scholarly journals When scale is surplus

Synthese ◽  
2021 ◽  
Author(s):  
Sean Gryb ◽  
David Sloan
Keyword(s):  
Kepler Problem ◽  
General Definition ◽  
Galilean Invariance ◽  
Principal Function ◽  
Fundamental Physics ◽  
Dynamical Scaling ◽  
Conceptual Problems ◽  
Definition Of ◽  
Formal Properties ◽  
Dynamical Criterion

AbstractWe study a long-recognised but under-appreciated symmetry called dynamical similarity and illustrate its relevance to many important conceptual problems in fundamental physics. Dynamical similarities are general transformations of a system where the unit of Hamilton’s principal function is rescaled, and therefore represent a kind of dynamical scaling symmetry with formal properties that differ from many standard symmetries. To study this symmetry, we develop a general framework for symmetries that distinguishes the observable and surplus structures of a theory by using the minimal freely specifiable initial data for the theory that is necessary to achieve empirical adequacy. This framework is then applied to well-studied examples including Galilean invariance and the symmetries of the Kepler problem. We find that our framework gives a precise dynamical criterion for identifying the observables of those systems, and that those observables agree with epistemic expectations. We then apply our framework to dynamical similarity. First we give a general definition of dynamical similarity. Then we show, with the help of some previous results, how the dynamics of our observables leads to singularity resolution and the emergence of an arrow of time in cosmology.

scholarly journals A remark on local fractional calculus and ordinary derivatives

2016 ◽  
Vol 14 (1) ◽  
pp. 1122-1124 ◽  
Author(s):  
Ricardo Almeida ◽  
Małgorzata Guzowska ◽  
Tatiana Odzijewicz
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Short Note ◽  
General Definition ◽  
Local Fractional Derivative ◽  
Fundamental Properties ◽  
Local Fractional Calculus ◽  
Definition Of

AbstractIn this short note we present a new general definition of local fractional derivative, that depends on an unknown kernel. For some appropriate choices of the kernel we obtain some known cases. We establish a relation between this new concept and ordinary differentiation. Using such formula, most of the fundamental properties of the fractional derivative can be derived directly.

scholarly journals AB0677 REVISING THE DEFINITION OF REACTIVE ARTHRITIS AND DIFFERENTIATION FROM UNDIFFERENTIATED SPONDYLOARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1633.2-1634
Author(s):  
F. Cosan ◽  
O. M. Gedar
Keyword(s):  
Causative Agent ◽  
Reactive Arthritis ◽  
Case Reports ◽  
Experimental Studies ◽  
Classification Criteria ◽  
General Definition ◽  
Parasitic Infections ◽  
Undifferentiated Spondyloarthritis ◽  
Classical Definition ◽  
Definition Of

Background:Reactive arthritis (ReA) is defined by 1999 ACR criteria as arthritis preceding a bacterial genitourinary (GUS) or gastrointestinal (GIS) infection in 3 days-6 weeks and evidence of triggering infection. Recently, ReA is classified as SpA and patients who do not fulfill SpA criteria are classified as undifferentiated spondyloarthritis (USpA) according to ASAS/EULAR SpA classification criteria.Objectives:In several case reports which are associated with other infective agents are reported and the definition is extended for some clinicians so that SpA which is occurred after any infection is called as ReA. On the other hand, some researchers still accept the classical definition of ReA. The problem with the heterogeneity of opinions and unstandardized definition of ReA hinders studies about pathogenesis and standardization of treatments. In this study, we aimed to determine the spectrum of the use of the definition of reactive arthritis in publications in PubMed between 2009-2019.Methods:The ReA keyword is searched in PubMed for the years between 2009-2019. 248 different publications have been identified and included in this research. 89 articles, 47 reviews, 108 case reports, 2 guidelines, and 2 editorials reviewed for the definition of ReA.Results:Only 42.7% (106 patients) of these publications meet the classical definition which suggests ReA after only GIS and GUS infections. In 4 (1.6%) of the publications ReA was defined after GIS, GUS and oropharyngeal infections; in 3 (1,2%) of the publications after any bacterial infection; in 9 (3.6%) of the publications after any infection. In 8 (3.2%) of the publications, ReA and USPA was used correspondingly. In 39 (15,7%) of the publications the term agent related, ReA was used without making a general definition for ReA. 79 publications (31,9%) have not defined ReA.According to causative agent and ReA relationship, in 64 (24,6%) general infective agents, in 75 (30,2%) classical agents, in 22 (8,9%) other bacterial agents, in 23 (9,3%) streptococcus, in 10(4%) intravesical BCG, in 6 (2.4%) HIV, in 6 (2.4%) tuberculosis, in 12 (4,8%) clostrudium difficle, in 2 (0.8%) parasites were reported. In 31 (12,5%) of the publications the causative agent for the ReA was unknown, the diagnosis was made clinically.Conclusion:In this study, it is aimed to draw attention terminology intricacy and the need for the standardization of the definition of ReA and USpA. It is clear that to standardize the definition of Rea and USpA is necessary. Between 2009-2019 there are reported cases diagnosed as ReA associated with bacterial infections (especially with Clostridium difficile, streptococcus and tuberculosis infections), and viral infections (by a majority with HIV), and parasitic infections. It is not clear if we need to define them classically or define them as USPA. Another important consideration is the necessity of extended laboratory investigations to find out the real causative agent even if the patient is clinically diagnosed with ReA. The requirement of the differentiation between ReA and USpA must be revealed for therapeutic researches.References:[1]A proposal for the classification of patients for clinical and experimental studies on reactive arthritis. Pacheco-Tena C, Burgos-Vargas R, Vázquez-Mellado J, Cazarín J, Pérez-Díaz JA. J Rheumatol. 1999 Jun;26(6):1338-46.[2]The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general. Rudwaleit M, van der Heijde D, Landewé R, Akkoc N, Brandt J, Chou CT, Dougados M, Huang F, Gu J, Kirazli Y, et al. Ann Rheum Dis. 2011;70:25–31.Disclosure of Interests:None declared

scholarly journals A lattice-theoretic characterization of pure subgroups of Abelian groups

2021 ◽  
Author(s):  
M. Ferrara ◽  
M. Trombetti
Keyword(s):  
Abelian Group ◽  
Abelian Groups ◽  
Subgroup Lattice ◽  
General Definition ◽  
Short Paper ◽  
Theoretic Characterization ◽  
Definition Of

AbstractLet G be an abelian group. The aim of this short paper is to describe a way to identify pure subgroups H of G by looking only at how the subgroup lattice $$\mathcal {L}(H)$$ L ( H ) embeds in $$\mathcal {L}(G)$$ L ( G ) . It is worth noticing that all results are carried out in a local nilpotent context for a general definition of purity.

scholarly journals Proportional lumpability and proportional bisimilarity

2021 ◽  
Author(s):  
Andrea Marin ◽  
Carla Piazza ◽  
Sabina Rossi
Keyword(s):  
Markov Chain ◽  
Markov Chains ◽  
Upper And Lower Bounds ◽  
General Definition ◽  
Performance Indices ◽  
State Aggregation ◽  
Structural Regularity ◽  
Original Definition ◽  
Aggregation Technique ◽  
Definition Of

AbstractIn this paper, we deal with the lumpability approach to cope with the state space explosion problem inherent to the computation of the stationary performance indices of large stochastic models. The lumpability method is based on a state aggregation technique and applies to Markov chains exhibiting some structural regularity. Moreover, it allows one to efficiently compute the exact values of the stationary performance indices when the model is actually lumpable. The notion of quasi-lumpability is based on the idea that a Markov chain can be altered by relatively small perturbations of the transition rates in such a way that the new resulting Markov chain is lumpable. In this case, only upper and lower bounds on the performance indices can be derived. Here, we introduce a novel notion of quasi-lumpability, named proportional lumpability, which extends the original definition of lumpability but, differently from the general definition of quasi-lumpability, it allows one to derive exact stationary performance indices for the original process. We then introduce the notion of proportional bisimilarity for the terms of the performance process algebra PEPA. Proportional bisimilarity induces a proportional lumpability on the underlying continuous-time Markov chains. Finally, we prove some compositionality results and show the applicability of our theory through examples.

What Is Fatigue?

2002 ◽  
Vol 27 (1) ◽  
pp. 42-55 ◽  
Author(s):  
Brian R. Macintosh ◽  
Dilson E. Rassier
Keyword(s):  
Contractile Response ◽  
Initial Response ◽  
Calcium Sensitivity ◽  
General Definition ◽  
Light Chains ◽  
Posttetanic Potentiation ◽  
Tetanic Contraction ◽  
First Response ◽  
Definition Of ◽  
Regulatory Light Chain Phosphorylation

Fatigue and potentiation are two forms of force modulation. A general definition of fatigue is "a circumstance where less than the anticipated contractile response is obtained." Fatigue is associated with depressed Ca2+ release and possibly decreased Ca2+ sensitivity. Potentiation results from increased Ca2+ sensitivity due to regulatory light chain phosphorylation. Muscle fatigue and potentiation can coexist, making it difficult to quantify these processes. With repetitive 10 Hz stimulation, the developed tension first increases, then decreases. Is fatigue present when developed tension first begins to decrease or when it falls below the developed tension of the first response? Intermittent incompletely fused tetanic contractions for which peak developed tension first decreases, then increases, is another unusual example of fatigue. A third example is when twitch contractions following a tetanic contraction decrease to a level below the pretetanic twitch amplitude, indicating that fatigue may have been coexistent with posttetanic potentiation. These observations illustrate the complexity of detecting fatigue, based on the simple, but commonly accepted definition presented above. Care must be taken in interpreting "before vs. after" contractile responses. Even when the contraction amplitude is greater than the initial response, there is no guarantee that mechanisms associated with fatigue are not present. Key words: calcium sensitivity, staircase, posttetanic potentiation, myosin light chains, skeletal muscle

scholarly journals General Definition of Gravitational Tension

2004 ◽  
Vol 2004 (05) ◽  
pp. 043-043 ◽  
Author(s):  
T Harmark ◽  
N.A Obers
Keyword(s):  
General Definition ◽  
Definition Of

Mean Diameters in Parallel-Flow and Counter-Flow Aerosol Systems

1976 ◽  
Vol 98 (2) ◽  
pp. 297-302 ◽  
Author(s):  
K. G. T. Hollands ◽  
K. C. Goel
Keyword(s):  
Mass Transfer ◽  
Continuous Phase ◽  
General Concept ◽  
Parallel Flow ◽  
General Definition ◽  
Single Pair ◽  
Counter Flow ◽  
Mean Diameter ◽  
The Mean ◽  
Definition Of

The general concept of the mean diameter of the disperse phase of an aerosol system, first introduced by Mugele and Evans in 1951, has proven to be a very useful one. In this concept, the proper mean diameter, xp,q, is characterized by a single pair of indices, p and q, which are dependent on the actual type of aerosol system under consideration. This paper re-examines the validity of this concept of mean diameter in heat and mass transfer aerosol systems. The concept is found to be applicable only under a very narrow range of conditions. Attention is then given to a more general definition of a mean diameter, applicable to aerosol heat or mass exchangers. Analyses of these devices shows that the more general mean diameter is a function of the capacity rate ratio, R, and effectiveness of the heat exchanger, ε. Solutions to the governing equations have permitted the mean diameter to be presented graphically as a function of these variables. These solutions are given for two types of particle size distributions, the Rosin-Rammler and the log-probability, and for both parallel-flow and counter-flow heat exchangers. The solutions are, however, restricted to cases where the resistance to heat or mass transfer lies exclusively in the continuous phase.

Compare and Analyze of the Definition and Development of Distributed Generation in China and Abroad

2014 ◽  
Vol 953-954 ◽  
pp. 925-928 ◽  
Author(s):  
Bi Bin Huang
Keyword(s):  
Climate Change ◽  
Power Generation ◽  
Energy Conservation ◽  
Distributed Generation ◽  
Basic Characteristic ◽  
Large Scale ◽  
General Definition ◽  
Development Status ◽  
Incentive Policy ◽  
Definition Of

As the positive and important supplement to large-scale power generation, distributed generation (DG) will become key measure to promote energy conservation and solve the problems of climate change in China. Due to absence of universal authoritative definition of DG, this paper summarizes the basic characteristic of DG based on the definitions in typical countries (or organizations) and carried out general definition of DG considering our national conditions and power grid features. From the views of resource, incentive policy and industry, this paper analyzed the fundamental for DG development and compared the development status in typical countries.

DISC HERNIA - DIFFERENTIAL DIAGNOSTICS, OPTION OF PSEUDOTUMOROUS FLOW

Vestnik ◽  
2021 ◽  
pp. 97-101
Author(s):  
М.А. Алиев ◽  
М.Ж. Мирзабаев ◽  
В.С. Караваев
Keyword(s):  
Clinical Medicine ◽  
Clinical Symptoms ◽  
Final Diagnosis ◽  
Herniated Disc ◽  
General Definition ◽  
Differential Diagnostics ◽  
Common Disease ◽  
Physical And Mental Health ◽  
Imaging Results ◽  
Definition Of

Грыжа диска (ГД) является распространенным заболеванием и наносит большой вред как физическому, так и психическому здоровью пациентов, страдающих этим заболеванием. Главным этиологическим фактором заболевания служит дегенерация диска. В настоящее время общее определение грыжи межпозвонкового диска в клинической медицине довольно запутанно. В настоящее время общее определение грыжи межпозвонкового диска в клинической медицине довольно запутанно. Окончательный диагноз ГД основывается на совокупности анамнеза, клинических симптомов и результатах визуализации. Herniated disc is a common disease and causes great harm to both the physical and mental health of patients suffering from this disease. The main etiological factor of the disease is disc degeneration. Currently, the general definition of a herniated disc in clinical medicine is quite confusing. Currently, the general definition of a herniated disc in clinical medicine is quite confusing. The final diagnosis of HD is based on a combination of anamnesis, clinical symptoms, and imaging results.

Clive Bell’s "Metaphysical Hypothesis" and Everyday Aesthetics

2021 ◽  
Vol 1 ◽  
pp. 53-60
Author(s):  
Thomas Leddy ◽  
Keyword(s):  
Everyday Life ◽  
Contemporary Art ◽  
Philosophy Of Art ◽  
Social Meaning ◽  
Surface Level ◽  
Everyday Aesthetics ◽  
The Everyday ◽  
Deep Meaning ◽  
Definition Of ◽  
Formal Properties

Clive Bell’s Art, published in 1913, is widely seen as a founding document in contemporary aesthetics. Yet his formalism and his attendant definition of art as “significant form” is widely rejected in contemporary art discourse and in the philosophy of art. In this paper I argue for a reconsideration of his thought in connection with current discussions of “the aesthetics of everyday life.” Although some, notably Allen Carlson, have argued against application of Bell’s formalism to the aesthetics of everyday life, I claim that this is based on an interpretation of the concept that is overly narrow. First, Li Zehou offers an interpretation of “significant form” that allows in sedimented social meaning. Second, Bell himself offers a more complex theory of significant form by way of his “metaphysical hypothesis,” one that stresses perception of significant form outside the realm of art (for example in nature or in everyday life). Bell’s idea that the artist can perceive significant form in nature allows for significant form to not just be the surface-level formal properties of things. It stresses depth, although a different kind than the cognitive scientific depth Carlson wants. This is a depth that is consistent with the anti-dualism of Spinoza, Marx and Dewey. Reinterpreting Bell in this direction, we can say we are moved by certain relations of lines and colors because they direct our minds to the hidden aspect of things, the spiritual side of the material world referred to by Spinoza and developed by Dewey in his concept of experience. Bell hardly “reduces the everyday to a shadow of itself,” as Carlson puts it, since the everyday, as experienced by the artist or the aesthetically astute observer, has, or potentially has, deep meaning. If we reject Bell’s dualism and his downgrading of sensuous experience, we can rework his idea of pure form to refer to an aspect of things detached, yes, from practical use, but not from particularity or sedimented meaning, not purified of all associations.

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