Hace tan solo unos ciento sesenta años que la denominada cultura olmeca salió a la luz. En la historia de la definición de su estilo artístico ocupa un lugar destacado el artista mexicano Miguel Covarrubias. En el artículo realizamos un análisis pormenorizado de su obra, intentando mostrar la evolución de sus ideas artísticas y la importancia que tuvieron a la hora de configurar lo que hoy se denomina «estética olmeca». Se analizan sus presupuestos teóricos y la enorme influencia que sus (...) tesis tienen, aun hoy, a la hora de analizar la que muchos consideran la «cultura madre» de Mesoamérica. (shrink)

El siguiente monográfico sobre Perú acoge diferentes reflexiones y aportaciones de un total de nueve trabajos que buscan problematizar y arrojar luz sobre algunos aspectos que han acompañado al proceso de construcción democrática que el país ha venido experimentando desde 1980. Como otros escenarios de la región, la democracia se erige tras décadas convulsas para un sistema político cooptado por elites caudillistas, encono político, intromisión militar y condiciones estructurales irresolutas. Este conjunto de factores, inscritos en un contexto de guerra fría, (...) y al albor de la revolución cubana, inspiró movimientos guerrilleros a inicios de los sesenta, como el Ejército de Liberación Nacional o el Movimiento de Izquierda Revolucionaria. Su escasa relevancia nada tendría que ver con la fuerza disruptiva que experimentaría el Partido Comunista del Perú - Sendero Luminoso. Un grupo armado de marcada impronta maoísta que, si bien hunde sus raíces en la ruptura sino-soviética de 1962, construye sus fundamentos ideológicos y sus bases revolucionarias durante la década de los setenta. (shrink)

IntroductionThe prefrontal cortex plays a crucial role in cognition, particularly in executive functions. Cortical reactivity measured with Transcranial Magnetic Stimulation combined with Electroencephalography is altered in pathological conditions, and it may also be a marker of cognitive status in middle-aged adults. In this study, we investigated the associations between cognitive measures and TMS evoked EEG reactivity and explored whether the effects of this relationship were related to neurofilament light chain levels, a marker of neuroaxonal damage.MethodsFifty two healthy middle-aged adults from (...) the Barcelona Brain Health Initiative cohort underwent TMS-EEG, a comprehensive neuropsychological assessment, and a blood test for NfL levels. Global and Local Mean-Field Power, two measures of cortical reactivity, were quantified after left prefrontal cortex stimulation, and cognition was set as the outcome of the regression analysis. The left inferior parietal lobe was used as a control stimulation condition.ResultsLocal reactivity was significantly associated with working memory and reasoning only after L-PFC stimulation. No associations were found between NfL and cognition. These specific associations were independent of the status of neuroaxonal damage indexed by the NfL biomarker and remained after adjusting for age, biological sex, and education.ConclusionOur results demonstrate that TMS evoked EEG reactivity at the L-PFC, but not the L-IPL, is related to the cognitive status of middle-aged individuals and independent of NfL levels, and may become a valuable biomarker of frontal lobe-associated cognitive function. (shrink)

¿Quiénes son los laicos en la Iglesia? ¿Encajan en la estructura de la vida religiosa? Este artículo intenta responder a estas preguntas analizando el significado como la teoría y connotaciones prácticas de los legos para la vida del Inspectoría Salesiana de Córdoba (España) después del Concilio.

Un análisis crítico del discurso informativo en los medios de comunicación a nivel internacional, lleva al autor a recurrir a tres pensadores: Aristóteles, Nietzsche y Fichte para, a través de una interpretación de tres grandes obras, promover una fundamentación, marcando unos límites, de las ciencias de la información. La Retórica, la Gaya Ciencia y la Doctrina de la Ciencia, aportan unas nuevas funciones a la técnica de informar, secuestrada globalmente por el poder, en una lucha por el control de la (...) economía mundial. La información, rescatada como discurso de las manos del poder, puede producir, entonces, receptores activos en el mensaje de actualidad, siempre que ofrezca distintas interpretaciones de los hechos de opinión en el proceso de formación de la opinión pública. (shrink)

Imagine the following situation: 11 members of a committee must vote for either candidate A or B. The members vote and candidate B loses 6-5. Now imagine a different situation where candidate B als...

We propose a mathematical model for a class of predator–prey systems more complex than the usual one, involving a commensalism effect consisting in an influence of the predator on the sustainability of the prey. This effect induces interesting new features, including bi-stability. The question of the possibility of reaching a certain attractor starting from initial conditions with a small population of predators, which presents an interest from the vewpoint of the onset of the predator in evolution, is addressed. We propose (...) two possibilities: the classical one involving adapted conditions in the far past and a new one using biodiversity, specifically the presence of another predator which operates as a starter, being displaced in the sequel. (shrink)

In the framework of population dynamics, we start from the logistic equation describing the evolution of one species with limited food supply. A split device allows us to consider the population as two sub-populations x and y evolving analogously. The dynamical system has a one-parameter family of equilibria which is structurally unstable. Then small perturbations of the system (describing functional or ethological differentiations between the sub-species) lead in general to a new system involving a fast and a slow dynamics with (...) a finite number of equilibria. In simple situations where the differentiation is clearly either an advantage or an inconvenience for one of the subspecies, the stable equilibrium amounts to extinction of the disadvantaged subspecies (elementary Darwinism). Oppositely more complex differentiations (involving both advantages and inconveniences) often lead to stable equilibria with well-defined non zero proportions of the sub-populations (preservation of the biodiversity). Other examples are concerned with symbiosis-like differentiations, leading to preservation, whereas the opposite case (mutual nuisances) has an unstable equilibrium and lead to extinction of one or the other subspecies according to the initial conditions. The case of a scission into three subspecies is more rich in consequences. In certain cases, predator-prey relations lead to auto-organization phenomena with stable diversity-preserving diversity. Cases of instability are also possible, leading to orbits tending towards a poly-cycle.This implies some kind of pseudo-extinction: this amounts to “pseudo-periodic-like” orbits with “pseudo-periods” larger and larger, tending to infinity; each pseudo-period contains parts where one of the sub-populations practically vanish. Other non-linear perturbations lead to stable orbits. (shrink)

New aspects of spectral fluctuations of (quantum) chaotic and diffusive systems are considered, namely autocorrelations of the spacing between consecutive levels or spacing autocovariances. They can be viewed as a discretized two point correlation function. Their behavior results from two different contributions. One corresponds to (universal) random matrix eigenvalue fluctuations, the other to diffusive or chaotic characteristics of the corresponding classical motion. A closed formula expressing spacing autocovariances in terms of classical dynamical zeta functions, including the Perron–Frobenius operator, is derived. (...) It leads to a simple interpretation in terms of classical resonances. The theory is applied to zeros of the Riemann zeta function. A striking correspondence between the associated classical dynamical zeta functions and the Riemann zeta itself is found. This induces a resurgence phenomenon where the lowest Riemann zeros appear replicated an infinite number of times as resonances and sub-resonances in the spacing autocovariances. The theoretical results are confirmed by existing “data.” The present work further extends the already well known semiclassical interpretation of properties of Riemann zeros. (shrink)

Justo antes de la pandemia por COVID-19, la Organización Mundial de la Salud definió unas prioridades de trabajo para la década 2020-2030. Un grupo interdisciplinario de profesionales de la salud reflexiona sobre estas prioridades, determinando unas categorías de análisis y, desde una perspectiva bioética, analiza cada una de ellas, ve su pertinencia, algunos eventos causales, las implicaciones que pueden tener si no son enfrentadas adecuadamente y hace sugerencias sobre la forma de llevarlas a cabo. En esta primera entrega se analiza (...) el primer grupo de prioridades estratégicas: “poblaciones más sanas”. En las conclusiones se destaca la conveniencia de acometer cada una de ellas de una manera colaborativa, gubernamental y privada; de reestructurar el sector salud con base en estas prioridades, aprovechando la experiencia obtenida en la lucha contra el COVID-19. La relación del ser humano con el medio ambiente también debe cambiar, apelando a la responsabilidad humana por el cuidado del planeta. (shrink)

The aim of this research was to establish linear relations (association and prediction) and inferential relations between three constructs at different levels of psychological research –executive dysfunction(microanalysis),self-regulation(molecular level), andself-vs.external regulation(molar level), in the prediction of emotion regulation difficulties. We hypothesized that personal and contextual regulatory factors would be negatively related to levels of executive dysfunction and emotion regulation difficulties; by way of complement, non-regulatory and dysregulatory personal, and contextual factors would be positively related to these same difficulties. To establish relationships, (...) we used a retrospective,ex postfacto design, where 298 university students voluntarily participated by completing standardized self-reports. Linear and structural correlational, predictive analyses were performed, as well as inferential analyses. Results were consistent and validated the proposed hypotheses, for both association and prediction. The most important result refers to the discriminant value of the five-level combination heuristic for predicting Executive Function and External (contextual) Dys-Regulation. In conclusion: (1) both personal and contextual regulation factors must be analyzed in order to better understand the variation in executive functions and emotion regulation difficulties; (2) it is important to continue connecting the different levels of the constructs referring to self-regulation, given their complementary role in the behavioral analysis of regulation difficulties. (shrink)