30 research outputs found
Abordaje bioquímico de alteraciones ácido-base
No full textBackground: The current paradigms in arterial blood gas analysis are based on mathematical or physicochemical models that require complex algorithms for interpretation. This leads to avoidance or dislike from health care professionals.
Purpose: To formulate a new approach to the analysis and classification of acid base disturbances.
Methodology: we conducted a systematic review of the related literature and a paradigm shift for data interpretation.
Results: Acid-base disorders can be grouped and managed according to the underlying biochemical processes.
Conclusions: This proposal represents a new classification, which groups acid base disorders according to the underlying causal biochemical process. Disorders with an elevated anion gap relate to alterations in cellular respiration (energy/ATP production)- All disturbances with normal anion gap relate to transmembrane ion exchange.Contexto: los paradigmas actuales del análisis de gasometrías sanguíneas están basados en modelos matemáticos o físico químicos que requieren algoritmos complejos de interpretación. Esto conduce a que los profesionales de salud eviten y/o rechacen el tema.
Objetivo: formular un nuevo abordaje para el análisis y clasificación de los trastornos ácido-base.
Metodología: revisión sistemática de la literatura sobre el tema y cambio en el paradigma de interpretación de los datos.
Resultados: los trastornos ácido-base pueden agruparse y manejarse de acuerdo con los procesos bioquímicos subyacentes
Conclusiones: la nueva clasificación propuesta agrupa los trastornos ácido base según el proceso bioquímico subyacente. Los trastornos que elevan la brecha aniónica corresponden a alteraciones en la respiración celular (producción de energía/ATP). Los trastornos con brecha aniónica normal corresponden a alteraciones en el intercambio transmembrana de iones
Algoritmo diagnóstico para el abordaje bioquímico de trastornos ácido-base
No full textContext: The biochemical approach to acid-base balance classifies disturbances in two categories based on cellular mechanisms. The first one being cellular respiration (ATP), which presents high anion gap and changes in carbon dioxide levels, and the second one, cellular metabolism (ion transport through membrane channels), which evidences normal anion gap and changes in other cations and anions.
Objective: To present a new diagnostic algorithm for acid-base disturbances, based on the biochemical approach.
Method: Original research with systematic analysis and data organization, following biochemical processes that affect acid-base balance.
Results: A simple, three-step algorithm which classifies information in a diagnostic table that connects blood gas analysis results (pH, anion gap or base excess, bicarbonate, carbon dioxide and unmeasured anions) with the biochemical cause and most probable clinical findings.
Conclusions: The biochemical approach is considered the new model to understand, explain and diagnose acid-base balance and disturbances. All high anion gap disturbances occur in cellular respiration, while all normal anion gap disturbances occur in membrane channel function. The diagnosis algorithm simplifies and organizes the information to describe medical conditions with data from a blood gas analysis. This approach is the first model to establish a linear correlation between lab results, biochemical cause, and clinical findings of acid-base disturbances.Contexto: el abordaje bioquímico de trastornos ácido-base clasifica las alteraciones en dos categorías basándose en mecanismos celulares. La primera categoría es la respiración celular (ATP), que presenta una brecha aniónica elevada y cambios en niveles de dióxido de carbono. La segunda, es el metabolismo celular (transporte de iones a través de canales de membrana), el cual presenta una brecha aniónica normal con cambios en otros cationes y aniones.
Objetivo: presentar un nuevo algoritmo diagnóstico para trastornos ácido-base con base en el abordaje bioquímico.
Método: investigación original con análisis sistemático y organización de datos siguiendo procesos bioquímicos que afectan el balance ácido-base.
Resultados: un algoritmo simple de tres pasos que clasifica la información en una tabla diagnóstica que conecta los resultados de gasometrías sanguíneas (pH, brecha aniónica o exceso de base, bicarbonato, dióxido de carbono y aniones no medidos) con la causa bioquímica y hallazgos clínicos más probables.
Conclusiones: el abordaje bioquímico es el nuevo modelo para entender, explicar y diagnosticar el equilibrio ácido base y sus trastornos. Todas las alteraciones que presentan brecha aniónica elevada se originan en la respiración celular, mientras que todas las que presentan brecha aniónica normal se originan en canales de membrana. El algoritmo diagnóstico simplifica y organiza la información para describir condiciones médicas desde la información de una gasometría sanguínea. El abordaje bioquímico es el primer modelo que conecta los resultados gasométricos con la causa bioquímica y los hallazgos clínicos más probables de los trastornos ácido-base
Exposiciones con niños, una experiencia aleccionadora. 51 Tercera época (2011-2012) diciembre-marzo. Gaceta de Museos. Museos y Educación
No full textÁvila, Alejandro de (2000), “Tejidos que cuidan el alma”, en Textiles de Oaxaca, núm. 35, 2da. ed. México, Artes de México.Barabas, M. Alicia y M. Bartolomé Editores (1999), Configuraciones étnicas en Oaxaca. Perspercitvas Etnográficas para las Autonomías. México, INAH-INI.Barrera, Marco (2004), “Los niños de Santa Ana, portadores de cultura”, en Museos de México y del Mundo, núm. 2. México, CONACULTA/INAH/INBA.Bedolla G. Ana (1995), “Museso comunitarios: una experiencia social”, en México en el Tiempo, núm. 6. México, México Desconocido-INAH.(2005), “Hazme si puedes… relato sobre una exposición”, en
gaceta de museos 35. México, CONACULTA/INAH.(2010), “Expriencias institucionales de vinculación”, en gaceta de museos 47-48. México, CONANCULTA/INAH.Holidohler, C y E.O. Wilson (1996), Viaje a las hormigas. Barcelona, Grijalbo.Huxley, Julián (1971) Las hormigas. Buenos Aires, Centro Editor de América Latina.Lacouture, Felipe (1989), “La nueva museología: conceptos básicos y declaraciones”, en Artes Plásticas, vol. 2, núm. 3. México, UNAM.(1996) Conferencia dictada en el Museo Nacional de Culturas
Populares. Septiembre. México.Maeterlink, Maurice (1976), La vida de las hormigas. México, Populibros LaPrensa.Vázquez Olvera, Carlos (2005), Iker Larrauri Prado. Museógrafo mexicano. México, CONACULTA/INAH.Weitlaner J., Irngard. (2000), “Anatomía de una tradición textil”, en Textiles de Oaxaca. núm. 35, 2da. Ed. México, Artes de México
Dos cartas desconocidas de Justo Lipsio, y otras seis que le atañen, en el epistolario de Lorenzo Ramírez de Prado (1583-1658)
No full textJ. SOLÍS DE LOS SANTOS: TWO UNPUBLISHED LETTERS OF JUSTUS LIPSIUS. Manuscript 2598 in the General Library of the University of Salamanca bears witness to a brief exchange of letters in the years 1604 and 1605 between Justus Lipsius (1547-1606) and two young scholars of the Salamancan circle. These letters did not appear in the edition and study of the correspondence between Lipsius and Spanish scholars published by Alejandro Ramírez, who based his work on various printed and manuscript sources, Epistolario de Justo Lipsio y los españoles (1577-1606), Madrid 1966. Nor is there any reference to them in the inventory of the correspondence of the Flemish humanist published by Aloïs Gerlo and H. D. L. Vervliet, which examined all known sources as a basis for a critical edition of the complete letters, Inventaire de la correspondance de Juste Lipse, 1564-1606, Antwerp 1968.
MS. Salamanca BU 2598 is a 198-sheet volume measuring 280 x 180 mm., with binding and folio-numbering dating from well after it was originally put together. It bears the title «Epistolario Selecto de Diversos Varones», but the original title is «Epistolae D[omini] Laurentii Ramires de Prado» (f.2r) and it came from the library of the Colegio Mayor of Cuenca (Salamanca). It was kept, with the catalogue number 906, in the Biblioteca de Palacio in Madrid until 1954, when the manuscripts from the former Salamancan Colegios Mayores which were held there were finally transferred to the University of Salamanca.
The manuscript consists of two clearly differentiated sections. The first, ff. 1-93, contains copies of 80 Latin letters by Spanish and foreign scholars. The rest, ff. 103-198, separated from the letter collection by a number of blank sheets, consists of some notes and abbreviated quotations which suggest a draft to a philological commentary. The most interesting part of the MS., the copies of the 80 letters, can be ascribed to two different 17th century hands, possibly copyists in the service of don Lorenzo Ramírez de Prado, author and addressee of the greater part of the correspondence. In contrast, the draft contained in the second part of the MS. appears to be in the hand of the owner of the codex.
The letters cover the period between September 1601 and November 1606, and most of them deal with matters of literary learning. Worthy of special mention, in addition to the 34 letters by the owner of the MS., who at this time was completing his studies in Law and Humanities at the University of Salamanca, are 2 from Justus Lipsius, 2 from José Esteve, bishop of Orihuela, 8 from Juan Luis de la Cerda, 3 from Martinus Antonius Delrius, 1 from Isaac Casaubon, 1 from Francisco Cascales, 1 from Miguel de la Cerda, 1 from Luis Carrillo y Sotomayor, 3 from Bartolomé Morlanes, 1 from Gil González Dávila and 1 from Cardinal Cesare Baronio, alongside other correspondents whose identification presents some difficulty.
Whatever the importance of these unpublished documents, they have remained practically ignored, since I have only been able to find two mentions of them.
Joaquín de Entrambasaguas, Una familia de ingenios: Los Ramírez de Prado (Madrid, 1943) 22, n. 3, cited this ms. 906, then in the Biblioteca de Palacio, when transcribing a letter from Maximilian, Duke of Bavaria, to don Alonso Ramírez de Prado, father of the manuscript’s owner and at the time Treasury councillor. This letter is on f.32v: it would therefore seem that the present page-numbering was carried out in Salamanca University Library itself. In addition, Entrambasaguas, in a note on p. 102, mentions some correspondents and announces a forthcoming critical edition of the MS., which never materialised. Gregorio de Andrés, El Maestro Baltasar de Céspedes, humanista salmantino y su Discurso de las Letras. Estudio biográfico y edición crítica (Madrid-El Escorial 1965) 176, also alludes to this ms., by then in Salamanca University Library, to support a thesis he is arguing, but without a specific reference to catalogue- or page-number to indicate the source of his information. These two cases aside, I know of no other reference or mention —far less description— of this manuscript. In my «El humanista extremeño Lorenzo Ramírez de Prado, entre Céspedes y el Brocense», La recepción de las Artes Clásicas en el siglo XVI (Cáceres 1996) 675, I advanced some information on one of the Lipsius letters, with all due caution and rigour.
Following the procedure adopted in Iusti Lipsi Epistolae (Brussels 1978-; cf. M. A. Nauwelaerts, «L’édition de la correspondance de Juste Lipse», in Acta Conventus Neo-Latini Lovaniensis [Louvain‑Munich 1973] 433-436), the copies of these letters of Lipsius can be referenced as follows:
1604 07 13 Justus Lipsius (Louvain) to Fernando Lopes de Milan (Lisboa) inc Litteris tuis, ut accepi et legi, statim c: Salamanca BU ms. 2598, ff. 22r-23r.
1605 02 03 Justus Lipsius (Louvain) to Lorenzo Ramírez de Prado (Salamanca) inc An non audacter ad me adeas, Delrio meo inducente? c: Salamanca BU ms. 2598, f. 6r.
In the first one, Justus Lipsius replies briefly (15 lines) and courteously to a consultation concerning a passage of Tacitus (Separanda Silani materna bona: Tac. Ann. 3.68.2). The original letter from Fernando de Milan is not contained in the MS. Lipsius’ reply coincides with the points subsequently developed in the first part of the commentary ad loc. contained in his posthumous edition. He congratulates his correspondent on having undertaken a translation of Tacitus into Portuguese and invites him to consult him on further doubts. Of this translation and author there is not the slightest trace in the catalogue by Diego Barbosa Machado, Bibliotheca Lusitana historica, critica e cronologica, I-IV (Lisbon 1741-1759).
The second letter is a 24-line reply to one sent to him by the young Lorenzo Ramírez. Lipsius expresses his satisfaction at his correspondent’s having established a friendship with his own old friend Delrius. Martinus Antonius Delrius (Antwerp 1551, Louvain 1608) had been teaching Sacred Scripture at the University of Salamanca since 1603. In a letter written to Delrius on the same day, 1605 02 03 (cf. Gerlo & Vervliet, Inventaire, p. 379), we learn that Lipsius wrote to a Spaniard named Ramirezius («Sed heus Ramirezius ille egregius: & scripsi»), who is not identified by A. Ramírez, Epistolario de Justo Lipsio y los españoles, 176, n. 245. In this ignored letter, Lipsius thanks Lorenzo Ramírez for his gift of the book by Sanctus Orientius and promises to look out some notes on Martial which he previously used with Raderus, that is, Matthaeus Rader, S. I. (Inichingen 1561, Munich 1634), for the commentary which Lorenzo Ramírez was preparing. In fact, the publication of the second edition of Sancti Orientii episcopi Illiberitani Commonitorium, iterum emendatum ac notis secundis illustratum a Martino Delrio (Salamanca: A. Taberniel, 1604; first edited by Delrius himself: Antwerp 1600), was financed by Lorenzo Ramírez, who wrote a short prologue dated XV. Kal. Octobreis MDCIV. On the other hand, the commentary on Martial was published under the title: HYPOMNEMATA AD LIB. SPECTACVLORVM ET QVATVOR PRIMOS EPIGRAMMATΩN M. Valerii Martialis, collecta ex schedis succisivis Domini Laurentii Ramirez de Prado, which were included in the edition of the complete text in: M. VALERII MARTIALIS EPIGRAMMATVM LIBRI XV (Paris: Michaelis Sonnius, 1607). For the controversy aroused by this commentary, cf. F. R. Hausmann, «Martialis, M. Valerius», in F. E. Cranz, V. Brown, P. O. Kristeller, eds., Catalogus translationum et commentariorum, IV (Washington 1980) 249-296.
Finally, Lipsius also returns to the interpretation of the same passage of Tacitus, this time with reference to the phrase: quippe alia parente geniti. Lorenzo Ramírez proposed the reading quippe alta parente geniti. Lipsius would rather have another expression (Tuum non sperno si dixisset expressius: tali aut illâ parente geniti).
All of these proposed readings are to be found in the above-mentioned commentary in the posthumous edition of 1607, including the suggestion alta parente which Lipsius claims to have been sent by a certain scholar from Spain:
Scripsit ad me ex Hispania vir doctus, in veteri libro se legisse: quippe alta parente. quod ad nostrum illum sensum faciat, sed mallem aliud verbi. (C. Cornelii Taciti Opera quae exstant. Iustus Lipsius postremum recensuit [Antwerp 1607] 100-101, n. 169).
Jozef Ruysschaert, Juste Lipse et les Annales de Tacite: une méthode de critique textuelle au XVIe siècle (Turnhout 1949) 179, n. 4, echoed this critical commentary in his important study (alia (M); C07: tali ou illa «[vir doctus ex Hispania : alta]»), and also observes, in connection with this vir doctus ex Hispania: “Il s’agit sans doute de M. Sarmiento de Mendoza”. Now, however, with these new letters of Lipsius which I have published in due course, «Dos cartas desconocidas de Justo Lipsio, y otras seis que le atañen, en el epistolario de Lorenzo Ramírez de Prado (1583-1658)», Humanistica Lovaniensia 47 (1998) 278-331, we have evidence that the vir doctus who had sent him the reading alta parente from Spain was in fact Lorenzo Ramírez de Prado. (Translation by J. J. Zoltowski)
Wettability and microstructural evolution of copper filler in W and EUROFER brazed joints
No full textOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.In terms of wettability, active systems are characterized by a reduction in interfacial energy as the time at specific conditions is increased. This article aims to investigate the evolution of wettability and microstructure, which undergoes a critical transformation at temperatures and dwell times near brazing conditions due to their significant impact on resultant mechanical properties. The objective is to enhance wettability and prevent the formation of different phases that can occur rapidly within the brazing window conditions. Up to 1105 °C, complete fusion of the filler does not occur. However, once it happens, the expansion of the copper filler in EUROFER increases up to 400%, and the contact angle reduces from 100° to 10°, indicating an active wetting behavior. On the other hand, when copper is used with tungsten, an inert behavior is observed, maintaining the contact angle around 70°. Brazed joints carried out under the most promising wetting conditions demonstrated that at 1110 °C-1 min, various phenomena began to occur. This includes solid-state diffusion of copper in the EUROFER, following the austenitic grain boundaries, and partial dissolution of Fe in the copper braze. Increasing the brazing time from 2 to 5 min achieved high interfacial adhesion properties and controlled the diffusion layer and Fe-rich band formed at the W-braze interface, resulting in the best mechanical results (295 MPa)
A Paisagem da sarabanda infernal águas-fortes goyescas de R. Arlt
No full textTese (doutorado)- Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Literatura, Florianópolis, 2011Roberto Arlt escreveu suas crônicas em El Mundo (Buenos Aires) entre os anos de 1928 e 1942. O título que as consagrou, aguafuertes porteñas, remete a uma técnica de gravura que se realiza pela inscrição sobre uma placa de metal e pela submersão dessa placa em ácido nítrico. Um dos pontos de partida da pesquisa foi o questionamento sobre a escolha da água-forte para denominá-las e a hipótese mais relevante é a de que a linguagem sarcástica e abjeta de seu narrador age como o ácido nítrico sobre o papel, dando relevo a um espetáculo brutal que provoca e corrói o espaço do jornal em que se inscrevem. Em momentos esparsos, Arlt irá mencionar o qualificativo goyesco para caracterizar suas águas-fortes e um segundo ponto de partida foi pensar o que as definiria como tal. Investiguei a hipótese de que o Goya resgatado por Arlt é o gravurista sardônico destacado por Charles Baudelaire em sua leitura de Goya. De modo que, para entender o Goya de Arlt, procuro o Goya de Baudelaire e aquele apreciado por artistas como Facio Hebequer e Adolfo Bellocq, gravuristas cujas criações foram fortemente marcadas pelos traços grotescos dos Caprichos e Disparates do pintor. Finalmente, o goyesco nas crônicas de Arlt conduz a suas percepções da modernidade, que ganham o tom esquivo da modernidade de Baudelaire, que é paixão e calvário, encantamento pelo novo e penúria por sua infâmia. Nesse embate, o que quero apresentar é a fissura aberta pelas imagens expostas de modo sarcástico nas águas-fortes goyescas de Arlt na linearidade progressiva da construção do homem e do Estado modernos, algo como o assombro que se nos apresenta na série de gravuras dos Desastres da Guerra
Author Correction: A consensus protocol for functional connectivity analysis in the rat brain
No full textAuthor Correction: A consensus protocol for functional connectivity analysis in the rat brai
Development of flexible filler ribbons by melt spinning for joining W to CuCrZr material for heat sink application
No full textThis work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. The authors would also like to acknowledge the Community of Madrid in the framework of the Multiannual Agreement with the Rey Juan Carlos University in line of action 1, “Encouragement of Young Phd student's investigation" Project Ref. M 2168 Acronym DARUCEF. D. Salazar acknowledge support from the EU Horizon 2020 research and innovation programme under Grant Agreement No. 862617 – Multi-Fun.This paper studies the use of the melt-spinning technique as an alternative filler fabrication route to obtain
flexible 80Cu-20Ti ribbons, which presents flexible and adaptability properties to cover the divertor or first wall
pipe in future fusion reactors. The results showed that best conditions are achieved using a 0.8 mm diameter of
the nozzle and 30 m/s of the linear wheel-speed. This condition allows to change the microstructure of the
fabricated ribbons giving rise to a lower Cu4Ti intermetallic phase formation enhancing the adaptability properties. Ribbon dimensions are high enough to cover the perimeter of the pipe. Best conditions were selected to
use as filler material in W-CuCrZr brazed joints at 960 ◦C. The results showed the consecution of high metallic
continuity interfaces. Besides, the selected brazing conditions did not cause any thermal effect in the W base
material but caused a softening effect in the CuCrZr base material as a consequence of the coarsening process of
the hardening precipitates
Modelo de implantação de informática na educação segundo uma visão sistêmica apoiada na gestão de mudanças
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.O CGI (Comitê Gestor da Internet no Brasil) (2006), PNAD (Pesquisa Nacional por Amostras de Domicílios) (2005) e Censo Escolar (2005) apontam para uma realidade onde, apesar dos recentes esforços de vários governos, aproximadamente, 54% da população brasileira nunca usou um computador e 67% nunca navegou na Internet. Apenas 19% dos domicílios possuem computador e somente 25% das escolas básicas possuem computadores ligados à Internet. A situação é ainda mais grave quando se identifica que, mesmo nas escolas com conexão e computadores, muitas das salas de informática ficam trancadas e tornam-se alvo de sucateamento e furto de equipamentos, em geral, pela falta de formação dos professores ou pela ausência de uma política educacional que pressuponha as tecnologias de informação e comunicação (TIC ) como instrumento pedagógico. A democratização do acesso aos produtos tecnológicos e a inclusão digital é um desafio para a sociedade atual e requer esforços e mudanças na área educacional. Este trabalho visa o desenvolvimento e experimentação de um modelo sistêmico de informatização educacional de escolas, que enfatize a implantação da informática educacional em uma abordagem de gestão de mudança, através de ações voltadas ao contexto especifico do ambiente de atuação, de maneira a gerir e integrar aspectos sociais, gerenciais e tecnológicos que contribuam, direta e indiretamente, para a mudança desejada. Nesse processo de integração, a estratégia de incorporação tecnológica leva em conta a visão social da organização, evidenciando o entendimento da escola como um sistema sócio-técnico. Nesta visão, é através da integração dos elementos da comunidade escolar que se viabiliza que as TIC consigam adquirir um estatuto de instrumento educacional, sendo internalizadas pelos atores do processo ensino-aprendizagem. Neste modelo, o enfoque sistêmico, pressupõe uma constante validação e atualização (auto-regulação), onde é possível recuperar defasagens oriundas de momentos anteriores do processo através de um constante feedback. O modelo e as nuances permitem balizar decisões no momento de definição, implantação, acompanhamento e repetição do processo. The CGI (Brazil Internet Management Committee) (2006), PNAD (National Research for Sample Home) (2005) e School Census (2005) point to a reality where, although the recent efforts of some governments, 54% of Brazilian people never used a computer and 67% never accessed the Internet. Only 19% of the homes have a computer and only 25% of the basic schools have computer with access to the Internet. The situation is even more serious when is identified that even in the schools with connection and computers, many of the computer rooms are locked and become target of trashing and equipment robery, usually, because the lack of formation of the teachers or the absence of educational politics that understand the technologies of computer science and communication as a pedagogical instrument. The democratization of the access to the technological products and the digital inclusion are a challenge to the current society and require efforts and changes in the educational area. This work aims at the development and experimentation of a systemic model of educational computerization of schools, that emphasizes the implantation of educational computer science in focus of change management, through actions faced to the specific context of the working environment, in way to manage and integrate social aspects, managemental and technological, that contribute direct and indirect ways, to the desired change. In this process of integration, the strategy of technological incorporation care about the social vision of the organization, evidencing the understanding of the school as a system partner-technician. In this vision, it is through the integration of the elements of the school community that makes possible that the technologies of computer science and communication achieve a statute of educational instrument, being internalized for the actors of the process teach-learning. In this model, the systemic approach, estimates a constant validation and update (self-regulation), where is possible to recover from imbalance derived from previous moments of the process through a constant feedback. The model and its variables allow to demarcate decisions in the definition moment, implantation, accompaniment and repetition of the process
Author Correction: Brain clocks capture diversity and disparities in aging and dementia across geographically diverse populations
No full textHerrera, Eduar; Yerlikaya, Deniz; Hu, Kun; Parra, Mario; Reyes, Pablo; García, Adolfo; Custodio, Nilton; Cardona, Juan; Barttfeld, Pablo; Brusco, Ignacio; Bruno, Martín; Ana, Sosa; Pina, Stefanie; Takada; Leonel; Resende, Elisa; Possin, Katherine; de Oliveira, Maira; Lopez, Alejandro; Lawlor, Brian; Robertson, Ian; Kosik, Kenneth; Duran, Claudia; Valcour, Victor; Yokoyama, Jennifer; Miller, Bruce; Ibanez, Agustin.Los relojes cerebrales capturan la diversidad y las disparidades en el envejecimiento y la demencia en poblaciones geográficamente diversas.
Brain clocks capture diversity and disparities in aging and dementia across geographically diverse populations.
Brain clocks, which quantify discrepancies between brain age and chronological age, hold promise for understanding brain health and disease. However, the impact of diversity (including geographical, socioeconomic, sociodemographic, sex and neurodegeneration) on the brain-age gap is unknown. We analyzed datasets from 5,306 participants across 15 countries (7 Latin American and Caribbean countries (LAC) and 8 non-LAC countries). Based on higher-order interactions, we developed a brain-age gap deep learning architecture for functional magnetic resonance imaging (2,953) and electroencephalography (2,353). The datasets comprised healthy controls and individuals with mild cognitive impairment, Alzheimer disease and behavioral variant frontotemporal dementia. LAC models evidenced older brain ages (functional magnetic resonance imaging: mean directional error = 5.60, root mean square error (r.m.s.e.) = 11.91; electroencephalography: mean directional error = 5.34, r.m.s.e. = 9.82) associated with frontoposterior networks compared with non-LAC models. Structural socioeconomic inequality, pollution and health disparities were influential predictors of increased brain-age gaps, especially in LAC (R² = 0.37, F² = 0.59, r.m.s.e. = 6.9). An ascending brain-age gap from healthy controls to mild cognitive impairment to Alzheimer disease was found. In LAC, we observed larger brain-age gaps in females in control and Alzheimer disease groups compared with the respective males. The results were not explained by variations in signal quality, demographics or acquisition methods. These findings provide a quantitative framework capturing the diversity of accelerated brain aging.Versión Publicad
