scholarly journals A comparison theorem for cosmological lightcones

2021 ◽  
Vol 111 (2) ◽  
Author(s):  
Mauro Carfora ◽  
Francesca Familiari
Keyword(s):  
Scalar Curvature ◽  
Variational Analysis ◽  
Length Scale ◽  
Leading Order ◽  
Spacetime Geometry ◽  
The Family ◽  
Physical Spacetime ◽  
The Given ◽  
Natural Scale ◽  
Cosmological Spacetime

AbstractLet (M, g) denote a cosmological spacetime describing the evolution of a universe which is isotropic and homogeneous on large scales, but highly inhomogeneous on smaller scales. We consider two past lightcones, the first, $${{\mathcal {C}}_{L}^{-}}(p, g)$$ C L - ( p , g ) , is associated with the physical observer $$p\in \,M$$ p ∈ M who describes the actual physical spacetime geometry of (M, g) at the length scale L, whereas the second, $${\mathcal {C}_{L}^{-}}(p, \hat{g})$$ C L - ( p , g ^ ) , is associated with an idealized version of the observer p who, notwithstanding the presence of local inhomogeneities at the given scale L, wish to model (M, g) with a member $$(M, \hat{g})$$ ( M , g ^ ) of the family of Friedmann–Lemaitre–Robertson–Walker spacetimes. In such a framework, we discuss a number of mathematical results that allows a rigorous comparison between the two lightcones $${\mathcal {C}_{L}^{-}}(p, g)$$ C L - ( p , g ) and $${\mathcal {C}_{L}^{-}}(p, \hat{g})$$ C L - ( p , g ^ ) . In particular, we introduce a scale-dependent (L) lightcone-comparison functional, defined by a harmonic type energy, associated with a natural map between the physical $${\mathcal {C}_{L}^{-}}(p, g)$$ C L - ( p , g ) and the FLRW reference lightcone $${\mathcal {C}_{L}^{-}}(p, \hat{g})$$ C L - ( p , g ^ ) . This functional has a number of remarkable properties, in particular it vanishes iff, at the given length-scale, the corresponding lightcone surface sections (the celestial spheres) are isometric. We discuss in detail its variational analysis and prove the existence of a minimum that characterizes a natural scale-dependent distance functional between the two lightcones. We also indicate how it is possible to extend our results to the case when caustics develop on the physical past lightcone $${\mathcal {C}_{L}^{-}}(p, g)$$ C L - ( p , g ) . Finally, by exploiting causal diamond theory, we show how the distance functional is related (to leading order in the scale L) to spacetime scalar curvature in the causal past of the two lightcones, and briefly illustrate a number of its possible applications.

scholarly journals Televisión abuse on our students´s side: how, when and why

Comunicar ◽  
2005 ◽  
Vol 13 (25) ◽  
Author(s):  
María-de-la-Cinta Aguaded-Gómez
Keyword(s):  
Primary Education ◽  
Negative Influence ◽  
Free Time ◽  
Social Aspects ◽  
Educational Community ◽  
Educational Levels ◽  
The Family ◽  
The World ◽  
Educación Primaria ◽  
The Given

The abuse of over watching Television by our alumnae is a fact that worries all the educational community. Every day, the teachers observe how the alumnae, at all educational levels, follow patterns of behaviour, keeping values and reproducing roles that have been seen and defended by our television stations. This abuse leads to a series of implications, not only in the educational area, but in the family circle as well, in relational and social aspects. Our aim is to know the negative influence of this phenomena on a particular population, and to contrast the results with other investigations developed in other contexts. This study was initiated on a group of alumnae form the 2º term of primary education, in the province of Huelva. The principal objective consisted of deepening the awareness in the world of our pupils: questioning the use of their free time and knowing their habits and behaviour. Finding out the amount of time they dedicate to watching television, where they watch it, with whom and why it attracts them so enormously. First of all, the qualities presented on television to attract the infant population was analysed, afterwards a sample of the studied population was selected, specifying the context where it was to be taken and the characteristics of the area, its educational centres and studied alumnae. Later, it was selected the instruments of data collected, among them, the questionnaire. Finally, study implications to determine the given conclusions were obtained. El abuso de la televisión por parte de nuestros alumnos es un hecho que preocupa a toda la comunidad educativa. Cada día los docentes observan cómo el alumnado de todos los niveles educativos sigue pautas de comportamientos, mantiene valores y reproduce modelos que han sido visionados y defendidos por nuestras televisiones. Este abuso conlleva una serie de implicaciones no sólo en el ámbito educativo sino también en el familiar y en consecuencia en el relacional y social. Con el propósito de conocer cómo influye este fenómeno en una población determinada y contrastar los resultados con otras investigaciones realizadas en otros contextos se inició este estudio en un grupo de alumnos del 2º ciclo de educación primaria de la provincia de Huelva. El objetivo principal consistía en profundizar en el mundo de nuestros escolares: indagando en el uso de su tiempo libre y conociendo sus hábitos y conductas, averiguando qué tiempo dedican a ver la televisión, dónde la visionan, con quién y porqué les atraía enormemente. En un primer momento se analizaron las cualidades que presentaba la televisión para atraer a la población infantil, seguidamente se selecciono la muestra de la población estudiada especificando el contexto donde se iba a llevar a cabo y las características de la zona, sus centros educativos y los alumnos estudiados. Seguidamente se seleccionaron los instrumentos de recogida de datos, entre ellos el cuestionario. Finalmente se obtuvieron unas implicaciones del estudio para detallar las conclusiones obtenidas.

Some necessary corrections of the spelling of species-group names within the family Dytiscidae (Coleoptera)

Zootaxa ◽  
2007 ◽  
Vol 1615 (1) ◽  
pp. 49-54 ◽  
Author(s):  
ANDERS N. NILSSON
Keyword(s):  
Species Group ◽  
Personal Names ◽  
The Family ◽  
The Given

The spelling of 37 species-group names with the beetle family Dytiscidae is corrected relative to the most recent world catalogue. The original spelling of 11 specific and subspecific names based on personal names are considered incorrect as having the wrong suffix relative to the given etymology. For three specific names, the original spelling is considered correct, and the previously used corrections are unjustified. The remaining names dealt with are adjectives, or nouns misinterpreted as adjectives, and their inflection relative to the genus names is revised.

scholarly journals Wrinkling of a thin circular sheet bonded to a spherical substrate

2017 ◽  
Vol 375 (2093) ◽  
pp. 20160157 ◽  
Author(s):  
Peter Bella ◽  
Robert V. Kohn
Keyword(s):  
Small Parameter ◽  
Radial Strain ◽  
Media Theory ◽  
Order Correction ◽  
Upper And Lower Bounds ◽  
Normal Displacement ◽  
Length Scale ◽  
Leading Order ◽  
Piecewise Constant ◽  
Macroscopic Deformation

We consider a disc-shaped thin elastic sheet bonded to a compliant sphere. (Our sheet can slip along the sphere; the bonding controls only its normal displacement.) If the bonding is stiff (but not too stiff), the geometry of the sphere makes the sheet wrinkle to avoid azimuthal compression. The total energy of this system is the elastic energy of the sheet plus a (Winkler-type) substrate energy. Treating the thickness of the sheet h as a small parameter, we determine the leading-order behaviour of the energy as h tends to zero, and we give (almost matching) upper and lower bounds for the next-order correction. Our analysis of the leading-order behaviour determines the macroscopic deformation of the sheet; in particular, it determines the extent of the wrinkled region, and predicts the (non-trivial) radial strain of the sheet. The leading-order behaviour also provides insight about the length scale of the wrinkling, showing that it must be approximately independent of the distance r from the centre of the sheet (so that the number of wrinkles must increase with r ). Our results on the next-order correction provide insight about how the wrinkling pattern should vary with r . Roughly speaking, they suggest that the length scale of wrinkling should not be exactly constant—rather, it should vary slightly, so that the number of wrinkles at radius r can be approximately piecewise constant in its dependence on r , taking values that are integer multiples of h − a with . This article is part of the themed issue ‘Patterning through instabilities in complex media: theory and applications’.

scholarly journals Systemic approach to сhild psychiatry: insights in etiopathogenesis and organization of assistance

2020 ◽  
Vol 27 (4) ◽  
pp. 475-486
Author(s):  
Marina A. Bebchuk
Keyword(s):  
Well Being ◽  
Practical Experience ◽  
Structural Aspect ◽  
Social Adaptation ◽  
Systemic Approach ◽  
Phobic Anxiety ◽  
The Family ◽  
Medical Histories ◽  
The Given ◽  
Mental Well Being

Aim. Integration of information on systemic approach published in literature, and of the own practical experience in rendering psychotherapeutic assistance to children with different forms of phobic anxiety disorders (PAD) aimed at improvement of effectiveness of treatment, of social adaptation of patients with PAD, and at search for organization forms of medical assistance to the given category of childrens population. Materials and Methods. Into the study 61 children of 8-17 years old were involved living at home and admitted to G.E. Sukharevskaya Research and Practical Center of Mental Well-Being of Children and Adolescents in 2018 for different mental disorders including PAD. In the study, analysis of medical histories and protocols of classes with a family psychologist were used. Results. On the basis of the parameters of family functioning three groups of phobic anxiety syndromes were isolated: disorders of the structural aspect (limits, hierarchy, coalitions, triangles), disorders of communication sphere, or of family history. The working systemic hypotheses were illustrated with ten classic examples. Conclusion. Systemic hypotheses of formation of PAD in children permit to construct treatment and rehabilitation strategies directed at improvement of patients state through creation of conditions for a prolonged stable remission in the family. Inclusion of classes with a family psychologist/psychotherapist into the plan of treatment and rehabilitation permits to shift the accent of help to a child to the outpatient environment.

scholarly journals The Bases of Postmodernism in Harold Pinter’s play “The Homecoming”

2018 ◽  
Vol 6 (3) ◽  
pp. 151-157
Author(s):  
Salome Davituliani
Keyword(s):  
Family Relationships ◽  
Modern World ◽  
Essential Characteristic ◽  
The Family ◽  
Simple Language ◽  
The Given

Abstract The modern world, in which we live, is regarded as the period of postmodernism. In this period it is hard to perceive the reality in a right way. So are Harold Pinter’s plays. Mostly they are somewhere between reality and absurdity. Based on his writings, he is considered to be, one of the first postmodernist authors. The simplicity of the dialogues makes the feeling that the play is easy to understand, but after reading/watching all the relationships between the characters you feel a bit confused. Nothing is real, and exactly this is the reality of their world, not to be real. And not only the relationships but the characters themselves do not know who they are in reality and it is hard for them to identify their own personality. As it has been already mentioned above, in Pinter’s plays, we can easily find the elements of postmodernism. In the given papers this idea will be expressed depending on the play “The Homecoming”, where Pinter presents us so-called “family”, the group of people, and shows us their emptiness from the family relationships. Even relationships between father and sons, and wife and husband are not real. All this are presented with the very simple language and this is also the essential characteristic of the postmodern world, also the difficulty of understanding each other, and almost meaningless words. Pinter uses other forms of communication such as pauses and silences, in a manner typical of postmodernism. There should be also noted that “the homecoming” the title itself, makes the reader/audience confused, the expectation about perceiving the title at the beginning does not coincide the perception of it in the ending part. The aim of this paper is to highlight the key elements of postmodernism in Harold Pinter’s play “The Homecoming” and to show us once again, that Pinter’s works are really important in our postmodern world.

scholarly journals Shiraishi functor and non-Kerov deformation of Macdonald polynomials

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Hidetoshi Awata ◽  
Hiroaki Kanno ◽  
Andrei Mironov ◽  
Alexei Morozov
Keyword(s):  
Network Models ◽  
Elliptic Systems ◽  
Macdonald Polynomials ◽  
Symmetric Polynomials ◽  
Leading Order ◽  
Young Diagrams ◽  
Schur Polynomials ◽  
Pochhammer Symbol ◽  
The Family ◽  
Two Kinds Of Variables

AbstractWe suggest a further generalization of the hypergeometric-like series due to M. Noumi and J. Shiraishi by substituting the Pochhammer symbol with a nearly arbitrary function. Moreover, this generalization is valid for the entire Shiraishi series, not only for its Noumi–Shiraishi part. The theta function needed in the recently suggested description of the double-elliptic systems [Awata et al. JHEP 2020:150, arXiv:2005.10563, (2020)], 6d N = 2* SYM instanton calculus and the doubly-compactified network models, is a very particular member of this huge family. The series depends on two kinds of variables, $$\vec {x}$$ x → and $$\vec {y}$$ y → , and on a set of parameters, which becomes infinitely large now. Still, one of the parameters, p is distinguished by its role in the series grading. When $$\vec {y}$$ y → are restricted to a discrete subset labeled by Young diagrams, the series multiplied by a monomial factor reduces to a polynomial at any given order in p. All this makes the map from functions to the hypergeometric-like series very promising, and we call it Shiraishi functor despite it remains to be seen, what are exactly the morphisms that it preserves. Generalized Noumi–Shiraishi (GNS) symmetric polynomials inspired by the Shiraishi functor in the leading order in p can be obtained by a triangular transform from the Schur polynomials and possess an interesting grading. They provide a family of deformations of Macdonald polynomials, as rich as the family of Kerov functions, still very different from them, and, in fact, much closer to the Macdonald polynomials. In particular, unlike the Kerov case, these polynomials do not depend on the ordering of Young diagrams in the triangular expansion.

scholarly journals PRELIMINARY PHYTOCHEMICAL SCREENING AND EVALUATION OF MUSCLE RELAXANT ACTIVITY OF ETHANOLIC EXTRACT OF RHIZOME OF ZINGIBEROFFICINALE

2017 ◽  
pp. 13-16
Author(s):  
Juri Das ◽  
Dipankar Saha
Keyword(s):  
Muscle Relaxant ◽  
Ethanolic Extract ◽  
Zingiber Officinale ◽  
P Value ◽  
Phytochemical Screening ◽  
Standard Drug ◽  
The Family ◽  
Muscle Relaxant Activity ◽  
The Given ◽  
Dose Dependent

Objective: The aim of this study to investigate the Preliminary Phytochemical Screening and evaluation of Muscle relaxant activity of ethanolic extract of Zingiberofficinale (EEZO) belonging to the family Zingiberaceae using Swiss albino mice in comparison with that of standard drug (Lorazepam).Methods: The phytochemical screening of the EEZO was done as per the standard methods. Then the extract was evaluated for its muscle relaxant activity compared with Control which is Normal saline (0.9% NaCl solution) at a dose of 10 ml/kg and standard drug Lorazepam at a dose of 10 mg/kg p. o by using Rota-rod apparatus. Twenty mice were taken of either sex and are divided into four groups and each group contains five animals. The first group was considered as control, the second group considered as standard and the third and fourth group received extracts (EEZO) at a dose of 100 mg/kg and 200 mg/kg p. o respectively. All the preparations were administered orally.Results: The Preliminary Phytochemical screening of Ethanolic plant extract of Zingiberofficinale showed the presence of alkaloids, Carbohydrates, phlobotannins, flavonoids, glycosides, saponins, tannin and terpenoids and absence of steroids. The two doses of EEZO i.e. 100 mg/kg (7.8±0.421 sec) and 200 mg/kg (3.07±0.385) significantly reduced the fall of time in the Rota-rod apparatus as compared to control (48.67±1.112) with p value<0.0001. The result is quite satisfying when compared with the standard drug i.e. 10 mg/kg p. o. (6.2±0.331).Conclusion: The result of the given study demonstrated that the ethanolic extract of Zingiber officinale is having Dose Dependent Muscle Relaxant activity.

ON THE PROBLEM OF RESTORING A FUNCTION IN THREE DIMENSIONAL SPACE BY THE FAMILY OF CONES

2021 ◽  
Vol 10 (11) ◽  
pp. 3505-3513
Author(s):  
Z.Kh. Ochilov ◽  
M.I. Muminov
Keyword(s):  
Weight Function ◽  
Exact Solutions ◽  
Special Form ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Weight Functions ◽  
The Family ◽  
The Given ◽  
Three Dimensional Space

In this paper, we consider the problem of recovering a function in three-dimensional space from a family of cones with a weight function of a special form. Exact solutions of the problem are obtained for the given weight functions. A class of parameters for the problem that has no solution is constructed.

Nonlinear effects in two-layer large-amplitude geostrophic dynamics. Part 1. The strong-beta case

2000 ◽  
Vol 412 ◽  
pp. 125-160 ◽  
Author(s):  
RICHARD H. KARSTEN ◽  
GORDON E. SWATERS
Keyword(s):  
Large Amplitude ◽  
Nonlinear Effects ◽  
Breaking Waves ◽  
Short Wave ◽  
Finite Amplitude ◽  
Length Scale ◽  
Leading Order ◽  
Length Scales ◽  
Geostrophic Balance ◽  
Suitable Framework

Baroclinic large-amplitude geostrophic (LAG) models, which assume a leading-order geostrophic balance but allow for large-amplitude isopycnal deflections, provide a suitable framework to model the large-amplitude motions exhibited in frontal regions. The qualitative dynamical characterization of LAG models depends critically on the underlying length scale. If the length scale is sufficiently large, the effect of differential rotation, i.e. the β-effect, enters the dynamics at leading order. For smaller length scales, the β-effect, while non-negligible, does not enter the dynamics at leading order. These two dynamical limits are referred to as strong-β and weak-β models, respectively.A comprehensive description of the nonlinear dynamics associated with the strong- β models is given. In addition to establishing two new nonlinear stability theorems, we extend previous linear stability analyses to account for the finite-amplitude development of perturbed fronts. We determine whether the linear solutions are subject to nonlinear secondary instabilities and, in particular, a new long-wave–short-wave (LWSW) resonance, which is a possible source of rapid unstable growth at long length scales, is identified. The theoretical analyses are tested against numerical simulations. The simulations confirm the importance of the LWSW resonance in the development of the flow. Simulations show that instabilities associated with vanishing potential- vorticity gradients can develop into stable meanders, eddies or breaking waves. By examining models with different layer depths, we reveal how the dynamics associated with strong-β models qualitatively changes as the strength of the dynamic coupling between the barotropic and baroclinic motions varies.

scholarly journals Ungiven: Philanthropy as critique

2018 ◽  
Vol 52 (1) ◽  
pp. 325-350 ◽  
Author(s):  
DWAIPAYAN BANERJEE ◽  
JACOB COPEMAN
Keyword(s):  
Prime Minister ◽  
Blood Donation ◽  
Field Research ◽  
North India ◽  
Not Given ◽  
Communal Violence ◽  
The Family ◽  
Indian State ◽  
The Given ◽  
Do So

AbstractDrawing on field research principally from contexts of medical blood donation in North India, this article describes how gifts that are given often critique—by obviation—those that remain ungiven: the care not provided by the Indian state for Bhopal survivors, the family members unwilling to donate blood for their transfusion-requiring relative, and so on. In this way, giving can come to look like a form of criticism. The critiques that acts of giving stage are of absences and deficits: we present cases where large paper hearts donated by survivors of the 1984 Bhopal Gas Disaster to the prime minister of India signal his lack of one, where donated human blood critiques others' unwillingness to do so, where acts of blood donation critique and protest communal violence, and where similar acts of giving over simultaneously highlight a deficit in familial affects and an attempt to resuscitate damaged relational forms. We thus illustrate how critique can operate philanthropically by way of partonomic relations between the given and not-given.

Sign in / Sign up

Export Citation Format

Share Document