2,107 research outputs found

    Affine actions on non-archimedean trees

    Full text link
    We initiate the study of affine actions of groups on Λ\Lambda-trees for a general ordered abelian group Λ\Lambda; these are actions by dilations rather than isometries. This gives a common generalisation of isometric action on a Λ\Lambda-tree, and affine action on an R\R-tree as studied by I. Liousse. The duality between based length functions and actions on Λ\Lambda-trees is generalised to this setting. We are led to consider a new class of groups: those that admit a free affine action on a Λ\Lambda-tree for some Λ\Lambda. Examples of such groups are presented, including soluble Baumslag-Solitar groups and the discrete Heisenberg group.Comment: 27 pages. Section 1.4 expanded, typos corrected from previous versio

    The intrinsic Baldwin effect in broad Balmer lines of six long-term monitored AGNs

    Full text link
    We investigate the intrinsic Baldwin effect (Beff) of the broad Hα\alpha and Hβ\beta emission lines for six Type 1 active galactic nuclei (AGNs) with different broad line characteristics: two Seyfert 1 (NGC 4151 and NGC 5548), two AGNs with double-peaked broad line profiles (3C 390.3 and Arp 102B), one narrow line Seyfert 1 (Ark 564), and one high-luminosity quasar with highly red asymmetric broad line profiles (E1821+643). We found that a significant intrinsic Beff was present in all Type 1 AGNs in our sample. Moreover, we do not see strong difference in intrinsic Beff slopes in different types of AGNs which probably have different physical properties, such as inclination, broad line region geometry, or accretion rate. Additionally, we found that the intrinsic Beff was not connected with the global one, which, instead, could not be detected in the broad Hα\alpha or Hβ\beta emission lines. In the case of NGC 4151, the detected variation of the Beff slope could be due to the change in the site of line formation in the BLR. Finally, the intrinsic Beff might be caused by the additional optical continuum component that is not part of the ionization continuum.Comment: 12 pages, 8 figures, Accepted for publication in A&

    Xerostomia induced by radiotherapy: an overview of the physiopathology, clinical evidence, and management of the oral damage

    Get PDF
    Background: The irradiation of head and neck cancer (HNC) often causes damage to the salivary glands. The resulting salivary gland hypofunction and xerostomia seriously reduce the patient\u2019s quality of life. Purpose: To analyze the literature of actual management strategies for radiation-induced hypofunction and xerostomia in HNC patients. Methods: MEDLINE/PubMed and the Cochrane Library databases were electronically evaluated for articles published from January 1, 1970, to June 30, 2013. Two reviewers independently screened and included papers according to the predefined selection criteria. Results: Sixty-one articles met the inclusion criteria. The systematic review of the literature suggests that the most suitable methods for managing the clinical and pathophysiological consequences of HNC radiotherapy might be the pharmacological approach, for example, through the use of cholinergic agonists when residual secretory capacity is still present, and the use of salivary substitutes. In addition, a modified diet and the patient\u2019s motivation to enhance oral hygiene can lead to a significant improvement. Conclusion: Radiation-induced xerostomia could be considered a multifactorial disease. It could depend on the type of cancer treatment and the cumulative radiation dose to the gland tissue. A preventive approach and the correct treatment of the particular radiotherapeutic patient can help to improve the condition of xerostomia

    Photo-electro-chemical properties of TiO2 mediated by the enzyme glucose oxidase

    Get PDF
    Electrochemical measurements show that the enzyme Glucose oxidase (GO) is adsorbed on the surface of TiO2 without apparently changing the flat band potential of the semiconductor, indicating that it does not cause a change of the energy of conduction band electrons. On the other hand, it is observed that GO markedly increases the efficiency of the two electron reduction of O2 to H2O2 which is accumulated in the solution phase. ESR spin trapping investigations indicate that GO favors the formation of OH . radicals, due to either the inhibition of charge recombination processes or to H2O2 reduction by conduction band electrons. Accordingly, photo-oxidation of different alcohols to the corresponding radical species is also enhanced in the presence of GO. The photo-oxidation of 1,2-propandiol on TiO2/GO is regioselective in that i) partial oxidation to hydroxyacetone is observed and ii) no mineralization (full combustion to CO2) of the substrate occurs. These facts are of particular interest in the field of studies concerning the design of new photocatalytic systems with enhanced activity and controllable oxidative power

    High levels of memory B cells are associated with response to a first tumor necrosis factor inhibitor in patients with rheumatoid arthritis in a longitudinal prospective study

    Get PDF
    Tumor necrosis factor inhibitor (TNFi) therapy is effective for rheumatoid arthritis (RA). Some reports suggested that the therapy affects B-cell homeostasis. We studied the effect of TNFi therapy on the distribution of peripheral B-cell subsets and elucidated B-cell-related biomarkers to predict the TNFi response. Peripheral B cells were analyzed for expression of CD19, CD27, CD38, and IgD in 31 healthy donors and 96 RA patients, including 21 who were followed 3 months after TNFi introduction. Treatment with steroids significantly altered the distribution of B-cell subsets. After adjustment for age, gender and steroid dose, patients with RA had similar B-cell subset proportions as controls. B-cell subset distribution did not differ by use of TNFi at baseline or before and after TNFi introduction. TNFi responders (according to European League Against Rheumatism criteria) at 3 months had significantly higher proportion of CD27+ memory B cells at baseline, and >= 26% CD27+ cells at inclusion was associated with a relative risk of 4.9 (1.3 to 18.6) of responding to TNFi treatment. CD27+ cells produced 3 times more TNFalpha than did naive B cells, and were correlated with interferon-gamma produced from CD4+ cells in patients without TNFi treatment. In patients with RA, high levels of baseline memory B cells were associated with response to TNFi, which may be related to TNFalpha-dependent activation of the T helper cell type 1 pathwa

    Development of an Optimization-Based Atomistic-to-Continuum Coupling Method

    Full text link
    Atomistic-to-Continuum (AtC) coupling methods are a novel means of computing the properties of a discrete crystal structure, such as those containing defects, that combine the accuracy of an atomistic (fully discrete) model with the efficiency of a continuum model. In this note we extend the optimization-based AtC, formulated in arXiv:1304.4976 for linear, one-dimensional problems to multi-dimensional settings and arbitrary interatomic potentials. We conjecture optimal error estimates for the multidimensional AtC, outline an implementation procedure, and provide numerical results to corroborate the conjecture for a 1D Lennard-Jones system with next-nearest neighbor interactions.Comment: 12 pages, 3 figure

    Epidemiology of intensive care unit-acquired sepsis in Italy: results of the SPIN-UTI network

    Get PDF
    BACKGROUND: Sepsis is the major cause of mortality from any infectious disease worldwide. Sepsis may be the result of a healthcare associated infection (HAI): the most frequent adverse events during care delivery especially in Intensive Care Units (ICUs). The main aim of the present study was to describe the epidemiology of ICU-acquired sepsis and related outcomes among patients enrolled in the framework of the Italian Nosocomial Infections Surveillance in ICUs - SPIN-UTI project. STUDY DESIGN: Prospective multicenter study. METHODS: The SPIN-UTI network adopted the European protocols for patient-based HAI surveillance. RESULTS: During the five editions of the SPIN-UTI project, from 2008 to 2017, 47.0% of HAIs has led to sepsis in 832 patients. Overall, 57.0% episodes were classified as sepsis, 20.5% as severe sepsis and 22.5% as septic shock. The most common isolated microorganisms from sepsis episodes were Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. The case fatality rate increased with the severity of sepsis and the mean length of ICU-stay was significantly higher in patients with ICU-acquired sepsis than in patients without. CONCLUSION: Our study provides evidence that ICU-acquired sepsis occurs frequently in Italian ICU patients and is associated with a high case fatality rate and increased length of stay. However, in order to explain these findings further analyses are needed in this population of ICU patient

    Long-term monitoring of the broad-line region properties in a selected sample of AGN

    Full text link
    We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.Comment: Published in Frontiers in Astronomy and Space Scienc
    corecore