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Conformal twists, Yang–Baxter <i>σ</i>-models & holographic noncommutativity
Araujo, Thiago,Bakhmatov, Ilya,Colgá,in, Eoin Ó,Sakamoto, Jun-ichi,Sheikh-Jabbari, Mohammad M,Yoshida, Kentaroh IOP 2018 JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL Vol.51 No.23
<P>Expanding upon earlier results (Araujo <I>et al</I> 2017 <I>Phys. Rev</I>. D <B>95</B> 105006), we present a compendium of <I>σ</I>-models associated with integrable deformations of AdS<SUB>5</SUB> generated by solutions to homogenous classical Yang–Baxter equation. Each example we study from four viewpoints: conformal (Drinfeld) twists, closed string gravity backgrounds, open string parameters and proposed dual noncommutative (NC) gauge theory. Irrespective of whether the deformed background is a solution to supergravity or generalized supergravity, we show that the open string metric associated with each gravity background is undeformed AdS<SUB>5</SUB> with constant open string coupling and the NC structure Θ is directly related to the conformal twist. One novel feature is that Θ exhibits ‘holographic noncommutativity’: while it may exhibit non-trivial dependence on the holographic direction, its value everywhere in the bulk is uniquely determined by its value at the boundary, thus facilitating introduction of a dual NC gauge theory. We show that the divergence of the NC structure Θ is directly related to the unimodularity of the twist. We discuss the implementation of an outer automorphism of the conformal algebra as a coordinate transformation in the AdS bulk and discuss its implications for Yang–Baxter <I>σ</I>-models and self-T-duality based on fermionic T-duality. Finally, we comment on implications of our results for the integrability of associated open strings and planar integrability of dual NC gauge theories.</P>
Araujo, T.,Ó,Colgá,in, E.,Sakamoto, J.,Sheikh-Jabbari, M. M.,Yoshida, K. Springer-Verlag 2017 The European physical journal. C, Particles and fi Vol.77 No.11
<P>We showed in previous work that for homogeneous Yang-Baxter (YB) deformations of AdS(5)xS(5) the open string metric and coupling and as a result the closed string density e-2 Phi root g remain undeformed. In this work, in addition to extending these results to the deformation associated with the modified CYBE or eta-deformation, we identify the Page forms as the open string counterpart for RR fields and demonstrate case by case that the non-zero Page forms remain invariant under YB deformations. We give a physical meaning to the Killing vector I of generalized supergravity and show for all YB deformations: (1) I appears as a current for the center of mass motion on the worldvolume of a D-brane probing the background, (2) I is equal to the divergence of the noncommutativity parameter, (3) I exhibits 'holographic' behavior where the radial component of I vanishes at the AdS boundary and (4) in pure spinor formalism I is related to a certain state in the BRST cohomology.</P>
Establishment of the Latin American Soil Information System Case Colombia - IRAKA
Araujo-Carrillo Gustavo Alfons,Martinez-Maldonado Fabio Ernes,Varon-Ramirez Viviana Marcela,Gomez-Latorre Douglas Andres,Estupinan-Casallas Jhon Mauric,Silva-Arero Elias Alexander,Gonzalez-Jaimes Edua 한국토양비료학회 2019 한국토양비료학회 학술발표회 초록집 Vol.2019 No.8
HELICOIDAL MINIMAL SURFACES IN A CONFORMALLY FLAT 3-SPACE
Araujo, Kellcio Oliveira,Cui, Ningwei,Pina, Romildo da Silva Korean Mathematical Society 2016 대한수학회보 Vol.53 No.2
In this work, we introduce the complete Riemannian manifold $\mathbb{F}_3$ which is a three-dimensional real vector space endowed with a conformally flat metric that is a solution of the Einstein equation. We obtain a second order nonlinear ordinary differential equation that characterizes the helicoidal minimal surfaces in $\mathbb{F}_3$. We show that the helicoid is a complete minimal surface in $\mathbb{F}_3$. Moreover we obtain a local solution of this differential equation which is a two-parameter family of functions ${\lambda}_h,K_2$ explicitly given by an integral and defined on an open interval. Consequently, we show that the helicoidal motion applied on the curve defined from ${\lambda}_h,K_2$ gives a two-parameter family of helicoidal minimal surfaces in $\mathbb{F}_3$.
The Development of Information Science in Ibero-America
Araujo, Carlos Alberto Avila Korea Institute of Science and Technology Informat 2019 Journal of Information Science Theory and Practice Vol.7 No.4
The purpose of this article is to problematize the existence of a possible Ibero-American informational thinking. It was initially observed that a relative absence of Ibero-America in the international presentations and mappings of information science exists. Below, the reality of the 22 countries that compose Ibero-America is discussed, a region that can be understood from a sociocultural and geopolitical perspective. Then, a mapping of the information science research in these countries is made. The main research topics found are: epistemological studies, relationships with library science, information literacy, representation and organization, bibliometric studies, information management, user studies, technological dimensions, and relationships with archival science and museum studies. Finally, a general epistemological configuration of information science is presented at a global level, highlighting the great trends of study of information that marked the decades of the 1960s and 1970s (physical model), 1980s and 1990s (cognitive model), and the 21st century (sociocultural model), and which manifested themselves in the different subareas that make up the field. The most recent research in information science, in addition to addressing information transfer (physical dimension) and its relationship with data and knowledge (cognitive dimension), has also incorporated aspects related to the social effects of information, its role in the constitution of identities and culture, and the importance of its material conformations. Such expansion reflects attempts to address the complexity of informational phenomena. Therefore, it is concluded that it is important to place the specific contributions of Ibero-America in this context.
Forced swimming stress increases natatory activity of lead-exposed mice
Araujo Ulisses C.,Krahe Thomas E.,Ribeiro-Carvalho Anderson,Gomes Regina A. A.,Lotufo Bruna M.,Moreira Maria de Fátima R.,de Abreu-Villaça Yael,Manhães Alex C.,Filgueiras Cláudio C. 한국독성학회 2021 Toxicological Research Vol.37 No.1
Recent evidence points to the relationship between lead toxicity and the function of the hypothalamic-pituitary-adrenal axis, which suggests that lead exposure could influence how an individual cope with stress. Here we test this hypothesis by investigating the behavioral effects of lead exposure in mice during the forced swimming test (FST), a parading in which animals are exposed to a stressful situation and environment. Swiss mice received either 180 ppm or 540 ppm of lead acetate (Pb) in their ad-lib water supply for 60–90 days, starting at postnatal day 30. Control (Ctrl) mice drank tap water. At the end of the exposure period, mice were submitted to a 5-min session of FST or to an open-field session of the same duration. Data from naïve animals showed that corticosterone levels were higher for animals tested in the FST compared to animals tested in the open-field. Blood-lead levels (BLL) in Pb-exposed mice ranged from 14.3 to 106.9 μg/dL. No differences were observed in spontaneous locomotion between Ctrl and Pb-exposed groups in the open-field. However, in the FST, Pb-treated mice displayed higher swimming activity than Ctrl ones and this effect was observed even for animals with BLL higher than 20 μg/ dL. Furthermore, significant differences in brain glutathione levels, used as an indicator of led toxicity, were only observed for BLL higher than 40 μg/dL. Overall, these findings suggest that swimming activity in the FST is a good indicator of lead toxicity and confirm our prediction that lead toxicity influences behavioral responses associated to stress.
Yang-Baxter σ -models, conformal twists, and noncommutative Yang-Mills theory
Araujo, T.,Bakhmatov, I.,Colgá,in, E. Ó,.,Sakamoto, J.,Sheikh-Jabbari, M. M.,Yoshida, K. American Physical Society 2017 Physical Review D Vol.95 No.10
<P>The Yang-Baxter s-model is a systematic way to generate integrable deformations of AdS(5) x S-5. We recast the deformations as seen by open strings, where the metric is undeformed AdS(5) x S-5 with constant string coupling, and all information about the deformation is encoded in the noncommutative (NC) parameter Theta. We identify the deformations of AdS(5) as twists of the conformal algebra, thus explaining the noncommutativity. We show that the unimodularity condition on gamma-matrices for supergravity solutions translates into Theta being divergence-free. Integrability of the s-model for unimodular sigma-matrices implies the existence and planar integrability of the dual NC gauge theory.</P>
Trade Restrictions in Brazil : Who Pays the Price?
( Sonia Araujo ),( Dorothee Flaig ) 세종대학교 경제통합연구소 2017 Journal of Economic Integration Vol.32 No.2
This study finds that a unilateral reduction in Brazil`s relatively high barriers to trade would increase its integration into the world economy and expand production and jobs. Using a multi-region Computable General Equilibrium model that is particularly well-suited to gauge the impact of trade policy shocks in global value chains, this study documents the effects of reducing important barriers to trade in Brazil: reducing import tariffs and local content requirements, and eliminating indirect taxes levied on exports. The largest gains in production and exports would accrue to manufacturing sectors, contradicting the widespread perception in Brazil that lifting trade protection would reduce the share of manufacturing in production. Moreover, deeper integration into global value chains would raise economic efficiency, and the higher share of foreign intermediate goods used in production would lead to lower prices, boost international competitiveness, and also benefit Brazilian households.