2,654 research outputs found

    On the emissions and transport of bromoform: Sensitivity to model resolution and emission location

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    Abstract. Bromoform (CHBr3) is a short-lived species with an important but poorly quantified ocean source. It can be transported to the Tropical Tropopause Layer (TTL), in part by rapid, deep convective lifting, from where it can influence the global stratospheric ozone budget. In a modelling study, we investigate the importance of the regional distribution of the emissions and of model resolution for the transport of bromoform to the TTL. We use two idealized CHBr3 emission fields (one coastal, one uniformly distributed across the oceans) implemented in high- and coarse-resolution (HR and CR) versions of the same global model and focus on February as the period of peak convection in the West Pacific. Using outgoing long-wave radiation and precipitation as metrics, the HR version of the model is found to represent convection better. In the more realistic HR model version, the coastal emission scenario leads to 15ā€“20 % more CHBr3 in the global TTL, and up to three times more CHBr3 in the TTL over the Maritime Continent, than when uniform emissions of the same tropical magnitude are employed. Using the uniform emission scenario in both model versions, the distribution of CHBr3 at 15.7 km (approximately the level of zero net radiative heating) is qualitatively consistent with the differing geographic distributions of convection. However, averaged over the whole tropics, the amount of CHBr3 in the TTL in the two model versions is similar. Using the coastal scenario, in which emissions are particularly high in the Maritime Continent because of its long coastlines, the mixing ratio of CHBr3 in the TTL is enhanced over the Maritime Continent in both model versions. The enhancement is larger, and the peak in CHBr3 mixing ratio occurs at a higher altitude, in the HR model version. Our regional-scale results indicate that using aircraft measurements and coarse global models to infer CHBr3 emissions will be very difficult, particularly if (as is possible) emissions are distributed heterogeneously and in regions of strong convective activity. In contrast, the global-scale agreement between our CR and HR calculations suggests model resolution is less vital for studies focused on the transport of bromine into the global stratosphere. This work was supported through the ERC ACCI project (project no. 267760), and by NERC through grant nos. NE/J006246/1 and NE/F1016012/1. N. R. P. Harris was supported by a NERC Advanced Research Fellowship (NE/G014655/1).This is the final version of the article. It first appeared from Copernicus Publications via http://dx.doi.org/10.5194/acp-15-14031-201

    Combined use of a femtosecond laser and a microkeratome in obtaining thin grafts for Descemet stripping automated endothelial keratoplasty: an eye bank study

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    Purpose: To evaluate the use of a femtosecond laser combined with a microkeratome in the preparation of posterior corneal disks for Descemet stripping automated endothelial keratoplasty (DSAEK).ā€©Methods: This experimental study involved ultrathin DSAEK tissue preparation of 22 donor corneas unsuitable for transplantation. The first cut was performed with an IntralaseĀ® FS60 laser and the second cut with a Moria CBm 300-Āµm microkeratome. The thickness of the first cut was modified for each cornea to obtain a final graft thickness of less than 110 Āµm. Precut and postcut central pachymetry were performed with an ultrasonic pachymeter. Central endothelial cell density (ECD) was calculated before and 24 hours after tissue preparation. ā€©Results: Final graft thickness was 105.0 Ā± 26.1 (SD) Āµm (range 65-117). The mean microkeratome head cut thickness was 324.5 Ā± 10.9 Āµm (range 310-345). Precut and postcut ECDs averaged 2250 Ā± 222 and 2093 Ā± 286 cells/mm2, respectively, representing 6.9% of cell loss. No corneas were perforated.ā€©Conclusion: Femtosecond FS60 lasers and Moria CBm 300-Āµm microkeratomes can be used sequentially to prepare consistently thin DSAEK grafts with no irregular cuts or cornea perforations

    FSL-BM: Fuzzy Supervised Learning with Binary Meta-Feature for Classification

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    This paper introduces a novel real-time Fuzzy Supervised Learning with Binary Meta-Feature (FSL-BM) for big data classification task. The study of real-time algorithms addresses several major concerns, which are namely: accuracy, memory consumption, and ability to stretch assumptions and time complexity. Attaining a fast computational model providing fuzzy logic and supervised learning is one of the main challenges in the machine learning. In this research paper, we present FSL-BM algorithm as an efficient solution of supervised learning with fuzzy logic processing using binary meta-feature representation using Hamming Distance and Hash function to relax assumptions. While many studies focused on reducing time complexity and increasing accuracy during the last decade, the novel contribution of this proposed solution comes through integration of Hamming Distance, Hash function, binary meta-features, binary classification to provide real time supervised method. Hash Tables (HT) component gives a fast access to existing indices; and therefore, the generation of new indices in a constant time complexity, which supersedes existing fuzzy supervised algorithms with better or comparable results. To summarize, the main contribution of this technique for real-time Fuzzy Supervised Learning is to represent hypothesis through binary input as meta-feature space and creating the Fuzzy Supervised Hash table to train and validate model.Comment: FICC201

    Regge behavior saves string theory from causality violations

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    Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. [1]. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters b ā‰¤ l s (the string-length parameter) with l s ā‰« R p (the characteristic scale of the D p -brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory ā€” and in particular its Regge behavior ā€” is taken into account

    Anorectal Involvement in a Patient with Multiple Myeloma

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    Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells. Symptomatic gastrointestinal involvement is uncommon. We report the case of a 45-year-old patient admitted with an anorectal polypoid lesion, which progressed to colonic obstruction. Investigation revealed a secondary plasmacytoma associated with multiple myeloma. We discuss the characteristics of this rare entity with poor prognosis, its clinical implications and treatment options.info:eu-repo/semantics/publishedVersio

    A prospective cohort study comparing the reactogenicity of trivalent influenza vaccine in pregnant and non-pregnant women

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    Background: Influenza vaccination during pregnancy can prevent serious illness in expectant mothers and provide protection to newborns; however, historically uptake has been limited due to a number of factors, including safety concerns. Symptomatic complaints are common during pregnancy and may be mistakenly associated with reactions to trivalent influenza vaccine (TIV). To investigate this, we compared post-vaccination events self-reported by pregnant women to events reported by non-pregnant women receiving TIV. Methods: A prospective cohort of 1,086 pregnant women and 314 non-pregnant female healthcare workers (HCWs) who received TIV between March-May 2014 were followed-up seven days post-vaccination to assess local and systemic adverse events following immunisation (AEFIs). Women were surveyed by text message regarding perceived reactions to TIV. Those reporting an AEFI completed an interview by telephone or mobile phone to ascertain details. Logistic regression models adjusting for age and residence were used to compare reactions reported by pregnant women and non-pregnant HCWs. Results: Similar proportions of pregnant women and non-pregnant, female HCWs reported ā‰„1 reaction following vaccination with TIV (13.0% and 17.3%, respectively; OR = 1.2 [95% CI: 0.8-1.8]). Non-pregnant, female HCWs were more likely to report fever or headache compared to pregnant women (OR: 4.6 [95% CI 2.1-10.3] and OR: 2.2 [95% CI 1.0-4.6], respectively). No other significant differences in reported symptoms were observed. No serious vaccine-associated adverse events were reported, and less than 2% of each group sought medical advice for a reaction. Conclusions: We found no evidence suggesting pregnant women are more likely to report adverse events following influenza vaccination when compared to non-pregnant female HCWs of similar age, and in some cases, pregnant women reported significantly fewer adverse events. These results further support the safety of TIV administered in pregnant women

    Two-loop Yang-Mills diagrams from superstring amplitudes

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    Starting from the superstring amplitude describing interactions among D-branes with a constant world-volume field strength, we present a detailed analysis of how the open string degeneration limits reproduce the corresponding field theory Feynman diagrams. A key ingredient in the string construction is represented by the twisted (Prym) super differentials, as their periods encode the information about the background field. We provide an efficient method to calculate perturbatively the determinant of the twisted period matrix in terms of sets of super-moduli appropriate to the degeneration limits. Using this result we show that there is a precise one-to-one correspondence between the degeneration of different factors in the superstring amplitudes and one-particle irreducible Feynman diagrams capturing the gauge theory effective action at the two-loop level.Comment: 42 pages plus appendices, 10 figure

    In utero exposure to butyl benzyl phthalate induces modifications in the morphology and the gene expression profile of the mammary gland: an experimental study in rats

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    <p>Abstract</p> <p>Background</p> <p>Environmental estrogens are exogenous estrogen-mimicking compounds that can interfere with endogenous endocrine systems. Several of these endocrine disruptors have been shown to alter normal development and influence tumorigenesis in experimental models. N-butyl benzyl phthalate (BBP), a widely used plasticizer, is a well-known endocrine disruptor. The aim of this study was to elucidate the effect of prenatal exposure to BBP on the morphology, proliferative index, and genomic signature of the rat mammary gland at different ages.</p> <p>Methods</p> <p><it>In utero </it>exposure was performed by gavage of pregnant Sprague Dawley CD rats with 120mg or 500mg BBP/kg/day from day 10 post-conception to delivery. Female litters were euthanized at 21, 35, 50 and 100 days. The morphology and proliferative index of the mammary gland were studied from whole mount preparations and BrdU incorporation, respectively. Gene expression profile was assessed by microarrays. Several genes found differentially expressed and related to different functional categories were further validated by real time RT-PCR.</p> <p>Results</p> <p>Prenatal exposure of BBP induced delayed vaginal opening and changes in the post-natal mammary gland long after the end of the treatment, mainly by 35 days of age. Exposure to the high dose resulted in modifications in architecture and proliferative index of the mammary gland, mostly affecting the undifferentiated terminal end buds. Moreover, the expression profiles of this gland in the exposed rats were modified in a dose-dependent fashion. Analysis of functional categories showed that modified genes were related to immune function, cell signaling, proliferation and differentiation, or metabolism.</p> <p>Conclusions</p> <p>Our data suggest that <it>in utero </it>exposure to BBP induced a delayed pubertal onset and modified morphology of the mammary gland. These alterations were accompanied by modifications in gene expression previously associated with an increased susceptibility to carcinogenesis.</p
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