13,398 research outputs found

    Rotational symmetry of ancient solutions to fully nonlinear curvature flows

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    We address the classification of ancient solutions to fully nonlinear curvature flows for hypersurfaces. Under natural conditions on the speed of motion we classify ancient solutions which are convex, noncollapsing, uniformly two-convex and noncompact. There are exactly two possibilities -- every such solution is either a self-similarly shrinking cylinder, or else is a rotationally symmetric translating soliton. For a large class of flows this yields a complete classification of the blow-up limits that can arise at a singularity of a solution which is compact, embedded and two-convex

    Synthesis and Recognition Properties of Higher Order Tetrathiafulvalene (Ttf) Calix N Pyrroles (N=4-6)

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    Two new benzoTTF-annulated calix[n]pyrroles (n = 5 and 6) were synthesized via a one-step acid catalyzed condensation reaction and fully characterized via single crystallographic analyses. As compared to the known tetra-TTF annulated calix[4]pyrrole, which is also produced under the conditions of the condensation reaction, the expanded calix[n]pyrroles (n = 5 and 6) are characterized by a larger cavity size and a higher number of TTF units (albeit the same empirical formula). Analysis of the binding isotherms obtained from UV-Vis spectroscopic titrations carried out in CHCl3 in the presence of both anionic (Cl-, Br-, I-, CH3COO-, H2PO4-, and HSO4-) and neutral (1,3,5-trinitrobenzene (TNB) and 2,4,6-trinitrotoluene (TNT)) substrates revealed that as a general rule the calix[6]pyrrole derivative proved to be the most efficient molecular receptor for anions, while the calix[4]pyrrole congener proves most effective for the recognition of TNB and TNT. These findings are rationalized in terms of the number of electron rich TTF subunits and NH hydrogen bond donor groups within the series, as well as an ability to adopt conformations suitable for substrate recognition, and are supported by solid state structural analyses.National Science Foundation CHE 1057904, 0741973Robert A. Welch Foundation F-1018Danish Natural Science Research Council (FNU) 272-08-0047, 11-106744WCU (World Class University) program of Korea R32-2010-10217-0Villum FoundationChemistr

    How Long It Takes for an Ordinary Node with an Ordinary ID to Output?

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    In the context of distributed synchronous computing, processors perform in rounds, and the time-complexity of a distributed algorithm is classically defined as the number of rounds before all computing nodes have output. Hence, this complexity measure captures the running time of the slowest node(s). In this paper, we are interested in the running time of the ordinary nodes, to be compared with the running time of the slowest nodes. The node-averaged time-complexity of a distributed algorithm on a given instance is defined as the average, taken over every node of the instance, of the number of rounds before that node output. We compare the node-averaged time-complexity with the classical one in the standard LOCAL model for distributed network computing. We show that there can be an exponential gap between the node-averaged time-complexity and the classical time-complexity, as witnessed by, e.g., leader election. Our first main result is a positive one, stating that, in fact, the two time-complexities behave the same for a large class of problems on very sparse graphs. In particular, we show that, for LCL problems on cycles, the node-averaged time complexity is of the same order of magnitude as the slowest node time-complexity. In addition, in the LOCAL model, the time-complexity is computed as a worst case over all possible identity assignments to the nodes of the network. In this paper, we also investigate the ID-averaged time-complexity, when the number of rounds is averaged over all possible identity assignments. Our second main result is that the ID-averaged time-complexity is essentially the same as the expected time-complexity of randomized algorithms (where the expectation is taken over all possible random bits used by the nodes, and the number of rounds is measured for the worst-case identity assignment). Finally, we study the node-averaged ID-averaged time-complexity.Comment: (Submitted) Journal versio

    Barriers to the development of palliative care in Western Europe

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    The Eurobarometer Survey of the <i>EAPC Task Force on the Development of Palliative Care in Europe</i> is part of a programme of work to produce comprehensive information on the provision of palliative care across Europe. Aim: To identify barriers to the development of palliative care in Western Europe. Method: A qualitative survey was undertaken amongst boards of national associations, eliciting opinions on opportunities for, and barriers to, palliative care development. By July 2006, 44/52 (85%) European countries had responded to the survey; we report here on the results from 22/25 (88%) countries in Western Europe. Analysis: Data from the Eurobarometer survey were analysed thematically by geographical region and by the degree of development of palliative care in each country. Results: From the data contained within the Eurobarometer, we identified six significant barriers to the development of palliative care in Western Europe: (i) Lack of palliative care education and training programmes (ii) Lack of awareness and recognition of palliative care (iii) Limited availability of/knowledge about opioid analgesics (iv) Limited funding (v) Lack of coordination amongst services (vi) Uneven palliative care coverage. Conclusion: Findings from the EAPC Eurobarometer survey suggest that barriers to the development of palliative care in Western Europe may differ substantially from each other in both their scope and context and that some may be considered to be of greater significance than others. A number of common barriers to the development of the discipline do exist and much work still remains to be done in the identified areas. This paper provides a road map of which barriers need to be addressed

    An immunotherapy survivor population: health-related quality of life and toxicity in patients with metastatic melanoma treated with immune checkpoint inhibitors

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    © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Purpose The immune checkpoint inhibitors (ICIs) have resulted in subgroups of patients with metastatic melanoma achievinghigh-quality durable responses. Metastatic melanoma survivors are a new population in the era of cancer survivorship. The aimofthis study was to evaluate metastatic melanoma survivors in terms of health-related quality of life (HRQoL), immune-relatedadverse events (irAEs) and exposure to immunosuppressive agents in a large single centre in the UK.Methods We defined the survivor population as patients with a diagnosis of metastatic melanoma who achieved a durableresponse to an ICI and had been followed-up for a minimum of 12 months from initiation of ICI without disease progression.HRQoL was assessed using SF-36. Electronic health records were accessed to collect data on demographics, treatments, irAEsand survival. HRQoL data was compared with two norm-based datasets.Results Eighty-four metastatic melanoma survivors were eligible and 87% (N = 73) completed the SF-36. ICI-related toxicity ofany grade occurred in 92%of patients and 43%had experienced a grade 3 or 4 toxicity. Almost half (49%) of the patients requiredsteroids for the treatment of ICI-related toxicity, whilst 14% required treatment with an immunosuppressive agent beyondsteroids.Melanoma survivors had statistically significant lower HRQoL scores with regard to physical, social and physical rolefunctioning and general health compared with the normative population. There was a trend towards inferior scores in patientswith previous exposure to ipilimumab compared with those never exposed to ipilimumab.Conclusions Our results show that metastatic melanoma survivors have potentially experienced significant ICI-related toxicityand experience significant impairments in specific HRQoL domains. Future service planning is required to meet this population’sunique survivorship needs.Peer reviewe

    Analysis of surface waves generated on subwavelength-structured silver films

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    Using transmission electron microscopy (TEM) to analyse the physical-chemical surface properties of subwavlength structured silver films and finite-difference time-domain (FDTD) numerical simulations of the optical response of these structures to plane-wave excitation, we report on the origin and nature of the persistent surface waves generated by a single slit-groove motif and recently measured by far-field optical interferometry. The surface analysis shows that the silver films are free of detectable oxide or sulfide contaminants, and the numerical simulations show very good agreement with the results previously reported.Comment: 9 Figure

    Endovascular Embolization of Head and Neck Tumors

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    Endovascular tumor embolization as adjunctive therapy for head and neck cancers is evolving and has become an important part of the tools available for their treatment. Careful study of tumor vascular anatomy and adhering to general principles of intra-arterial therapy can prove this approach to be effective and safe. Various embolic materials are available and can be suited for a given tumor and its vascular supply. This article aims to summarize current methods and agents used in endovascular head and neck tumor embolization and discuss important angiographic and treatment characteristics of selected common head and neck tumors

    The Importance of Forage Legume Inclusion in Agricultural Swards to Enhance Earthworm Activity and Water Infiltration Rates

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    Increased grassland productivity in temperate regions has largely been achieved through perennial ryegrass Lolium perenne (PRG), coupled with large quantities of nitrogen fertiliser. However, concern is growing regarding the negative implications of excessive dependence on nitrogen fertilisers. Research has demonstrated the benefits of legume inclusion on primary productivity, however, their potential to influence other processes is less well established. Sampling was undertaken in autumn 2017 on twenty randomised plots representing five sward types, replicated four times. These had been established and managed by cutting since 2013. Sward types included: 1) PRG (250kg N ha-1 yr-1 ); 2) PRG; 3) PRG and white clover Trifolium repens; 4) 6 species mix comprised of PRG, timothy Phleum pratense, cocksfoot Dactylis glomerata, white clover, red clover Trifolium pratensis and greater birdsfoot trefoil Lotus pedunculatus; 5) species included in mix 4 with the addition of ribwort plantain Plantago lanceolate, chicory Cichorium intybus and yarrow Achillea millefolium. Mixes 2-5 inclusive received 90kg N ha-1 yr-1 . Measurements included: soil bulk density, water infiltration rates, and estimated earthworm activity via surface cast counts. Soil bulk density did not differ in response to sward type. However, highest infiltration rates were recorded within the PRG and white clover swards, with an average of 29.7 (±3.5) mm hr-1 , while lowest rates were recorded from the two PRG monocultures (2.43 (±0.5) and 4.2 (±1.2) mm hr⁻Âč for the 90 and 250 kg N ha-1 yr-1 swards respectively). Surface cast numbers differed significantly between sward types (P\u3c 0.001). Numbers ranged from 127 (±7) casts m⁻ÂČ for PRG & white clover, to 48 (±5) casts m⁻ÂČ for the PRG monocultures. Our findings indicate the importance of legume inclusion within agricultural grasslands managed under reduced nitrogen fertiliser inputs for wider ecosystem service provision
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