775 research outputs found

    Effect of Sm-, Gd- codoping on structural modifications in aluminoborosilicate glasses under beta-irradiation

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    Two series of Sm-, Gd-codoped aluminoborosilicate glasses with different total rare earth content have been studied in order to examine the codoping effect on the structural modifications of beta-irradiated glasses. The data obtained by Electron Paramagnetic Resonance spectroscopy indicated that relative amount of Gd3+ ions located in network former position reveals non-linear dependence on Sm/Gd ratio. Besides, codoping leads to the evolution of the EPR signal attributed to defects created by irradiation: superhyperfine structure of boron oxygen hole centres EPR line becomes less noticeable and resolved with increase of Gd amount. This fact manifests that Gd3+ ions are mainly diluted in vicinity of the boron network. By Raman spectroscopy, we showed that the structural changes induced by the irradiation also reveal non-linear behaviour with Sm/Gd ratio. In fact, the shift of the Si-O-Si bending vibration modes has a clear minimum for the samples containing equal amount of Sm and Gd (50:50) in both series of the investigated glasses. In contrast, for single doped glass there is no influence of dopant's content on Si-O-Si shift (in case of Gd) or its diminution (in case of Sm) occurs which is explained by the reduction process influence. At the same time, no noticeable effect of codoping on Sm3+ intensity as well as on Sm2+ emission or on Sm reduction process was observed

    The UK DNA banking network: a “fair access” biobank

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    The UK DNA Banking Network (UDBN) is a secondary biobank: it aggregates and manages resources (samples and data) originated by others. The network comprises, on the one hand, investigator groups led by clinicians each with a distinct disease specialism and, on the other hand, a research infrastructure to manage samples and data. The infrastructure addresses the problem of providing secure quality-assured accrual, storage, replenishment and distribution capacities for samples and of facilitating access to DNA aliquots and data for new peer-reviewed studies in genetic epidemiology. ‘Fair access’ principles and practices have been pragmatically developed that, unlike open access policies in this area, are not cumbersome but, rather, are fit for the purpose of expediting new study designs and their implementation. UDBN has so far distributed >60,000 samples for major genotyping studies yielding >10 billion genotypes. It provides a working model that can inform progress in biobanking nationally, across Europe and internationally

    Efficient Computation of Casimir Interactions between Arbitrary 3D Objects

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    We introduce an efficient technique for computing Casimir energies and forces between objects of arbitrarily complex 3D geometries. In contrast to other recently developed methods, our technique easily handles non-spheroidal, non-axisymmetric objects and objects with sharp corners. Using our new technique, we obtain the first predictions of Casimir interactions in a number of experimentally relevant geometries, including crossed cylinders and tetrahedral nanoparticles.Comment: 4 pages, 4 figure

    Exploring the performance of the spectrometer prisma in heavy zirconium and xenon mass regions

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    We present results from two recent runs which illustrate the performance of the PRISMA spectrometer in the proximity of the upper limit of its operational interval, namely 96Zr + 124Sn at Elab = 500 MeV and 136Xe + 208Pb at Elab = 930 MeV. In the latter run, the Îł array CLARA also allowed us to identify previously unknown Îł transitions in the nuclides 136Cs and 134I

    Thresholds : Gesture, idea and action in the Performance Art of Andrew Drummond, Di ffrench and David Mealing

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    This thesis examines the work of three New Zealand artists who engaged with processes of performance art during the 1970s and 1980s. David Mealing, Andrew Drummond and Di ffrench integrated performance gestures that mutated into object or conceptual based practices in the 1980s and 1990s. An analysis of their work reveals both similarities and differences, all adjacent to corporeal, political and aesthetic issues and ideas that stem from international and national events particular to the milieu in which they worked. The three artists stand apart from their contemporaries due to their focussed positions as socio-political commentators during a turbulent time in New Zealand history. A large body of written and oral research on their work provides an historical view of the period from 1969 - 1999 that will focus specifically on their aesthetic experimentation and concerns with the fragmentation of the body, self and identity, and, importantly, their intended use of art to effect change. Performance art in New Zealand underwent a burst of energy from 1969 as time-based activity offered an alternative to the static painterly or totemic art practices, as found in much international late modernism. Mealing, Drummond and ffrench explored a notion of performance art that resided in and beyond the margins of mainstream activity. A concept of the limen or the margin, the threshold and the littoral zone - a metaphorical place of creativity is applied to this analysis of their work. These individuals expressed through ritual and symbol found in notions of the-limen, socio-political beliefs that reflected a view of artistic responsibility toward pressing issues of identity, freedom of expression, ecological wellbeing and the human condition. Each artist concentrated on phenomenological themes surrounding the body, explored alternative sculptural material and enjoyed instances of imaginative communication. The body trace that evolved from the temporal moment, their relationship to the land and the urban environment, and an intersubjective exchange with the audience were all engaged with. This is articulated in their practices of socio-political interaction, as expressed through Mealing's interventions, a spatial/kinetic continuum, as seen in Drummond's sculptures, and a performative materialisation of difference as evident in the cibachromes of Di ffrench. Historical international precedents of performance art will interweave with this specific New Zealand study in order to further highlight the diversity of performance art that these artists employed in their idiosyncratic journeys along the borderlands of art making

    Partial silicification of chalk fossils from the Chilterns

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    RESP-624

    Molecular analysis of HLA-DQB1 alleles in childhood common acute lymphoblastic leukaemia.

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    Epidemiological studies suggest that childhood common acute lymphoblastic leukaemia (c-ALL) may be the rare outcome of early post-natal infection with a common infectious agent. One of the factors that may determine whether a child succumbs to c-ALL is how it responds to the candidate infection. Since immune responses to infection are under the partial control of (human leucocyte antigen) HLA genes, an association between an HLA allele and c-ALL could provide support for an infectious aetiology. To define the limit of c-ALL susceptibility within the HLA region, we have compared HLA-DQB1 allele frequencies in a cohort of 62 children with c-ALL with 76 newborn controls, using group-specific polymerase chain reaction (PCR) amplification, and single-strand conformation polymorphism (SSCP) analysis. We find that a significant excess of children with c-ALL type for DQB1*05 [relative risk (RR): 2.54, uncorrected P=0.038], and a marginal excess with DQB1*0501 (RR: 2.18; P=0.095). Only 3 of the 62 children with c-ALL have the other susceptibility allele, DPB1*0201 as well as DQB1*0501, whereas 15 had one or the other allele. This suggests that HLA-associated susceptibility may be determined independently by at least two loci, and is not due to linkage disequilibrium. The combined relative risk of the two groups of children with DPB1*0201 and/or DQB1*0501 is 2.76 (P=0.0076). Analysis of amino acids encoded by exon 2 of DQB1 reveal additional complexity, with significant (P<0.05) or borderline-significant increases in Gly26, His30, Val57, Glu66-Val67 encoding motifs in c-ALL compared with controls. Since these amino acids are not restricted to DQB1*0501, our results suggest that, as with DPB1, the increased risk of c-ALL associated with DQB1 is determined by specific amino acid encoding motifs rather than by an individual allele. These results also suggest that HLA-associated susceptibility to c-ALL may not be restricted to the region bounded by DPB1 and DQB1

    Dogslife: A web-based longitudinal study of Labrador Retriever health in the UK

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    <p>Abstract</p> <p>Background</p> <p>Dogslife is the first large-scale internet-based longitudinal study of canine health. The study has been designed to examine how environmental and genetic factors influence the health and development of a birth cohort of UK-based pedigree Labrador Retrievers.</p> <p>Results</p> <p>In the first 12 months of the study 1,407 Kennel Club (KC) registered eligible dogs were recruited, at a mean age of 119 days of age (SD 69 days, range 3 days – 504 days). Recruitment rates varied depending upon the study team’s ability to contact owners. Where owners authorised the provision of contact details 8.4% of dogs were recruited compared to 1.3% where no direct contact was possible. The proportion of dogs recruited was higher for owners who transferred the registration of their puppy from the breeder to themselves with the KC, and for owners who were sent an e-mail or postcard requesting participation in the project. Compliance with monthly updates was highly variable. For the 280 dogs that were aged 400 days or more on the 30<sup>th</sup> June 2011, we estimated between 39% and 45% of owners were still actively involved in the project. Initial evaluation suggests that the cohort is representative of the general population of the KC registered Labrador Retrievers eligible to enrol with the project. Clinical signs of illnesses were reported in 44.3% of Labrador Retrievers registered with Dogslife (median age of first illness 138 days), although only 44.1% of these resulted in a veterinary presentation (median age 316 days).</p> <p>Conclusions</p> <p>The web-based platform has enabled the recruitment of a representative population of KC registered Labrador Retrievers, providing the first large-scale longitudinal population-based study of dog health. The use of multiple different methods (e-mail, post and telephone) of contact with dog owners was essential to maximise recruitment and retention of the cohort.</p
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