Sexual eukaryotic organisms are characterized by an alternation between haploid and diploid phases. In vascular plants and animals, somatic growth and development occur primarily in the diploid phase, with the haploid phase reduced to the gametic cells. In many other eukaryotes, however, growth and development occur in both phases, with substantial variability among organisms in the length of each phase of the life cycle. A number of theoretical models and experimental studies have shed light on factors that may influence life (...) cycle evolution, yet we remain far from a complete understanding of the diversity of life cycles observed in nature. In this paper we review the current state of knowledge in this field, and touch upon the many questions that remain unanswered. BioEssays 20:453–462, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

An “insightful” and in-depth look at anti-science politics and its deadly results (Maria Konnikova, New York Times–bestselling author of The Biggest Bluff). Thomas Jefferson said, “Wherever the people are well informed, they can be trusted with their own government.” But what happens when they aren’t? From climate change to vaccinations, transportation to technology, health care to defense, we are in the midst of an unprecedented expansion of scientific progress—and a simultaneous expansion of danger. At the very time we need them (...) most, scientists and the very idea of objective knowledge are being bombarded by a vast, well-funded war on science, and the results are deadly. Whether it’s driven by identity politics, ideology, or industry, the result is an unprecedented erosion of thought in Western democracies as voters, policymakers, and justices actively ignore scientific evidence, leaving major policy decisions to be based more on the demands of the most strident voices. This compelling book investigates the historical, social, philosophical, political, and emotional reasons why evidence-based politics are in decline and authoritarian politics are once again on the rise on both left and right—and provides some compelling solutions to bring us to our collective senses, before it's too late. “If you care about attacks on climate science and the rise of authoritarianism, if you care about biased media coverage and shake-your-head political tomfoolery, this book is for you.”—The Guardian. (shrink)

Este trabajo trata de mostrar cómo sobre la base de una filosofía del ingenio, Vico se dispone a delinear una representación figurada fundamentándose sobre una "convertibilidad" de los signos y de sus significados así como de los "conjuntos" de signos y su representación figurativa. La denominada "semiótica" viquiana se transforma a sí misma en una "sematología" de la "representación histórica".This paper intends to show how Vico sets himself to shape a figurative representation on the basis of the philosophy of wit. (...) In doing so, he takes as foundation the "convertibility" of signs and their meanings together with the "sets" of signs and their figurative representation. The so called Vichian "semiotics" is thus shifted into a "sematology" of the historical representation. (shrink)

Few topics have intrigued biologists as much as the evolution of sex. Understanding why sex persists despite its costs requires not just rigorous theoretical study, but also empirical data on related fundamental issues, including the nature of genetic variance for fitness, patterns of genetic interactions, and the dynamics of adaptation. The increasing feasibility of examining genomes in an experimental context is now shedding new light on these problems. Using this approach, McDonald et al. recently demonstrated that sex uncouples beneficial and (...) deleterious mutations, allowing selection to proceed more effectively with sex than without. Here we discuss the insights provided by this study, along with other recent empirical work, in the context of the major theoretical models for the evolution of sex. (shrink)

In this article we offer analysis of the intersection between what is theorized as the knowledge economy, US schools, and identity politics through our examination of a sample of print media advertisements. The thematic thread we use to tie these pieces together is the concept of smartness, which we frame as a metanarrative of truth reflected in schooling and society. In sum, 156 advertisements are examined and discourses of smartness, race/ethnicity, and gender analyzed. We discuss the ways power has shifted (...) within the knowledge economy to privilege smart identities as representations of human capital and those representations? connections to schooling. (shrink)

Hay toda una serie de preguntas que giran en torno a la problemática interna misma de la Scienza Nuova, y que sólo un "nuevo" concepto de ciencia -vinculado a la crítica de Vico a la formación de sistemas característica de la temprana Modernidad- las consigue responder de manera efectiva, bosquejando una nueva idea "orgánica" entre saber especulativo-teórico y saber orientado a los estados de cosas.There is a whole series of questions that revolves around the core problem of the Scienza Nuova: (...) only a "new" concept of science -linked to Vico's criticism of the formation of systems, characteristic of the early modernity- is able to respond to these questions in an effective manner, sketching a new "organic" idea between speculative-theoretical knowledge and knowledge directed to the state of things. (shrink)

El escrito de la Ciencia Nueva es un texto cifrado. Pero quizá pueda descifrarse –él y la entera obra viquiana– mediante el juego conjugado de dos claves hermeneúticas inseparables: la una metafísica, semiótica la otra. Ambas se condicionan recíprocamente por la idea de “sintesis geométrica” cuya textualización descansa a su vez en un subtexto no escrito. Este subtexto posibilitador de la síntesis de semiótica en Vico no es otro que su modo de pensamiento transcendental, en nada kantiano, moderno en todo.The (...) writing of Scienza Nuova is an encoded text. It might perhaps be deciphered not only that very text but the whole Vico’s work as well by using the connected game of two distintics hermeneutic cleves: one is metaphysical, the other semiotic. Both maintein a mutual relationship and both also are conditioned by the "geometrical syntax", a textualiztion of which seems torest in a non-written text. This subtext which makes possible to carry a complete synthesis of both metaphysics and semiotic in Vico, is nothing but his particular way of transcendental thinking, which has little to do with the Kantian tradition and is fully rooted in the contemporay thinking. (shrink)

Genetic variation in fitness is the fundamental prerequisite for adaptive evolutionary change. If there is no variation in survival and reproduction or if this variation has no genetic basis, then the composition of a population will not evolve over time. Consequently, the factors influencing genetic variation in fitness have received close attention from evolutionary biologists. One key factor is the mode of reproduction. Indeed, it has long been thought that sex enhances fitness variation and that this explains the ubiquity of (...) sexual reproduction among eukaryotes. Nevertheless, theoretical studies have demonstrated that sex need not always increase genetic variation in fitness. In particular, if fitness interactions among beneficial alleles (epistasis) are positive, sex can reduce genetic variance in fitness. Empirical data have been sorely needed to settle the issue of whether sex does enhance fitness variation. A recent flurry of studies1-4 has demonstrated that sex and recombination do dramatically increase genetic variation in fitness and consequently the rate of adaptive evolution. Interpreted in light of evolutionary theory, these studies rule out positive in these experiments epistasis as a major source of genetic associations. Further studies are needed, however, to tease apart other possible sources. BioEssays 25:533–537, 2003. © 2003 Wiley Periodicals, Inc. (shrink)