58 research outputs found
A characterization of Smyth complete quasi-metric spaces via Caristi's fixed point theorem
We obtain a quasi-metric generalization of Caristi's fixed point theorem for a kind of complete quasi-metric spaces. With the help of a suitable modification of its proof, we deduce a characterization of Smyth complete quasi-metric spaces which provides a quasi-metric generalization of the well-known characterization of metric completeness due to Kirk. Some illustrative examples are also given. As an application, we deduce a procedure which allows to easily show the existence of solution for the recurrence equation of certain algorithms.The authors are grateful to the reviewers for several suggestions which have allowed to improve the first version of the paper. This research is supported by the Ministry of Economy and Competitiveness of Spain, Grant MTM2012-37894-C02-01.Romaguera Bonilla, S.; Tirado PelĂĄez, P. (2015). A characterization of Smyth complete quasi-metric spaces via Caristi's fixed point theorem. Fixed Point Theory and Applications. 2015:183. https://doi.org/10.1186/s13663-015-0431-1S2015:183CobzaĆ, S: Functional Analysis in Asymmetric Normed Spaces. Springer, Basel (2013)KĂŒnzi, HPA: Nonsymmetric distances and their associated topologies: about the origins of basic ideas in the area of asymmetric topology. In: Aull, CE, Lowen, R (eds.) Handbook of the History of General Topology, vol. 3, pp. 853-968. Kluwer Academic, Dordrecht (2001)Reilly, IL, Subrhamanyam, PV, Vamanamurthy, MK: Cauchy sequences in quasi-pseudo-metric spaces. Monatshefte Math. 93, 127-140 (1982)KĂŒnzi, HPA, Schellekens, MP: On the Yoneda completion of a quasi-metric spaces. Theor. Comput. Sci. 278, 159-194 (2002)Romaguera, S, Valero, O: Domain theoretic characterisations of quasi-metric completeness in terms of formal balls. Math. Struct. Comput. Sci. 20, 453-472 (2010)KĂŒnzi, HPA: Nonsymmetric topology. In: Proc. SzekszĂĄrd Conf. Bolyai Society of Math. Studies, vol. 4, pp. 303-338 (1993)GarcĂa-Raffi, LM, Romaguera, S, Schellekens, MP: Applications of the complexity space to the general probabilistic divide and conquer algorithms. J. Math. Anal. Appl. 348, 346-355 (2008)Stoltenberg, RA: Some properties of quasi-uniform spaces. Proc. Lond. Math. Soc. 17, 226-240 (1967)Caristi, J: Fixed point theorems for mappings satisfying inwardness conditions. Trans. Am. Math. Soc. 215, 241-251 (1976)Kirk, WA: Caristiâs fixed point theorem and metric convexity. Colloq. Math. 36, 81-86 (1976)Abdeljawad, T, Karapınar, E: Quasi-cone metric spaces and generalizations of Caristi Kirkâs theorem. Fixed Point Theory Appl. 2009, Article ID 574387 (2009)Acar, O, Altun, I: Some generalizations of Caristi type fixed point theorem on partial metric spaces. Filomat 26(4), 833-837 (2012)Acar, O, Altun, I, Romaguera, S: Caristiâs type mappings on complete partial metric spaces. Fixed Point Theory 14, 3-10 (2013)Aydi, H, Karapınar, E, Kumam, P: A note on âModified proof of Caristiâs fixed point theorem on partial metric spaces, Journal of Inequalities and Applications 2013, 2013:210â. J. Inequal. Appl. 2013, 355 (2013)CobzaĆ, S: Completeness in quasi-metric spaces and Ekeland variational principle. Topol. Appl. 158, 1073-1084 (2011)HadĆŸiÄ, O, Pap, E: Fixed Point Theory in Probabilistic Metric Spaces. Kluwer Academic, Dordrecht (2001)Karapınar, E: Generalizations of Caristi Kirkâs theorem on partial metric spaces. Fixed Point Theory Appl. 2011, 4 (2011)Romaguera, S: A Kirk type characterization of completeness for partial metric spaces. Fixed Point Theory Appl. 2010, Article ID 493298 (2010)Park, S: On generalizations of the Ekeland-type variational principles. Nonlinear Anal. TMA 39, 881-889 (2000)Du, W-S, Karapınar, E: A note on Caristi type cyclic maps: related results and applications. Fixed Point Theory Appl. 2013, 344 (2013)Ali-Akbari, M, Honari, B, Pourmahdian, M, Rezaii, MM: The space of formal balls and models of quasi-metric spaces. Math. Struct. Comput. Sci. 19, 337-355 (2009)Romaguera, S, Schellekens, M: Quasi-metric properties of complexity spaces. Topol. Appl. 98, 311-322 (1999)BrĂžndsted, A: On a lemma of Bishop and Phelps. Pac. J. Math. 55, 335-341 (1974)BrĂžndsted, A: Fixed points and partial order. Proc. Am. Math. Soc. 60, 365-366 (1976)Smyth, MB: Quasi-uniformities: reconciling domains with metric spaces. In: Main, M, Melton, A, Mislove, M, Schmidt, D (eds.) Mathematical Foundations of Programming Language Semantics, 3rd Workshop, Tulane, 1987. Lecture Notes in Computer Science, vol. 298, pp. 236-253. Springer, Berlin (1988)Cull, P, Flahive, M, Robson, R: Difference Equations: From Rabbits to Chaos. Springer, New York (2005)Schellekens, M: The Smyth completion: a common foundation for denotational semantics and complexity analysis. Electron. Notes Theor. Comput. Sci. 1, 535-556 (1995)GarcĂa-Raffi, LM, Romaguera, S, SĂĄnchez-PĂ©rez, EA: Sequence spaces and asymmetric norms in the theory of computational complexity. Math. Comput. Model. 49, 1852-1868 (2009)RodrĂguez-LĂłpez, J, Schellekens, MP, Valero, O: An extension of the dual complexity space and an application to computer science. Topol. Appl. 156, 3052-3061 (2009)Romaguera, S, Schellekens, MP, Valero, O: The complexity space of partial functions: a connection between complexity analysis and denotational semantics. Int. J. Comput. Math. 88, 1819-1829 (2011
Noise Contributions in an Inducible Genetic Switch: A Whole-Cell Simulation Study
Stochastic expression of genes produces heterogeneity in clonal populations of bacteria under identical conditions. We analyze and compare the behavior of the inducible lac genetic switch using well-stirred and spatially resolved simulations for Escherichia coli cells modeled under fast and slow-growth conditions. Our new kinetic model describing the switching of the lac operon from one phenotype to the other incorporates parameters obtained from recently published in vivo single-molecule fluorescence experiments along with in vitro rate constants. For the well-stirred system, investigation of the intrinsic noise in the circuit as a function of the inducer concentration and in the presence/absence of the feedback mechanism reveals that the noise peaks near the switching threshold. Applying maximum likelihood estimation, we show that the analytic two-state model of gene expression can be used to extract stochastic rates from the simulation data. The simulations also provide mRNAâprotein probability landscapes, which demonstrate that switching is the result of crossing both mRNA and protein thresholds. Using cryoelectron tomography of an E. coli cell and data from proteomics studies, we construct spatial in vivo models of cells and quantify the noise contributions and effects on repressor rebinding due to cell structure and crowding in the cytoplasm. Compared to systems without spatial heterogeneity, the model for the fast-growth cells predicts a slight decrease in the overall noise and an increase in the repressors rebinding rate due to anomalous subdiffusion. The tomograms for E. coli grown under slow-growth conditions identify the positions of the ribosomes and the condensed nucleoid. The smaller slow-growth cells have increased mRNA localization and a larger internal inducer concentration, leading to a significant decrease in the lifetime of the repressorâoperator complex and an increase in the frequency of transcriptional bursts
Poxvirus MVA Expressing SARS-CoV-2 S Protein Induces Robust Immunity and Protects Rhesus Macaques From SARS-CoV-2
Novel safe, immunogenic, and effective vaccines are needed to control the COVID-19 pandemic, caused by SARS-CoV-2. Here, we describe the safety, robust immunogenicity, and potent efficacy elicited in rhesus macaques by a modified vaccinia virus Ankara (MVA) vector expressing a full-length SARS-CoV-2 spike (S) protein (MVA-S). MVA-S vaccination was well tolerated and induced S and receptor-binding domain (RBD)-binding IgG antibodies and neutralizing antibodies against SARS-CoV-2 and several variants of concern. S-specific IFNÎł, but not IL-4, -producing cells were also elicited. After SARS-CoV-2 challenge, vaccinated animals showed a significant strong reduction of virus loads in bronchoalveolar lavages (BAL) and decreased levels in throat and nasal mucosa. Remarkably, MVA-S also protected macaques from fever and infection-induced cytokine storm. Computed tomography and histological examination of the lungs showed reduced lung pathology in MVA-S-vaccinated animals. These findings favor the use of MVA-S as a potential vaccine for SARS-CoV-2 in clinical trials.This research was supported by Fondo COVID-19 grant COV20/00151 (Spanish Health Ministry, Instituto de Salud Carlos III (ISCIII)), Fondo Supera COVID-19 grant (Crue Universidades-Banco Santander), and Spanish Research Council (CSIC) grant 202120E079 (to JG-A); CSIC grant 2020E84, la Caixa Banking Foundation grant CF01-00008, Ferrovial, and MAPFRE donations (to ME); a Spanish Ministry of Science and Innovation (MCIN)/Spanish Research Agency (AEI)/10.13039/501100011033 grant (PID2020-114481RB-I00; to JG-A and ME); and internal funding from the BPRC. This research work was also funded by the European Commission-NextGenerationEU, through CSICâs Global Health Platform (PTI Salud Global) (to JG-A and ME). RD received grants from the European Commission Horizon 2020 Framework Programme (Project VIRUSCAN FETPROACT-2016: 731868 and Project EPIC-CROWN-2: 101046084), and FundaciĂłn Caixa-Health Research HR18-00469 (Project StopEbola).Peer reviewe
HE-LHC: The High-Energy Large Hadron Collider â Future Circular Collider Conceptual Design Report Volume 4
In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
A multiâomics approach identifies key regulatory pathways induced by longâterm zinc supplementation in human primary retinal pigment epithelium
In age-related macular degeneration (AMD), both systemic and local zinc levels decline.
Elevation of zinc in clinical studies delayed the progression to end-stage AMD. However, the molecular
pathways underpinning this beneficial effect are not yet identified. In this study, we used differentiated
primary human fetal retinal pigment epithelium (RPE) cultures and long-term zinc supplementation
to carry out a combined transcriptome, proteome and secretome analysis from three genetically
different human donors. After combining significant differences, we identified the complex molecular
networks using Database for Annotation, Visualization and Integrated Discovery (DAVID) and
Ingenuity Pathway Analysis (IPA). The cell cultures from the three donors showed extensive
pigmentation, development of microvilli and basal infoldings and responded to zinc supplementation
with an increase in transepithelial electrical resistance (TEER) (apical supplementation: 443.2 ± 79.3%,
basal supplementation: 424.9 ± 116.8%, compared to control: 317.5 ± 98.2%). Significant changes were
observed in the expression of 1044 genes, 151 cellular proteins and 124 secreted proteins. Gene set
enrichment analysis revealed changes in specific molecular pathways related to cell adhesion/polarity,
extracellular matrix organization, protein processing/transport, and oxidative stress response by zinc
and identified a key upstream regulator effect similar to that of TGFB1
Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future
Purpose Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future. Design Meta-analysis of prevalence data. Participants A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe. Methods AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV). Main Outcome Measures Prevalence of early and late AMD, BCVA, and number of AMD cases. Results Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%â5.0%) in those aged 55â59 years to 17.6% (95%
International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009
The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved
Comparison of Rosco Neo-Sensitabs with Oxoid paper disks in EUCAST disk diffusion antimicrobial susceptibility testing on MuellerâHinton agar
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