La pandemia de Covid-19 cambió la forma de manejar los laboratorios de ingeniería. Para el último trimestre del año 2020, se estableció como un objetivo académico el desarrollo de prácticas del Laboratorio de Procesos virtuales involucrando a estudiantes de pregrado de Ingeniería Química de la Universidad Metropolitana, utilizando la plataforma de programación y cálculo numérico Matlab aplicando la metodología de estudio Aprendizaje Basado en Proyectos. La respuesta de los estudiantes indicó que la experiencia adquirida les genera confianza en su uso, (...) mejor comprensión de las ventajas y desventajas involucradas y a futuro un beneficio competitivo en la industria. (shrink)

Se presenta las aplicaciones desarrollas para virtualizar el laboratorio de fluidos y transferencias de la Universidad Metropolitana. El objetivo es permitir a los estudiantes realizar las prácticas de laboratorio de manera online. Se desarrolló una aplicación de cada práctica utilizando MATLAB App Designer. Los estudiantes lograron hacer cada práctica virtual manipulando en tiempo real las variables correspondientes y obtener los resultados con el cual realizar los informes. Estas aplicaciones fueron empleadas para dictar la asignatura de manera virtual, obteniendo buena aceptación (...) por parte de los estudiantes, los cuales sintieron cada práctica interactiva y de utilidad para su proceso de aprendizaje. (shrink)

BackgroundMonitoring recovery–stress balance in sport is becoming more relevant to prevent training maladaptation and reach the optimal performance for each athlete. The use of questionnaires that identify the athlete’s recovery–stress state have much acceptance in sports due to reliability and useful, furthermore for its low cost. Identifying possible differences between sport modalities and sex is important to determine specific needs and possible intervention ways to keep a recovery–stress balance. The aim was to analyze the differences in the recovery–stress state and (...) mood states by sex and sport type during the competitive phase in young Mexican athletes. As a secondary objective, the psychometric properties of the Mexican version of the Recovery–Stress Questionnaire for Athletes were analyzed.MethodsA cross-sectional study was carried on with 461 athletes, 17.95 years old, from six sports disciplines. The RESTQ-Sport and Profile of Mood States were applied in a single moment. Differences by sex and sports modality were analyzed. RESTQ-Sport’s confirmatory factor analysis was performed after the stress and recovery theoretical structure of two stress and two recovery dimensions, and last, the concurrent validation with the POMS was carried on.ResultsSignificant differences by sex were found in the General Recovery and Sport Stress dimensions of the RESTQ-Sport as well as Vigor factor of the POMS, being higher for men; furthermore, both the Sport Recovery dimension of RESTQ-Sport and Cholera and the Fatigue and Depression factors from POMS also had differences by sport type, showing a less recovery and high stress for individual sport athletes. Goodness-of-fit indexes of the model for the RESTQ-Sport were acceptable. Pearson’s correlation between questionnaires was moderate.ConclusionThe recovery–stress state shows differences in the function of sex and sport modality. More special attention is suggested for women and individual sport athletes. The higher punctuation for men compared with women in sport stress dimension did not negatively affect the recovery–stress balance for male athletes. Finally, the Mexican context adaptation of the RESTQ-Sport provides a psychometric instrument suitable to assess the recovery–stress balance in Mexican athletes. (shrink)

IntroductionRheumatologists are the primary healthcare professionals responsible for patients with rheumatic diseases and should acquire medical ethical competencies, such as the informed consent process. The objective clinical structured examination is a valuable tool for assessing clinical competencies. We report the performance of 90 rheumatologist trainees participating in a station designed to evaluate the ICP during the 2018 and 2019 national accreditations.MethodsThe station was validated and represented a medical encounter in which the rheumatologist informed a patient with systemic lupus erythematosus with (...) clinically active nephritis about renal biopsy. A trained patient–actor and an evaluator were instructed to assess ICP skills in obtaining formal informed consent, delivering bad news and overall communication with patients. The evaluator used a tailored checklist and form.ResultsCandidate performance varied with ICP content and was superior for potential benefit information but significantly reduced for potential complications and biopsy description. Only 17.8% of the candidates mentioned the legal perspective of ICP. Death was omitted by the majority of the candidates ; after the patient–actor challenged candidates, only 57.1% of them gave a clear and positive answer. Evaluators frequently rated candidate communications skills as superior, but ≥1 negative aspect was identified in 69% of the candidates.ConclusionsEthical competencies are mandatory for professional rheumatologists. It seems necessary to include an ethics competency framework in the curriculum throughout the rheumatology residency. (shrink)

In memoriam José Arrazola Ramírez The logic $\textbf{G}^{\prime}_3$ was introduced by Osorio et al. in 2008; it is a three-valued logic, closely related to the paraconsistent logic $\textbf{CG}^{\prime}_3$ introduced by Osorio et al. in 2014. The logic $\textbf{CG}^{\prime}_3$ is defined in terms of a multi-valued semantics and has the property that each theorem in $\textbf{G}^{\prime}_3$ is a theorem in $\textbf{CG}^{\prime}_3$. Kripke-type semantics has been given to $\textbf{CG}^{\prime}_3$ in two different ways by Borja et al. in 2016. In this work, we (...) continue the study of $\textbf{CG}^{\prime}_3$, obtaining a Hilbert-type axiomatic system and proving a soundness and completeness theorem for this logic. (shrink)

Genuine Paraconsistent logics \ and \ were defined in 2016 by Béziau et al, including only three logical connectives, namely, negation disjunction and conjunction. Afterwards in 2017 Hernández-Tello et al, provide implications for both logics and define the logics \ and \. In this work we continue the study of these logics, providing sound and complete Hilbert-type axiomatic systems for each logic. We prove among other properties that \ and \ satisfy a restricted version of the Substitution Theorem, and (...) that both of them are maximal with respect to Classical Propositional Logic. To conclude we make some comparisons between \ and \ and among other logics, for instance \ and some \s. (shrink)

Lower extremity non-contact soft tissue injuries are prevalent in elite futsal. The purpose of this study was to develop robust screening models based on pre-season measures obtained from questionnaires and field-based tests to prospectively predict LE-ST injuries after having applied a range of supervised Machine Learning techniques. One hundred and thirty-nine elite futsal players underwent a pre-season screening evaluation that included individual characteristics; measures related to sleep quality, athlete burnout, psychological characteristics related to sport performance and self-reported perception of chronic (...) ankle instability. A number of neuromuscular performance measures obtained through three field-based tests [isometric hip strength, dynamic postural control and lower extremity joints range of motion ] were also recorded. Injury incidence was monitored over one competitive season. There were 25 LE-ST injuries. Only those groups of measures from two of the field-based tests, as independent data sets, were able to build robust models [area under the receiver operating characteristic curve score ≥0.7] to identify elite futsal players at risk of sustaining a LE-ST injury. Unlike the measures obtained from the five questionnaires selected, the neuromuscular performance measures did build robust prediction models. The inclusion in the same data set of the measures recorded from all the questionnaires and field-based tests did not result in models with significantly higher performance scores. The model generated by the UnderBagging technique with a cost-sensitive SMO as the base classifier and using only four ROM measures reported the best prediction performance scores. The models developed might help coaches, physical trainers and medical practitioners in the decision-making process for injury prevention in futsal. (shrink)

En años recientes la educación universitaria se ha transformado rápidamente, el desempeño de los estudiantes, los avances tecnológicos y la pandemia, han generado nuevos retos. El aprendizaje adaptativo es una alternativa que se puede implementar para identificar las fortalezas y debilidades académicas y junto con las Tecnologías de la Información aplicadas a la educación es posible mejorar el rendimiento académico de los estudiantes convirtiéndolos en protagonistas de su aprendizaje.El objetivo del presente trabajo es diseñar un modelo de componentes de aprendizaje (...) adaptativo para facilitar el desarrollo de habilidades en el área de metodología de la programación. (shrink)

The removal of water from mines was one of the key issues that former miners had to deal with. Roman colonists brought new technology to the Iberian Peninsula that addressed this problem. However, they did not invent this technology because it had already been applied to the growth of other endeavours in the Hellenistic society throughout the Eastern Mediterranean. In the mine, the Archimedes screw, waterwheels, bucket pulleys, and Ctesibius pumps were the primary drainage systems. In this essay, the primary (...) characteristics, and modes of operation of machines are examined. Without leaving out the most significant finds made in the southwest of the Iberian Peninsula, one of the regions with the longest history of mining exploitation. To serve as a foundation for future research in this field, this work compares the primary mining mechanisms in ancient Huelva on a qualitative and quantitative level by the implementation of a TOPSIS methodology, a multi-criteria decision analysis method. (shrink)

Este trabajo tiene como objetivo comentar algunas prohibiciones del padre Miguel Ángel de Tamburini y del padre Francisco Retz explicando los conceptos fundamentales de dichas prohibiciones a través de un método analítico y relacionándolos posteriormente bajo un método sintético con los argumentos presentados. Esto último permitirá realizar una reconstrucción de las prohibiciones cuyo ensamble se consolidará en argumentos breves. Asimismo, evaluar cuáles pueden ser las causas o los fundamentos que subyacen en las prohibiciones mismas, es decir, evaluar las causas (...) de su veto. Finalmente, determinar las implicaciones filosóficas de las prohibiciones desde Descartes, Leibniz y Spinoza y sus correspondientes visiones de la Creación, la voluntad, el determinismo y el principio de individuación. (shrink)

La noche de piedra and Los días de Mercurio are, until today, the two novels published of the trilogy La Iniquidad by Alexis Ravelo. They present two different stories and settings in the line of hard boiled and noir and in the best tradition of the Spanish thriller from the 70s and 80s, whose social and philosophical dimensions are recovered through an interesting treatment of the space and the reconstruction of historical memory. Ravelo reformulates the genre with narrative techniques typical (...) of postmodernism. His writing is close to the neopolicial genre in our cultural sphere and moves away from the new crime novel that succeeds in the publishing market. (shrink)

Resumen Aunque Carlos Arturo Truque sigue siendo poco conocido, no podemos hablar de literatura afrocolombiana, ni colombiana, sin su aporte. Con una producción literaria dispersa en publicaciones periódicas, el chocoano apuesta por el cuento cuando este no era suficientemente valorado en su país. Vivan los compañeros recoge todos sus cuentos, en los que se acerca tanto a los personajes excluidos de la sociedad como a los episodios de la historia colombiana más “vergonzosos”, desde un lenguaje que se aleja de todo (...) academicismo. Su obra, calificada en la época de “literatura sucia”, y ubicada concretamente en el Chocó y el puerto de Buenaventura, no es ajena a cualquier injusticia humana. Además, la necesidad de Truque de plasmar el habla de su comunidad no le impide contemplar las nuevas técnicas narrativas que llegaban entonces de Norteamérica. Así, renueva el cuento colombiano desde el plano formal y de contenido.Although Carlos Arturo Truque is still not well known, we cannot talk about Afro-Colombian, or Colombian literature, without mentioning his contribution. With an unfocused literary production in periodic publications, the “chocoano” bets on the short story when this genre was not highly valued in his country. Vivan los compañeros collects all his short stories, where he approaches the excluded characters of society as well as the more “shameful” episodes of Colombian history, from a language that distances itself from all academic art. His work, described at the time as “dirty literature” and specifically located in Chocó and the port of Buenaventura, is not alien to any human injustice. Besides, the need for Truque to express the speech of his community does not prevent him from contemplating new narrative techniques coming from North America. Thus, he renews the Colombian short story from the formal level and its content. (shrink)

Se busca rastrear la imagen que Platón tiene de Heráclito y articularla con la estructura argumentativa del Cratilo, para comprender las necesidades textuales a las que responde la doctrina del flujo perpetuo, es decir, la discusión sobre la corrección (ὀρθότης) del nombre. Gracias a la inclusión del testimonio heraclíteo, resulta posible rastrear la presunta consolidación de la tesis sobre los nombres primarios y los secundarios como el eje de la separación entre dos planos de realidad (uno estable y uno móvil) (...) y de la teoría de las Ideas -es decir, como la base de la epistemología platónica presente en los diálogos de madurez-. The article seeks to trace the image Plato has of Heraclitus and connect it with the argumentative structure of the Cratylus in order to understand the textual needs that give rise to the doctrine of perpetual flux, that is, the discussion regarding the correctness (ὀρθότης) of names. The inclusion of Heraclitus's testimony makes it possible to trace the alleged consolidation of the thesis regarding primary and secondary names as the axis of separation between two levels of reality (one stable, the other, changing) and the theory of Ideas -that is, as the basis of Plato's epistemology as set forth in the late dialogues-. (shrink)

En 1968 leíamos a Sartre y a Camus y, entre nosotros, Unamuno y Ortega se mezclaban con la poesía de Miguel Hernández o Blas de Otero, y las películas de Bergman. Vivir en la periferia, entonces, tenía limitaciones que el tiempo no subsana. Internet es hoy una posibilidad, cierto, pero también encubre, mistifica, mantiene a la conciencias individuales en su atomicidad sedente. Es su función ideológica y política, mientras se incrementan aquellas limitaciones. Aquella periferia tenía, al menos, la (...) excusa de la ‘dictadura’. Eran tiempos de lecturas frenéticas y de emociones intensas pero «vacías», sin horizontes ni concepto. Había otras ciudades, otros jóvenes, incluso entre nosotros. Había ya quienes se agrupaban, quienes leían a Marx, quienes viajaban y, sobre todo, quienes sufrían. (shrink)

Journal Name: Cognitive Linguistics Issue: Ahead of print.

This paper investigates the use of hashtags in the building of brand narratives (i.e. the open-ended, unfolding and participative depiction of a company’s core ideology and beliefs). A collection of over 700 hashtags involved in the creation of the advertising narratives of the four leading soft drinks brands in 2017 (i.e.Coca-Cola, Pepsi, RedBull, Nescafé) has been analyzed both quantitatively and qualitatively to unveil their functions and formal characteristics, as well as the cognitive processes that underlie their interpretation and operate on (...) the framing and dissemination of brand narratives. Ultimately, by categorizing and explaining the roles of hashtags in the construction of a brand narrative, as well as the potential correlations between their formal and functional traits and their retweeting rate and digital lifespan, this paper shapes a preliminary description of the characteristics of the subgenre of hashtag-based brand narratives and spells out some of the factors that should be considered in the choice of hashtags for advertising purposes. (shrink)

In the management and organization studies literature, a key question to explore and explain is that of the family as an organizational stakeholder, particularly when working-from-home became the “new normal”. Departing from meta-analytic studies on the work-family relation and connecting with scholarly conversation on work-family boundary dynamics, we identify three main narratives. In the _separation narrative,_ work and family belong to different realms, and including the family in the domain of organizational responsibility is seen as pointless. The _interdependence narrative_ stresses (...) that organizations and families are overlapping domains in which it is important to acknowledge that the policies and practices of the former might have an impact on family life, and vice-versa. The _embeddedness narrative_, brought to the fore by the COVID-19 pandemic, sees employment and family as progressively convergent and hybrid work domains. The evolution of employment relations towards increased hybridity of the work situation being embedded in the familial/household context increasingly calls for consideration of the family/household as an integral rather than a peripheral stakeholder. (shrink)

El libro de María González Navarro se presenta a sí mismo como una “nueva hermenéutica” (23). La novedad involucra dos aspectos: uno que llamaremos metateórico y otro hermenéutico en propiedad. Hablando metateóricamente, el libro presenta una hermenéutica gadameriana vigorizada y robustecida por las teorías pragma-dialécticas de la argumentación. Desde el punto de vista hermenéutico propiamente dicho, la novedad reposa en que se considera que la interpretación correcta está indesligablemente vinculada a la argumentación abductiva.

Genetic relatedness figures heavily in contemporary ethical debates on egg freezing, although the arguments lack empirical‐based evidence. Rather than adding another theoretical view on the moral relevance of genetic connections, this paper instead proposes an empirically grounded perspective based on two independent qualitative interview‐based studies conducted in Belgium and France. Three themes emerge from our empirical data: (1) prioritizing family building; (2) centering the gestational experience of motherhood; and (3) identifying the complexities and limitations of adoption. These themes suggest that (...) the relationship between egg freezing, genetics, biological motherhood, and adoption is highly complex and less straightforward than what is often assumed in the egg freezing debate. Our study provides more detailed insights into women's ambivalent experiences regarding those reproductive options. We discuss the ethical implications of our empirical findings and hold that pursuing genetic desire is not necessarily the main moral reason why women freeze their eggs. (shrink)

La acción de los medios de prensa de construir y representar realidades socioculturales genera --en reiteradas ocasiones-- relaciones desiguales, promoviendo e institucionalizando unas identidades en desmedro de otras. La situación se complejiza cuando se trata de países vecinos, con sus respectivas tradiciones socio-histórico-culturales, pasados comunes y límites bisagra. Bajo este escenario se analizaron las producciones noticiosas de cobertura nacional publicadas en los periódicos de mayor tirada de dos países limítrofes: “El Mercurio” de Chile y “El Comercio” de Perú. De este (...) modo, y por medio de una herramienta metodológica ligada al Análisis Crítico y Complejo del Discurso, esta investigación busca comprender los procesos de construcciones noticiosas y representaciones que los medios de prensa chilenos y peruanos hacen en torno a los “discursos de la diferencia” que se institucionalizan en la relación entre ambas naciones. The action of the press media of constructing and representing socio-cultural realities generates --on numerous occasions-- unequal relationships, which promote and institutionalize certain identities in detriment of others. The situation becomes more complex when it deals with neighboring countries and their corresponding socio-historical-cultural traditions, shared pasts, and “hinge-like” borders. Under this scenario, the production of national news by two nationwide press media of the neighboring countries will be analyzed: “El Mercurio” of Chile and “El Comercio” of Perú. In this manner, and using a methodological tool based on the Critical and Complex Analysis of the Discourse, the main objective of this research is to understand processes of construction of news and representations that the Chilean and Peruvian press make linked to the “discourse of the differences” which have been institutionalized in the relationship between them both. (shrink)

Desde la tradición humanista occidental se ha instituido una oposición radical entre el ser humano y el animal no-humano en tanto dos regímenes de existencia diferentes e irreconciliables; oposición que ha partido, esencialmente, de una construcción ficcional del hombre y de lo “propiamente humano” como especie superior y dominante respecto al resto de los vivientes. Dicho fenómeno, o fabulación, ha venido aparejado, además, de un proceso de no reconocimiento de la animalidad que habita en el hombre y de la urgencia (...) por suprimir tales rasgos como si se tratase de una dimensión inaceptable de la existencia humana. El artículo examina, entonces, algunos de aquellos rasgos del paradigma humanista occidental que han delineado relaciones binarias y especistas en el mundo contemporáneo y que han negado lo animal en la búsqueda de lo “propiamente humano”. El trabajo hace un breve recorrido por algunas de las hipótesis que han abordado, desde diversos posicionamientos, la problemática de los animales: Berger, Descartes, Sloterdijk, Agamben, Derrida y Bailly son algunos de los aludidos. En ese sentido, el ensayo explora determinados tópicos teóricos, entre los que se encuentran: el animal-máquina cartesiano, las civilizaciones como invernaderos antropogénicos, la máquina antropocéntrica y la riqueza de mundo de lo animal. (shrink)

El artículo tiene por objeto analizar la construcción del conocimiento mapuche según el discurso de kimches. Sostenemos que en la educación familiar existe un proceso de construcción de conocimientos propios como un sistema de saberes y contenidos educativos para la formación de personas. La metodología empleada es la investigación educativa. Los resultados parciales muestran una descripción acerca de la lógica de los conocimientos educativos propios, para contextualizar la enseñanza y el aprendizaje de las ciencias en el medio escolar, desde la (...) educación intercultural en contexto mapuche. The aim of this article is to analyze the construction of Mapuche knowledge based on the kimches speech. We argue that within family education, there exists a process of constructing their own knowledge, as a system of knowledge and educational contents for forming individuals. The research methodology applied corresponds to education research. Preliminary results describe the logic of individual educational knowledge from intercultural education in the Mapuche context, so as to contextualize the teaching and learning of Science in schools. (shrink)

Este trabajo examina parte del pensamiento de Kant de cara a precisar en qué sentido puede pensarse la universalidad como una exigencia para la filosofía moral y cómo las investigaciones de ese autor pueden contribuir a esclarecer esta cuestión. El análisis de los argumentos muestra algunas inconsistencias lógicas en el desarrollo del problema de la universalización moral que los especialistas han tratado de explicar, a partir de las cuales sugerimos que una alternativa de análisis gramatical al estilo de Wittgenstein puede (...) ayudar a clarificar. El trabajo es, pues, crítico y pro positivo y conlleva una interpretación programática de tesis kantianas. (shrink)

Unamuno’nun Sis adlı romanı gerçekliğin doğasına ilişkin felsefi bir sorgulama edimini bir aşk hikâyesi etrafında sembolize ederek dolaylı bir biçimde okuyucuya sunmaktadır. Eserin kahramanı Augusto Pérez’in varoluşsal krizinin kurgu ve gerçeklik arasındaki ilişkiyle birlikte farklı bir boyuta taşındığı bu roman, hayatın anlamı, ölümsüzlük arzusu ve bireyin tanrıyla olan ilişkisi gibi temaları varoluş ve kimlik arayışı ekseni etrafında şekillendirerek tartışmaya açmaktadır. Nesnel gerçeklik ve öznel hakikat arasında gidip gelen bu tartışma, Unamuno’nun varoluşçuluğu hakkında önemli ipuçları taşımakta ve kavramsal kişilikler aracılığıyla (...) ustaca ortaya koyduğu diyalog yöntemini dâhiyane edebi üslubuyla birleştirmektedir. Hayatın muğlaklıklarla dolu belirsiz bir yapısı olduğunu ifade eden Unamuno için yaşamın kendisi bir sistir. Dahası, yaşamın tüm canlılığının ve dinamikliğinin taşıyıcısı olan bu sisi aklın ve mantığın ışığında dağıtmaya ve berraklaştırmaya çalışmanın kendisinin komik olduğunu belirten Unamuno, yaşamın anlamının tam da bu trajik anlamı içinde ortaya çıktığını iddia eder. Aklın bildikleri ile kalbin inandıkları arasında insan absürt ve paradoksal olana adeta Kierkegaardcı bir iman sıçramasıyla bağlanmalıdır. Unamuno’nun varoluşçuluğunu gerçeklik problemi bağlamında değerlendirmeye çalışan bu makalenin amacı, varoluşun kurgu ve gerçeklik arasındaki özel yerini öznel bir iç hesaplaşmaya dönüştürme gerekliliğine dikkat çekmektir. (shrink)

We compare the traits of companies receiving social policy shareholder resolutions with those of a set of matching firms. We show that targeted firms tend to be much larger and riskier, less profitable and less socially performing than their counterparts. The five largest investors in firms receiving social proxies tend to hold a lower stake in those firms vis‐à‐vis the matching firms. Firms in both samples, however, are not statistically different in terms of percentages of shares held by institutional and (...) insider investors. We provide possible explanations for our results. (shrink)

Most studies investigating the relationship between cultural constructs and ethical perception have focused on individual- and societal-level values without much attention to other type of cultural constructs such as social beliefs. In addition, we need to better understand how social beliefs are linked to ethical perception and the level of analysis at which social beliefs may best predict ethical perceptions. This research contributes to the cross-cultural ethical perception literature by examining the relationship of individual-level social cynicism belief, one of five (...) universally endorsed social beliefs, together with individual social dominance orientation and the perception of unethical behavior. By means of two studies, we examine these relationships across societies that significantly differ on societal-level social cynicism belief. Using 371 business students from Russia and the U.S. in Study 1 and 268 professionals from Portugal and the U.S. in Study 2, we found that individual-level social cynicism belief was positively associated with social dominance orientation. Social dominance orientation, in turn, mediated the relationship between individual social cynicism belief and the perception of unethical behavior. Although we found significant societal-level differences in social cynicism belief in both studies, the relationships between individual-level social cynicism belief, social dominance orientation, and the perception of unethical behavior were structurally equivalent across societies in both studies, suggesting that societal-level differences did not significantly affect these relationships. Implications for cross-cultural business ethics research and practice are discussed. (shrink)

Because a large number of molecular mechanisms involved in gene regulation have been described during the last decades, it is now becoming possible to address questions about the global structure of gene regulatory networks, at least in the case of some of the best-characterized organisms.This paper presents a global characterization of the transcriptional regulation in Escherichiacoli on the basis of the current data. The connectivity of the corresponding network was evaluated by analyzing the distribution of the number of genes regulated (...) by a given regulatory protein, and the distribution of the number of regulatory genes regulating a given regulated gene. The mean connectivity found (between 2 and 3) shows a rather loosely interconnected structure. Special emphasis is given to circular sequences of interactions (“circuits”) because of their critical dynamical properties. Only one-element circuits were found, in which negative autoregulation is the dominant architecture. These global properties are discussed in light of several pertinent theoretical approaches, as well as in terms of physiological and evolutionary considerations. BioEssays 20:433–440, 1998. © 1998 John Wiley & Sons Inc. (shrink)

Because a large number of molecular mechanisms involved in gene regulation have been described during the last decades, it is now becoming possible to address questions about the global structure of gene regulatory networks, at least in the case of some of the best-characterized organisms.This paper presents a global characterization of the transcriptional regulation in Escherichiacoli on the basis of the current data. The connectivity of the corresponding network was evaluated by analyzing the distribution of the number of genes regulated (...) by a given regulatory protein, and the distribution of the number of regulatory genes regulating a given regulated gene. The mean connectivity found (between 2 and 3) shows a rather loosely interconnected structure. Special emphasis is given to circular sequences of interactions (“circuits”) because of their critical dynamical properties. Only one-element circuits were found, in which negative autoregulation is the dominant architecture. These global properties are discussed in light of several pertinent theoretical approaches, as well as in terms of physiological and evolutionary considerations. BioEssays 20:433–440, 1998. © 1998 John Wiley & Sons Inc. (shrink)