171,108 research outputs found
On the Extended Multivalued Geraghty Type Contractions
No full textKARAPINAR, ERDAL/0000-0002-6798-3254; Alsulami, Hamed Hamdan/0000-0001-5188-2830; Afshari, Hojat/0000-0003-1149-4336In this paper we present some absolute retract results for modified Geraghty multivalued type contractions in b-metric space. Our results, generalize several existing results in the corresponding literature. We also present some examples to support the obtained results. (C) 2016 all rights reserved
Fuzzy fixed points of generalized F2-geraghty type fuzzy mappings and complementary results
No full textThe aim of this paper is to introduce generalized F2-Geraghty type fuzzy mappings on a metric space for establishing the existence of fuzzy fixed points of such mappings. As an application of our result, we obtain the existence of common fuzzy fixed point for a generalized F2-Geraghty type fuzzy hybrid pair. These results unify, generalize and complement various known comparable results in the literature. An example and an application to theoretical computer science are presented to support the theory proved herein. Also, to suggest further research on fuzzy mappings, a Feng-Liu type theorem is proved
Response to the editorial by Dr Geraghty
No full textThis article is written in response to the linked editorial by Dr Geraghty about the adaptive Pacing, graded Activity and Cognitive behaviour therapy; a randomised Evaluation (PACE) trial, which we led, implemented and published. The PACE trial compared four treatments for people diagnosed with chronic fatigue syndrome. All participants in the trial received specialist medical care. The trial found that adding cognitive behaviour therapy or graded exercise therapy to specialist medical care was as safe as, and more effective than, adding adaptive pacing therapy or specialist medical care alone. Dr Geraghty has challenged these findings. In this article, we suggest that Dr Geraghty’s views are based on misunderstandings and misrepresentations of the PACE trial; these are corrected
A Discussion on p-Geraghty Contraction on mw-Quasi-Metric Spaces
No full text[EN] In this paper we consider a kind of Geraghty contractions by using mw-distances in the setting of complete quasi-metric spaces. We provide fixed point theorems for this type of mappings and illustrate with some examples the results obtained.This research was partially supported by the Spanish Ministry of Science, Innovation and Universities. Grant number PGC2018-095709-B-C21 and AEI/FEDER, UE funds.Alegre Gil, MC.; Fulga, A.; Karapinar, E.; Tirado Peláez, P. (2020). A Discussion on p-Geraghty Contraction on mw-Quasi-Metric Spaces. Mathematics. 8(9):1-10. https://doi.org/10.3390/math8091437S11089Geraghty, M. A. (1973). On contractive mappings. Proceedings of the American Mathematical Society, 40(2), 604-604. doi:10.1090/s0002-9939-1973-0334176-5Gupta, V., Shatanawi, W., & Mani, N. (2016). Fixed point theorems for ( ψ , β ) -Geraghty contraction type maps in ordered metric spaces and some applications to integral and ordinary differential equations. Journal of Fixed Point Theory and Applications, 19(2), 1251-1267. doi:10.1007/s11784-016-0303-2Cho, S.-H., Bae, J.-S., & Karapınar, E. (2013). Fixed point theorems for α-Geraghty contraction type maps in metric spaces. Fixed Point Theory and Applications, 2013(1). doi:10.1186/1687-1812-2013-329Alegre, C., & Marín, J. (2016). Modified w-distances on quasi-metric spaces and a fixed point theorem on complete quasi-metric spaces. Topology and its Applications, 203, 32-41. doi:10.1016/j.topol.2015.12.073Alegre Gil, C., Karapınar, E., Marín Molina, J., & Tirado Peláez, P. (2019). Revisiting Bianchini and Grandolfi Theorem in the Context of Modified -Distances. Results in Mathematics, 74(4). doi:10.1007/s00025-019-1074-zAlegre, C., Marín, J., & Romaguera, S. (2014). A fixed point theorem for generalized contractions involving w-distances on complete quasi-metric spaces. Fixed Point Theory and Applications, 2014(1). doi:10.1186/1687-1812-2014-40Park, S. (2000). On generalizations of the Ekeland-type variational principles. Nonlinear Analysis: Theory, Methods & Applications, 39(7), 881-889. doi:10.1016/s0362-546x(98)00253-
A logistic regression analysis of risk factors in ME/CFS pathogenesis
No full textBackground: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex disease, whose exact
cause remains unclear. A wide range of risk factors has been proposed that helps understanding potential disease
pathogenesis. However, there is little consistency for many risk factor associations, thus we undertook an
exploratory study of risk factors using data from the UK ME/CFS Biobank participants. We report on risk factor
associations in ME/CFS compared with multiple sclerosis participants and healthy controls.
Methods: This was a cross-sectional study of 269 people with ME/CFS, including 214 with mild/moderate and 55
with severe symptoms, 74 people with multiple sclerosis (MS), and 134 healthy controls, who were recruited from
primary and secondary health services. Data were collected from participants using a standardised written
questionnaire. Data analyses consisted of univariate and multivariable regression analysis (by levels of proximity to
disease onset).
Results: A history of frequent colds (OR = 8.26, P <= 0.001) and infections (OR = 25.5, P = 0.015) before onset were
the strongest factors associated with a higher risk of ME/CFS compared to healthy controls. Being single (OR = 4.41,
P <= 0.001), having lower income (OR = 3.71, P <= 0.001), and a family history of anxiety is associated with a higher
risk of ME/CFS compared to healthy controls only (OR = 3.77, P < 0.001). History of frequent colds (OR = 6.31, P <
0.001) and infections before disease onset (OR = 5.12, P = 0.005), being single (OR = 3.66, P = 0.003) and having
lower income (OR = 3.48, P = 0.001), are associated with a higher risk of ME/CFS than MS. Severe ME/CFS cases were
associated with lower age of ME/CFS onset (OR = 0.63, P = 0.022) and a family history of neurological illness
(OR = 6.1, P = 0.001).
Conclusions: Notable differences in risk profiles were found between ME/CFS and healthy controls, ME/CFS and
MS, and mild-moderate and severe ME/CFS. However, we found some commensurate overlap in risk associations
between all cohorts. The most notable difference between ME/CFS and MS in our study is a history of recent
infection prior to disease onset. Even recognising that our results are limited by the choice of factors we selected to
investigate, our findings are consistent with the increasing body of evidence that has been published about the
potential role of infections in the pathogenesis of ME/CFS, including common colds/flu
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
SOME FIXED POINT THEOREMS FOR GENERALIZED -GERAGHTY CONTRACTION TYPE MAPPINGS IN -METRIC~SPACES AND SOME APPLICATIONS TO THE NONLINEAR INTEGRAL EQUATION
No full textThe purpose of this paper is to introduce the notion of a generalized -Geraghty contraction type mapping in -metric~spaces and state the existence and uniqueness of a fixed point for this mapping. These results are generalizations of certain the main results in [D.~\DJ uki\'{c}, Z.~Kadelburg, and S.~Radenovi\'{c}, \emph{Fixed points of Geraghty-type mappings in various generalized metric spaces}, Abstr. Appl. Anal. \textbf{2011} (2011), 13 pages] and [O.~Popescu, \emph{ Some new fixed point theorems for -Geraghty contraction type maps in metric spaces}, Fixed Point Theory Appl. \textbf{2014:190} (2014), 1 -- 12]. Some examples are given to illustrate the obtained results and to show that these results are proper extensions of the existing ones. Then we apply the obtained theorem to study the existence of solutions to the nonlinear integral equation
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