Scale-similar structures of homogeneous isotropic non-mirror-symmetric turbulence based on the Lagrangian closure theory

We investigate the effect of helicity on the scale-similar structures of homogeneous isotropic and non-mirror-symmetric turbulence based on the Lagrangian renormalised approximation (LRA), which is a self-consistent closure theory proposed by Kaneda (J. Fluid Mech., vol. 107, 1981, pp. 131–145). In this study, we focus on the time scale representing the scale-similar range. For the LRA, the Lagrangian two-time velocity correlation and response function determine the representative time scale. The LRA predicts that both the Lagrangian two-time velocity correlation and response function equation do not explicitly depend on helicity. We assume the extended scale-similar spectra and time scale by considering the helicity dissipation rate. Considering the small-scale structures, the requirements for the energy and helicity fluxes and response function equation to be scale similar, yield the conventional inertial-range power laws and provide the energy and helicity spectra $\propto k^{-5/3}$ and the time scale $\propto \varepsilon ^{-1/3} k^{-2/3}$ , where $\varepsilon$ and $k$ denote the energy dissipation rate and wavenumber, respectively. Notably, energy flux can be scale similar only when $k^H /k \ll 1$ , where $k^H = \varepsilon ^H/\varepsilon$ and $\varepsilon ^H$ denotes the helicity dissipation rate. This condition makes the energy cascade process in the scale-similar range completely independent of helicity. We also investigate the localness of the interscale interaction in the energy and helicity cascades for the LRA. We demonstrate that the helicity cascade is slightly non-local in scales compared with the energy cascade. This study provides a foundation on the modelling of non-mirror-symmetric turbulent flows.

Social closure and the reproduction of stratified international order

This article investigates how the means by which actors compete for position in the management of international society stratifies international order. Advancing scholarship on hierarchies, it applies a theory of social closure to examine two status groups, The Family of Civilised Nations and the G20, arguing that stratification is reproduced by a dynamic interplay of top-down collectivist exclusion on the part of superiorly positioned actors and bottom-up mimicry performed by those inferiorly positioned. As such, the same means of closure which used the Standard of Civilisation to exclude outsiders from the Family of Civilised Nations in the past stratifies non-state actors today, particularly international non-governmental organisations (INGOs) seeking to play a role in-the G20. This article offers amendments to closure theory in IR, demonstrating its utility for analysing contemporary international politics, engaging in trans-historical analysis, and in incorporating non-state actors into enquiry.

Social Life as Collective Struggle: Closure Theory and the Problem of Solidarity

In recent years, all over the globe we have seen intensifying economic exploitation, political disenfranchisement, social marginalization and cultural repression in all kinds of political regimes, from liberal democratic to authoritarian and dictatorial. Although the strategies vary with regard to regime and context, in all of them we observe that while a growing number of social groups are speaking out and rising against them, a presumably much higher number of groups do not. In this article, I argue that all these processes can be conceived as aspects of ongoing closure struggles in social life. However, in order to understand why some social groups are able to fight against closure strategies while others are not, closure theory in its current state of elaboration is not of any help. While it operates with the term solidarization, it does not offer any explanation of how such acting in solidarity may become possible in closure struggles. The article is a mainly theoretical contribution of how to solve this problem.

A closure fogalma az angolszász és a hazai szociológiában

A tanulmány célja, hogy Randall Collins A piac lezárása és a hivatások konfliktuselmélete című tanulmányának most megjelenő fordítása kapcsán betekintést nyújtson a closure fogalmának az angolszász szociológiában kialakult különböző jelentésrétegeibe, valamint, hogy bemutassa az eddigi magyar honosításra tett kísérleteket és reflektáljon a fordítás nehézségeire. Ennek érdekében először rámutat arra, hogy Max Weber Schließung fogalma jelentős változásokon esett keresztül a Gazdaság és társadalom írása közben, majd röviden bemutatja az ún. neoweberiánus closure theory keletkezési körülményeit és a kapcsolatát Weber eredeti koncepciójával. Az elmélet részletes és átfogó ismertetése helyett Frank Parkin és Raymond Murphy munkáit alapul véve a központi fogalom, a closure jelentésének gazdagodására fókuszál, csak jelezve a fogalom továbbélését és központi jelentőségét a hivatások és a professzionalizáció neoweberiánus megközelítésében. Végül áttekinti az eddigi magyar recepciót és röviden összegzi az új magyar fordítás melletti érveket.

Monopolistic professional closure, family credentials and examination procedures in the Venetian college of accountants (16th−17th century)

PurposeThe paper investigates the closure mechanisms and strategies of exclusion concerning the establishment and subsequent functioning of the Collegio dei Rasonati, the professional body of accountants that was established in Venice in 1581 and operated until the end of the 18th century.Design/methodology/approachThe research design offers a critical longitudinal explanation of the emergence of the Collegio dei Rasonati as a professional body in the context of Venetian society by relying on the social closure theory elaborated by Collins (1975); Parkin (1979) and Murphy (1988).FindingseThe Collegio dei Rasonati was established to overcome the prerogatives of a social class in accessing the accounting profession. However, the pre-existing professional elites enacted a set of social closure strategies able to transform this professional body into a stronghold of their privileges.Research limitations/implicationsAs virtually all of the evidence concerning the admission examinations has been lost over time, the investigation is restricted to the study of the few examples that have survived. The main implication of the study concerns the understanding of some dynamics leading to neutralize attempts to replace class privileges with a meritocratic system.Originality/valueThe research investigates the structure of the rules of social closure revealing the possibility of an antagonistic relationship between different co-existing forms of exclusion within the same structure. Moreover, it highlights that a form of exclusion can be made of different hierarchical levels.

A case report of triple neural tube defect: revisiting the multisite closure theory

Background Triple neural tube defects are rare. To the author’s knowledge, there are only four reported cases available in the literature up to date. Controversies exist with regards to the development of neural tube defects. We revisit the multisite closure theory and try to explain the mechanism of neural tube defects in our case. Case presentation We report a case of one-month-old baby boy who presented to us with three distinct neural tube defects. He had occipital and cervical encephaloceles along with thoracolumbar myelomeningocele accompanied by syrinx and mild hydrocephalus. All the three defects were surgically corrected with good neurological outcome. Conclusion In the multisite model of human neural tube closure, there are only two fusion sites and two neuropores unlike in mouse. This can explain the origin of open neural tube defects including anencephaly and myelomeningocele (as in our case) but cannot account for the development of encephalocele, which appears to be a post neurulation defect.