The origin of eukaryotes is one of the major challenges of evolutionary cell biology. Other than the endosymbiotic origin of mitochondria and chloroplasts, the steps leading to eukaryotic endomembranes and endoskeleton are poorly understood. Ras‐family small GTPases are key regulators of cytoskeleton dynamics, vesicular trafficking and nuclear function. They are specific for eukaryotes and their expansion probably traces the evolution of core eukaryote features. The phylogeny of small GTPases suggests that the first endomembranes to evolve during eukaryote evolution had secretory, (...) and not phagocytic, function. Based on the reconstruction of putative roles for ancestral small GTPases, a hypothetical scenario on the origins of the first endomembranes, the nucleus, and phagocytosis is presented. BioEssays 25:1129–1138, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Los recientes acontecimientos económicos y su trascendental repercusión a nivel mundial, tienen entre alguna de sus más notables consecuencias la caída generalizada en los niveles de consumo. Paralelamente otro de los fenómenos cuasi-globales, el consumo masivo de objetos, se caracteriza cada vez más por la frugalidad de dichos objetos de consumo y la necesidad de sustituirlos por otros que aporten alguna novedad; lo que implica que el consumidor no pueda descansar en sus ansias consumistas. A partir de la unión de (...) estos dos aspectos, crisis económica y consumo posmoderno, se plantea un análisis social de algunos de los aspectos que caracterizan a la sociedad de consumo española en el momento presente y su repercusión en la distribución del gasto. (shrink)

The cilium/flagellum is a sensory-motile organelle ancestrally present in eukaryotic cells. For assembly cilia universally rely on intraflagellar transport (IFT), a specialised bidirectional transport process mediated by the ancestral and conserved IFT complex. Based on the homology of IFT complex proteins to components of coat protein I (COPI) and clathrin-coated vesicles, we propose that the non- vesicular, membrane-bound IFT evolved as a specialised form of coated vesicle transport from a protocoatomer complex. IFT thus shares common ancestry with all protocoatomer derivatives, (...) including all vesicle coats and the nuclear pore complex (NPC). This has major implications for the evolutionary origin of the cilium. First, it reinforces the tenet that duplication and divergence of pre-existing structures, rather than symbiosis, were the major themes during cilium evolution. Second, it suggests that the initial step in the autogenous origin of the cilium was the establishment of a membrane patch with transmembrane proteins transported by the ancestral vesicle-coating IFT complex. We propose a scenario for how the initial membrane patch gradually protruded to enhance exposure to the environment, then started to move, and finally compartmentalised to render receptor signalling and ciliary beating more efficient. BioEssays 28: 191–198, 2006. © 2006 Wiley periodicals, Inc. (shrink)

La encarnación del Verbo de Dios, que culmina en el misterio pascual de la muerte y resurección de Jesucristo, es el hecho fundamental y la novedad radial del Cristianismo. En la encarnación del Verbo, el Dios infinito y creador se autocomunica amorosamente a lo otro creado, para redención y divinización del hombre, para recapitulación del cosmos.

We examined how the cultural dimension of universalism–particularism influences managers’ attitudes toward relational favoritism. Paradoxically, we found in a survey study that Brazilian and Chinese managers perceived more negative consequences of relational favoritism than did American managers—even though the Brazilians and the Chinese perceived stronger particularistic cultural norms in their countries than Americans did in the United States. We attribute this pattern of results to “cultural reflexivity”—the ability of people from transforming economies to be culturally self-critical during a period of (...) dramatic societal change. This pattern of results also emerged in a scenario study in which we asked these same Brazilian, Chinese, and American participants to assess managerial succession decisions made by a General Manager. We varied the scenarios so that the promoted manager was either a colleague with no pre-existing relation with the GM or a colleague who was a relative, a close friend, from the same town, or from the same school. Consistent with the results of the survey study, we found that perceived cultural norms of particularism were negatively related to perceptions of fairness. In other words, Brazilians and Chinese, even while living in more particularistic cultures, were more harsh in judging relational favoritism. We conclude with a discussion on the implications of these paradoxical relationships. (shrink)

ABSTRACT:U.S. Organizational Sentencing Guidelines provide firms with incentives to develop formal ethics programs to promote ethical organizational cultures and thereby decrease corporate offenses. Yet critics argue such programs are cosmetic. Here we studied bank employees before and after the introduction of formal ethics training—an important component of formal ethics programs—to examine the effects of training on ethical organizational culture. Two years after a single training session, we find sustained, positive effects on indicators of an ethical organizational culture (observed unethical behavior, (...) intentions to behave ethically, perceptions of organizational efficacy in managing ethics, and the firm’s normative structure). While espoused organizational values also rose in importance post-training, the boost dissipated after the second year which suggests perceptions of values are not driving sustained behavioral improvements. This finding conflicts with past theory which asserts that enduring behavioral improvements arise from the inculcation of organizational values. Implications for future research are discussed. (shrink)

Con un'impostazione che coniuga la fedeltà testuale e l'approfondimento critico, il percorso di questo libro mira a ricondurre l'edificazione kierkegaardina - spesso considerata mera esortazione spirituale - allo spessore autenticamente filosofico d'una via soggettiva alla verità. Un modello antioggettivistico di filosofare senza perdere di vista né l'esercizio del dubbio né la dimensione della fede. Attraverso l' interpretazione kierkegaardiane di C. Fabro si è giunti all'esposizione e ai lineamenti descrittivi fondamentali della nozione del singolo. Il singolo viene presentato dallo stesso Kierkegaard (...) come la mia categoria. Sta di fatto che si può intendere l'intera produzione kierkegaardiana come un pensare soggettivamente il singolo. Pensiero etico carico di conseguenze pratiche, giacchè il danese non pretendeva fondare una scuola filosofica ma soltanto rendere attenti, svegliare le coscienze. (shrink)

ABSTRACT:U.S. Organizational Sentencing Guidelines provide firms with incentives to develop formal ethics programs to promote ethical organizational cultures and thereby decrease corporate offenses. Yet critics argue such programs are cosmetic. Here we studied bank employees before and after the introduction of formal ethics training—an important component of formal ethics programs—to examine the effects of training on ethical organizational culture. Two years after a single training session, we find sustained, positive effects on indicators of an ethical organizational culture (observed unethical behavior, (...) intentions to behave ethically, perceptions of organizational efficacy in managing ethics, and the firm’s normative structure). While espoused organizational values also rose in importance post-training, the boost dissipated after the second year which suggests perceptions of values are not driving sustained behavioral improvements. This finding conflicts with past theory which asserts that enduring behavioral improvements arise from the inculcation of organizational values. Implications for future research are discussed. (shrink)

This paper extends earlier work by its authors on formal aspects of the processes of contracting a theory to eliminate a proposition and revising a theory to introduce a proposition. In the course of the earlier work, Gardenfors developed general postulates of a more or less equational nature for such processes, whilst Alchourron and Makinson studied the particular case of contraction functions that are maximal, in the sense of yielding a maximal subset of the theory (or alternatively, of one of (...) its axiomatic bases), that fails to imply the proposition being eliminated. In the present paper, the authors study a broader class, including contraction functions that may be less than maximal. Specifically, they investigate "partial meet contraction functions", which are defined to yield the intersection of some nonempty family of maximal subsets of the theory that fail to imply the proposition being eliminated. Basic properties of these functions are established: it is shown in particular that they satisfy the Gardenfors postulates, and moreover that they are sufficiently general to provide a representation theorem for those postulates. Some special classes of partial meet contraction functions, notably those that are "relational" and "transitively relational", are studied in detail, and their connections with certain "supplementary postulates" of Gardenfors investigated, with a further representation theorem established. (shrink)

El artículo se enfoca en el dilema al que se enfrentan los gobiernos democráticos para hacer frente a la amenaza del terrorismo. Desde el marco de la filosofía política, el autor busca aportar un enfoque que contribuya a la discusión del tema. Como contexto, toma en cuenta las medidas implementadas después del 11 de septiembre de 2001, por parte de los gobiernos de Estados Unidos de América y de países de Europa para combatir al terrorismo. La mayoría de los gobiernos (...) coincide en que, para garantizar la seguridad de sus ciudadanos frente al peligro del terrorismo, es necesario un recorte de libertades en favor de buscar el fortalecimiento del gobierno. (shrink)

In this article, Carlos Pereda introduces the concept of “colonial reason” and explores how philosophical practices and modes of thought are entwined with colonial political structures of exploitation, exclusion, and oppression. Pereda argues that philosophy in Latin America risks perpetuating and reinforcing the colonial gesture, either by turning to the European centers of thought (thus pursuing debates that always take place elsewhere) or by isolating itself and idealising the “own.” According to Pereda, both approaches fail to dismantle colonial violence (...) within philosophy. In his alternative approach, Pereda outlines principles and methodological criteria for the decolonisation of reason and philosophy. He emphasises the importance of methodological prudence that discerns between innocent, paralysing, and strategic uses of identity expressions and advocates for modes of reading and argumentation that conceive philosophy as an inclusive and ongoing dialogue. In Pereda’s terminology, this entails fostering “permeable reason” that manifests itself through “nomadic thinking,” a form of thinking that is capable of questioning itself and being questioned. (shrink)

Many of the computing systems programmed using Machine Learning are opaque: it is difficult to know why they do what they do or how they work. Explainable Artificial Intelligence aims to develop analytic techniques that render opaque computing systems transparent, but lacks a normative framework with which to evaluate these techniques’ explanatory successes. The aim of the present discussion is to develop such a framework, paying particular attention to different stakeholders’ distinct explanatory requirements. Building on an analysis of “opacity” from (...) philosophy of science, this framework is modeled after accounts of explanation in cognitive science. The framework distinguishes between the explanation-seeking questions that are likely to be asked by different stakeholders, and specifies the general ways in which these questions should be answered so as to allow these stakeholders to perform their roles in the Machine Learning ecosystem. By applying the normative framework to recently developed techniques such as input heatmapping, feature-detector visualization, and diagnostic classification, it is possible to determine whether and to what extent techniques from Explainable Artificial Intelligence can be used to render opaque computing systems transparent and, thus, whether they can be used to solve the Black Box Problem. (shrink)

The received view of dynamical explanation is that dynamical cognitive science seeks to provide covering law explanations of cognitive phenomena. By analyzing three prominent examples of dynamicist research, I show that the received view is misleading: some dynamical explanations are mechanistic explanations, and in this way resemble computational and connectionist explanations. Interestingly, these dynamical explanations invoke the mathematical framework of dynamical systems theory to describe mechanisms far more complex and distributed than the ones typically considered by philosophers. Therefore, contemporary dynamicist (...) research reveals the need for a more sophisticated account of mechanistic explanation. (shrink)

Models developed using machine learning are increasingly prevalent in scientific research. At the same time, these models are notoriously opaque. Explainable AI aims to mitigate the impact of opacity by rendering opaque models transparent. More than being just the solution to a problem, however, Explainable AI can also play an invaluable role in scientific exploration. This paper describes how post-hoc analytic techniques from Explainable AI can be used to refine target phenomena in medical science, to identify starting points for future (...) investigations of causal relationships, and to generate possible explanations of target phenomena in cognitive science. In this way, this paper describes how Explainable AI—over and above machine learning itself—contributes to the efficiency and scope of data-driven scientific research. (shrink)

In a context of pervasive digitalization of the social world, both before and during the COVID-19 pandemic, the field of education has undergone major changes with the development of digital practices and settings. However, the physical presence of the subjects and the body remain something primordial and irreplaceable in traditional educational processes. Thus, it is often assumed that virtuality is opposed to the corporeal reality of the subjects involved in teaching, learning and studying. In this paper we aim to critically (...) challenge this assumption by addressing the phenomenon of virtuality in a more original sense: as a fundamental dimension of corporeality itself. Drawing on Merleau-Ponty’s phenomenological insights, we argue that the experience of the virtual is inherently embodied and fully real. We understand corporeality and virtuality as entangled and multidimensional phenomena. At the same time, this leads us to rethink the digital as only one possible medium in which virtuality can appear as inherent to embodied experience. We develop our phenomenological approach in three instances. First, we question and bracket two common assumptions about corporeality. From our critical perspective, assumptions about a disembodied digitality and a devirtualized corporeality represent extremes within which educational discourses currently move. Second, we address the inherent virtuality of embodied experience. We outline the heuristic concept of the virtual body to describe corporeality and virtuality as entangled and multidimensional phenomena that encompass extension, intercorporeality and intermediality. Finally, we make some remarks on the relationships of corporeality and virtuality considering the challenges of digital education. (shrink)