227 research outputs found
A Unified Algebraic Framework for Fuzzy Image Compression and Mathematical Morphology
In this paper we show how certain techniques of image processing, having
different scopes, can be joined together under a common "algebraic roof"
Semiring and semimodule issues in MV-algebras
In this paper we propose a semiring-theoretic approach to MV-algebras based
on the connection between such algebras and idempotent semirings - such an
approach naturally imposing the introduction and study of a suitable
corresponding class of semimodules, called MV-semimodules.
We present several results addressed toward a semiring theory for
MV-algebras. In particular we show a representation of MV-algebras as a
subsemiring of the endomorphism semiring of a semilattice, the construction of
the Grothendieck group of a semiring and its functorial nature, and the effect
of Mundici categorical equivalence between MV-algebras and lattice-ordered
Abelian groups with a distinguished strong order unit upon the relationship
between MV-semimodules and semimodules over idempotent semifields.Comment: This version contains some corrections to some results at the end of
Section
Interval valued (\in,\ivq)-fuzzy filters of pseudo -algebras
We introduce the concept of quasi-coincidence of a fuzzy interval value with
an interval valued fuzzy set. By using this new idea, we introduce the notions
of interval valued (\in,\ivq)-fuzzy filters of pseudo -algebras and
investigate some of their related properties. Some characterization theorems of
these generalized interval valued fuzzy filters are derived. The relationship
among these generalized interval valued fuzzy filters of pseudo -algebras
is considered. Finally, we consider the concept of implication-based interval
valued fuzzy implicative filters of pseudo -algebras, in particular, the
implication operators in Lukasiewicz system of continuous-valued logic are
discussed
Theoretical equations of state for temperature and electromagnetic field dependence of fluid systems, based on the quasi-Gaussian entropy theory
The quasi-Gaussian entropy (QGE) theory employs the fact that a free-energy change can be written as the moment-generating function of the appropriate probability distribution function of macroscopic fluctuations of an extensive property. By modeling this distribution, one obtains a model of free energy and resulting thermodynamics as a function of one state variable. In this paper the QGE theory has been extended towards theoretical models or equations of state (EOS’s) of the thermodynamics of semiclassical systems as a function of two state variables. Two “monovariate” QGE models are combined in the canonical ensemble: one based on fluctuations of the excess energy (the confined gamma state giving the temperature dependence) and the other based on fluctuations of the reduced electromagnetic moment [various models as derived in the preceding paper [Apol, Amadei, and Di Nola, J. Chem. Phys. 116, 4426 (2002)], giving the external field dependence]. This provides theoretical EOS’s for fluid systems as a function of both temperature and electromagnetic field. Special limits of these EOS’s are considered: the general weak-field EOS and the limit to a Curie’s law behavior. Based on experimental data of water and simulation data using the extended simple point charge (SPC/E) water model at 45.0 and 55.51 mol/dm3, the specific EOS based on a relatively simple combination of the confined gamma state model with a discrete uniform state field model accurately reproduces the dielectric properties of water at constant density, as the temperature dependence of the weak-field dielectric constant for gases and liquids, and the field dependence of the dielectric constant of liquids
A Comparison of Some Fuzzy Relation-based Linguistic Preference Models for Multiple-Factor Project Assessment
Some approaches to the use of linguistic-preference models based on fuzzy relations in the context of multiple factor project assessment are considered. Projects are characterized in terms of linguistic expressions of 'performance' with respect to factors or impacts and the 'importance' of those factors and impacts. Some variations of methods by Wilhelm and Parsaei (1991) and Eldukair and Ayyub (1992) are considered with some possible analogous methods. A simple illustrative, hypothetical example is developed to compare methods in the context of a proposed bridge river crossing in the city of Brisbane, Queensland, Australia, assessed against six factors: (1) cost, (2) lifespan, (3) usage, (4) aesthetics, (5) construction time, and (6) environmental impact
Statistical Mechanics and Thermodynamics of Simulated Ionic Solutions
In this work we combine molecular dynamics simulations with the quasi-Gaussian entropy (QGE) theory to model the statistical mechanics and thermodynamics of ionic solutions. Results showed that the use of the gamma state model provides an excellent theoretical description of the solution behavior over a wide range of temperature. Such an approach makes possible, at relatively low computational costs, the evaluation of partial molar properties such as free energy and entropy which require a heavy computational effort to be estimated with the usual procedures
Hyperstates of Involutive MTL-Algebras that Satisfy
States of MV-algebras have been the object of intensive study and attempts of
generalizations. The aim of this contribution is to provide a preliminary
investigation for states of prelinear semihoops and hyperstates of algebras in
the variety generated by perfect and involutive MTL-algebras (IBP0-algebras for
short). Grounding on a recent result showing that IBP0-algebras can be
constructed from a Boolean algebra, a prelinear semihoop and a suitably defined
operator between them, our first investigation on states of prelinear semihoops
will support and justify the notion of hyperstate for IBP0- algebras and will
actually show that each such map can be represented by a probability measure on
its Boolean skeleton, and a state on a suitably defined abelian l-group.Comment: 12 page
Efficacy and safety of therapies for COVID-19 in pregnancy: a systematic review and meta-analysis
Background: Clinical evidence suggests that pregnant women are more vulnerable to COVID-19, since they are at increased risk for disease progression and for obstetric complications, such as premature labor, miscarriage, preeclampsia, cesarean delivery, fetal growth restriction and perinatal death. Despite this evidence, pregnant women are often excluded from clinical trials, resulting in limited knowledge on COVID-19 management. The aim of this systematic review and meta-analysis is to provide better evidence on the efficacy and safety of available COVID-19 treatment in pregnant women. Methods: Four authors searched major electronic databases from inception until 1 st November-2022 for controlled trials/observational studies, investigating outcomes after the administration of anti-SARS-CoV-2 treatments in pregnant women affected by COVID-19. The analyses investigated the cumulative incidence of delivery and maternal outcomes in pregnant women, comparing those taking active medication vs standard care. Risk ratios (RRs) with 95% confidence intervals were calculated. Statistical significance was assessed using the random effects model and inverse-variance method. This systematic review and meta-analysis was conducted in accordance with the updated 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol has been registered in Prospero (number registration: CRD42023397445). Results: From initially 937 non duplicate records, we assessed the full texts of 40 articles, finally including ten studies. In six studies, including 1627 patients, the use of casirivimab/imdevimab (CAS/IMD), remdesivir, and IFN-alpha 2b significantly decreased the need of cesarean section ((RR = 0.665; 95%CI: 0.491–0.899; p = 0.008; I 2 = 19.5%;) (Table 1, (Fig. 1). Treatments did not decrease the risk of preterm delivery, admission to neonatal ICU, or stillbirth/perinatal loss (p-values > 0.50 for all these outcomes) and did not prevent the progression of disease towards severe degrees (k = 8; 2,374 pregnant women; RR = 0.778; 95%CI: 0.550–1.099; p = 0.15; I 2 = 0%). Moreover, the use of medications during pregnancy did not modify the incidence of maternal death in two studies (Table 2). Conclusions: To our analysis, CAS/IMD, remdesivir, and IFN alpha 2b reduced the number of cesarean sections but demonstrated no effect on disease progression and other obstetric and COVID-19 related outcomes. The inability to evaluate the influence of viral load on illness development in pregnant women was attributed to lack of data. In our systematic review, no major side effects were reported. Though, it is essential for the medical community to focus more on clinical trials and less on episodic case reports and case series, with standardization of fetal and maternal outcomes
Electron-hole asymmetry in two-terminal graphene devices
A theoretical model is proposed to describe asymmetric gate-voltage
dependence of conductance and noise in two-terminal ballistic graphene devices.
The model is analyzed independently within the self-consistent Hartree and
Thomas-Fermi approximations. Our results justify the prominent role of metal
contacts in recent experiments with suspended graphene flakes. The
contact-induced electrostatic potentials in graphene demonstrate a power-law
decay with the exponent varying from -1 to -0.5. Within our model we explain
electron-hole asymmetry and strong Fabri-Perot oscillations of the conductance
and noise at positive doping, which were observed in many experiments with
submicrometer samples. Limitations of the Thomas-Fermi approximation in a
vicinity of the Dirac point are discussed.Comment: 7 pages, 8 figure
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