 (STAT3), the lipopolysaccharide receptor (CD14) and lipopolysaccharide-binding protein (LBP), were involved in the acute-phase response, demonstrating that the expression of acute-phase response genes can occur in the mammary gland itself and not only in the liver. Expression of LBP and CD14 was upregulated, at both the RNA and protein level, immediately after pup withdrawal; CD14 was strongly expressed in the luminal epithelial cells. Other genes identified suggested neutrophil activation early in involution, followed by macrophage activation late in the process. Immunohistochemistry and histological staining confirmed the infiltration of the involuting mammary tissue with neutrophils, plasma cells, macrophages and eosinophils. CONCLUSION: Oligonucleotide microarrays are a useful tool for identifying genes that are involved in the complex developmental process of mammary gland involution. The genes identified are consistent with an immune cascade, with an early acute-phase response that occurs in the mammary gland itself and resembles a wound healing process
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