1,416 research outputs found

    Ecological and temperature controls on Mg/Ca ratios of Globigerina bulloides from the southwest Pacific Ocean

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    We present Mg/Ca data for Globigerina bulloides from 10 core top sites in the southwest Pacific Ocean analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Mg/Ca values in G. bulloides correlate with observed ocean temperatures (7 degrees C-19 degrees C), and when combined with previously published data, an integrated Mg/Ca-temperature calibration for 7 degrees C-31 degrees C is derived where Mg/Ca (mmol/mol) = 0.955 x e(0.068 x T) (r(2) = 0.95). Significant variability of Mg/Ca values (20%-30%) was found for the four visible chambers of G. bulloides, with the final chamber consistently recording the lowest Mg/Ca and is interpreted, in part, to reflect changes in the depth habitat with ontogeny. Incipient and variable dissolution of the thin and fragile final chamber, and outermost layer concomitantly added to all chambers, caused by different cleaning techniques prior to solution-based ICPMS analyses, may explain the minor differences in previously published Mg/Ca-temperature calibrations for this species. If the lower Mg/Ca of the final chamber reflects changes in depth habitat, then LA-ICPMS of the penultimate (or older) chambers will most sensitively record past changes in near-surface ocean temperatures. Mean size-normalized G. bulloides test weights correlate negatively with ocean temperature (T = 31.8 x e(-30.5xwtN); r(2) = 0.90), suggesting that in the southwest Pacific Ocean, temperature is a prominent control on shell weight in addition to carbonate ion levels

    What Is the Best Way to Identify Malignant Transformation Within Pancreatic IPMN: A Systematic Review and Meta-Analyses

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    OBJECTIVES: Pancreatic intraductal papillary mucinous neoplasias (IPMNs) represent 25% of all cystic neoplasms and are precursor lesions for pancreatic ductal adenocarcinoma. This study aims to identify the best imaging modality for detecting malignant transformation in IPMN, the sensitivity and specificity of risk features on imaging, and the usefulness of tumor markers in serum and cyst fluid to predict malignancy in IPMN. METHODS: Databases were searched from November 2006 to March 2014. Pooled sensitivity and specificity of diagnostic techniques/imaging features of suspected malignancy in IPMN using a hierarchical summary receiver operator characteristic (HSROC) approach were performed. RESULTS: A total of 467 eligible studies were identified, of which 51 studies met the inclusion criteria and 37 of these were incorporated into meta-analyses. The pooled sensitivity and specificity for risk features predictive of malignancy on computed tomography/magnetic resonance imaging were 0.809 and 0.762 respectively, and on positron emission tomography were 0.968 and 0.911. Mural nodule, cyst size, and main pancreatic duct dilation found on imaging had pooled sensitivity for prediction of malignancy of 0.690, 0.682, and 0.614, respectively, and specificity of 0.798, 0.574, and 0.687. Raised serum carbohydrate antigen 19-9 (CA19-9) levels yielded sensitivity of 0.380 and specificity of 0903. Combining parameters yielded a sensitivity of 0.743 and specificity of 0.906. CONCLUSIONS: PET holds the most promise in identifying malignant transformation within an IPMN. Combining parameters increases sensitivity and specificity; the presence of mural nodule on imaging was the most sensitive whereas raised serum CA19-9 (>37 KU/l) was the most specific feature predictive of malignancy in IPMNs

    Cosmology of intersecting brane world models in Gauss-Bonnet gravity

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    We study the cosmological properties of a codimension two brane world that sits at the intersection between two four branes, in the framework of six dimensional Einstein-Gauss-Bonnet gravity. Due to contributions of the Gauss-Bonnet terms, the junction conditions require the presence of localized energy density on the codimension two defect. The induced metric on this surface assumes a FRW form, with a scale factor associated to the position of the brane in the background; we can embed on the codimension two defect the preferred form of energy density. We present the cosmological evolution equations for the three brane, showing that, for the case of pure AdS6_6 backgrounds, they acquire the same form of the ones for the Randall-Sundrum II model. When the background is different from pure AdS6_6, the cosmological behavior is potentially modified in respect to the typical one of codimension one brane worlds. We discuss, in a particular model embedded in an AdS6_6 black hole, the conditions one should satisfy in order to obtain standard cosmology at late epochs.Comment: 19 pages, no figures, JHEP style. v2: Typos corrected and references adde

    The Durham Drug Diversion Scheme

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    Origami World

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    We paste together patches of AdS6AdS_6 to find solutions which describe two 4-branes intersecting on a 3-brane with non-zero tension. We construct explicitly brane arrays with Minkowski, de Sitter and Anti-de Sitter geometries intrinsic to the 3-brane, and describe how to generalize these solutions to the case of AdS4+nAdS_{4+n}, n>2n>2, where nn n+2n+2-branes intersect on a 3-brane. The Minkowski and de Sitter solutions localize gravity to the intersection, leading to 4D Newtonian gravity at large distances. We show this explicitly in the case of Minkowski origami by finding the zero-mode graviton, and computing the couplings of the bulk gravitons to the matter on the intersection. In de Sitter case, this follows from the finiteness of the bulk volume. The effective 4D Planck scale depends on the square of the fundamental 6D Planck scale, the AdS6AdS_6 radius and the angles between the 4-branes and the radial AdSAdS direction, and for the Minkowski origami it is M42=2/3(tanα1+tanα2)M4L2M_4{}^2 = {2/3} \Bigl(\tan \alpha_1 + \tan \alpha_2 \Bigr) M_*{}^4 L^2. If Mfew×TeVM_* \sim {\rm few} \times TeV this may account for the Planck-electroweak hierarchy even if L104mL \sim 10^{-4} {\rm m}, with a possibility for sub-millimeter corrections to the Newton's law. We comment on the early universe cosmology of such models.Comment: plain LaTeX, 23 pages + 2 .eps figure

    Intervention planning and modification of the BUMP intervention: a digital intervention for the early detection of raised blood pressure in pregnancy

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    Background: Hypertensive disorders in pregnancy, particularly pre-eclampsia, pose a substantial health risk for both maternal and foetal outcomes. The BUMP (Blood Pressure Self-Monitoring in Pregnancy) interventions are being tested in a trial. They aim to facilitate the early detection of raised blood pressure through self-monitoring. This article outlines how the self-monitoring interventions in the BUMP trial were developed and modified using the person-based approach to promote engagement and adherence. Methods: Key behavioural challenges associated with blood pressure self-monitoring in pregnancy were identified through synthesising qualitative pilot data and existing evidence, which informed guiding principles for the development process. Social cognitive theory was identified as an appropriate theoretical framework. A testable logic model was developed to illustrate the hypothesised processes of change associated with the intervention. Iterative qualitative feedback from women and staff informed modifications to the participant materials. Results: The evidence synthesis suggested women face challenges integrating self-monitoring into their lives and that adherence is challenging at certain time points in pregnancy (for example, starting maternity leave). Intervention modification included strategies to address adherence but also focussed on modifying outcome expectancies, by providing messages explaining pre-eclampsia and outlining the potential benefits of self-monitoring. Conclusions: With an in-depth understanding of the target population, several methods and approaches to plan and develop interventions specifically relevant to pregnant women were successfully integrated, to address barriers to behaviour change while ensuring they are easy to engage with, persuasive and acceptable

    Supersymmetric Large Extra Dimensions and the Cosmological Constant Problem

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    This article briefly summarizes and reviews the motivations for - and the present status of - the proposal that the small size of the observed Dark Energy density can be understood in terms of the dynamical relaxation of two large extra dimensions within a supersymmetric higher-dimensional theory.Comment: Talk presented to Theory Canada I, Vancouver, June 2005. References added in V

    Top research priorities in healthcare-associated infection in the UK

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    Background: There is a mismatch between research questions which are considered to be important by patients, carers and healthcare professionals and the research performed in many fields of medicine. No relevant studies which have assessed research priorities in healthcare-associated infection (HCAI) that have involved patients' and carers' opinions were identified in the literature. / Aim: The Healthcare-Associated Infections Priority Setting Partnership was established to identify the top research priorities in the prevention, diagnosis and treatment of HCAI in the UK, considering the opinions of all these groups. / Methods: The methods broadly followed the principles of the James Lind Alliance (JLA) priority setting activity. / Findings: In total, 259 unique valid research questions were identified from 221 valid responses to a consultation of patients, carers and healthcare professionals after seeking their opinions for research priorities. The steering committee of the priority setting partnership rationalized these to 50 unique questions. A literature review established that for these questions there were no recent high-quality systematic reviews, high-quality systematic reviews which concluded that further studies were necessary, or the steering committee considered that further research was required despite the conclusions of recent systematic reviews. An interim survey ranked the 50 questions, and the 10 main research priorities were identified from the top 32 questions by consensus at a final priority setting workshop of patients, carers and healthcare professionals using group discussions. / Conclusions: A priority setting process using JLA methods and principles involving patients, carers and healthcare professionals was used to identify the top 10 priority areas for research related to HCAI. Basic, translational, clinical and public health research would be required to address these uncertainties

    Assembly of infectious enteroviruses depends on multiple, conserved genomic RNA-coat protein contacts.

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    Picornaviruses are important viral pathogens, but despite extensive study, the assembly process of their infectious virions is still incompletely understood, preventing the development of anti-viral strategies targeting this essential part of the life cycle. We report the identification, via RNA SELEX and bioinformatics, of multiple RNA sites across the genome of a typical enterovirus, enterovirus-E (EV-E), that each have affinity for the cognate viral capsid protein (CP) capsomer. Many of these sites are evolutionarily conserved across known EV-E variants, suggesting they play essential functional roles. Cryo-electron microscopy was used to reconstruct the EV-E particle at ~2.2 Å resolution, revealing extensive density for the genomic RNA. Relaxing the imposed symmetry within the reconstructed particles reveals multiple RNA-CP contacts, a first for any picornavirus. Conservative mutagenesis of the individual RNA-contacting amino acid side chains in EV-E, many of which are conserved across the enterovirus family including poliovirus, is lethal but does not interfere with replication or translation. Anti-EV-E and anti-poliovirus aptamers share sequence similarities with sites distributed across the poliovirus genome. These data are consistent with the hypothesis that these RNA-CP contacts are RNA Packaging Signals (PSs) that play vital roles in assembly and suggest that the RNA PSs are evolutionarily conserved between pathogens within the family, augmenting the current protein-only assembly paradigm for this family of viruses
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