Search results for "transformation"
showing 10 items of 1634 documents
Spin Chains with Non-Diagonal Boundaries and Trigonometric SOS Model with Reflecting End
2011
In this paper we consider two a priori very different problems: construction of the eigenstates of the spin chains with non parallel boundary magnetic fields and computation of the partition function for the trigonometric solid-on-solid (SOS) model with one reflecting end and domain wall boundary conditions. We show that these two problems are related through a gauge transformation (so-called vertex-face transformation) and can be solved using the same dynamical reflection algebras.
External derivations of internal groupoids
2008
If His a G-crossed module, the set of derivations of Gin H is a monoid under the Whitehead product of derivations. We interpret the Whitehead product using the correspondence between crossed modules and internal groupoids in the category of groups. Working in the general context of internal groupoids in a finitely complete category, we relate derivations to holomorphisms, translations, affine transformations, and to the embedding category of a groupoid. (C) 2007 Elsevier B.V. All rights reserved.
Euclidean geometry and physical space
2006
It takes a good deal of historical imagination to picture the kinds of debates that accompanied the slow process, which ultimately led to the acceptance of non-Euclidean geometries little more than a century ago. The difficulty stems mainly from our tendency to think of geometry as a branch of pure mathematics rather than as a science with deep empirical roots, the oldest natural science so to speak. For many of us, there is a natural tendency to think of geometry in idealized, Platonic terms. So to gain a sense of how late nineteenth-century authorities debated over the true geometry of physical space, it may help to remember the etymological roots of geometry: “geo” plus “metria” literall…
Palaeogenomics of Upper Palaeolithic to Neolithic European hunter-gatherers
2023
Acknowledgements: The authors thank G. Marciani and O. Jöris for comments on archaeology; C. Jeong, M. Spyrou and K. Prüfer for comments on genetics; M. O’Reilly for graphical support for Fig. 5 and Extended Data Fig. 9; the entire IT and laboratory teams at the Department of Archaeogenetics of MPI-SHH for technical assistance; M. Meyer and S. Nagel for support with single-stranded library preparation; K. Post, P. van Es, J. Glimmerveen, M. Medendorp, M. Sier, S. Dikstra, M. Dikstra, R. van Eerden, D. Duineveld and A. Hoekman for providing access to human specimens from the North Sea (The Netherlands); M. D. Garralda and A. Estalrrich for providing access to human specimens from La Riera (S…
Lorentz invariance and gauge equivariance
2014
Trying to place Lorentz and gauge transformations on the same foundation, it turns out that the first one generates invariance, the second one equivariance, at least for the abelian case. This similarity is not a hypothesis but is supported by and a consequence of the path integral formalism in quantum field theory.
Historical Origins of the nine-point conic -- The Contribution of Eugenio Beltrami
2020
In this paper, we examine the evolution of a specific mathematical problem, i.e. the nine-point conic, a generalisation of the nine-point circle due to Steiner. We will follow this evolution from Steiner to the Neapolitan school (Trudi and Battaglini) and finally to the contribution of Beltrami that closed this journey, at least from a mathematical point of view (scholars of elementary geometry, in fact, will continue to resume the problem from the second half of the 19th to the beginning of the 20th century). We believe that such evolution may indicate the steady development of the mathematical methods from Euclidean metric to projective, and finally, with Beltrami, with the use of quadrat…
Some topological properties of the Inverse Lens Mapping
2011
Away from critical curves, lens mapping can be seen as a linear invertible transformation of the plane even for regions (cells) of relatively large size. However, close to critical curves the departures from linearity can be very strong. We discuss the topological problems induced by the mapping of regions of the image plane that include critical curves (critical cells).
La rete mediterranea della devozione. Le teresiane della provincia di Napoli
2015
Riassunto: Filo conduttore del saggio è la vita di madre Serafina di Dio, carismatica caprese fondatrice, nel secolo XVII, di sette congregazioni femminili ispirate alla spiritualità teresiana. L’affiliazione alla santa di Avila e l’adesione alla matrice della sua riforma hanno consentito alle nuove comunità devote nate da un’iniziativa periferica di collocarsi nell’alveo della Chiesa nella prospettiva istituzionale della trasformazione in monasteri di clausura.Due i focus della ricerca. Da un lato ci si è soffermati sull’omogeneità organizzativa e spirituale dei conservatori garantita da reti devozionali saldamente dipendenti dal carisma della fondatrice secondo un meccanismo nel quale res…
Key CDO functions for successful digital transformation: Insights from a Delphi study
2022
Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Given that the Chief Digital Office (CDO) is a new business position, it is not yet clear what the key functions they must develop to successfully undertake the company digital transformation process. Although previous literature has tentatively covered this issue, there are still gaps in knowledge about which functions are truly relevant. The aim of this paper is to fill this gap by (1) clarifying the key CDO functions through a Delphi study, validated by a digital dynamic capabilities (DDC) framework (Warner and Wäger 2019), and (2) presenting a measurement instrument useful for assessing the degree of the key CDO fu…
MYC Activates Stem-like Cell Potential in Hepatocarcinoma by a p53-Dependent Mechanism
2014
Activation of c-MYC is an oncogenic hallmark of many cancers including liver cancer, and is associated with a variety of adverse prognostic characteristics. Despite a causative role during malignant transformation and progression in hepatocarcinogenesis, consequences of c-MYC activation for the biology of hepatic cancer stem cells (CSCs) are undefined. Here, distinct levels of c-MYC over-expression were established by using two dose-dependent tetracycline inducible systems in 4 hepatoma cell lines with different p53 mutational status. The CSCs were evaluated using side-population approach as well as standard in vitro and in vivo assays. Functional repression of p53 was achieved by lentivira…