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Distribution by Scientific Domains

Humanities and Social Sciences	40%

Selected Abstracts

Shell structure, ontogeny and affinities of the Lower Cambrian bivalved problematic fossil Mickwitzia muralensis Walcott, 1913

LETHAIA, Issue 4 2004
UWE BALTHASAR
Exceptionally preserved carbonate- and shale-hosted Mickwitzia muralensis from the Lower Cambrian Mural Formation, southern Canadian Rocky Mountains, complement one another to yield an unusually complete account of its ontogeny, ecology and phylogenetic relationships. The shell of M. muralensis is composed of dense phosphatic layers interspersed with porous organic-rich layers. At the insertion of shell-penetrating tubes, shell layers deflect inwards to produce inwardly pointing cones. The tubes are interpreted as having hosted setae that were secreted by outer-epithelial follicles. Follicular setae also occurred at the mantle margin, where they were oriented within the plane of the shell as in modern brachiopods. During ontogeny, the initial setae oriented in the plane of the shell occurred before the first shell-penetrative setae. In the juvenile and early-mature stages of shell secretion, a posterior opening was present between both valves and was used for the protrusion of an attachment structure. In the late-mature shell, this opening became fixed in the ventral valve. Based on the posterior margin and the shell microstructure, a close relationship between Mickwitzia and the paterinids is proposed with differences interpreted as heterochronic. The shell-penetrative setal apparatus of M. muralensis is distinct from that previously described of Micrina, though both types are conceivably homologous to adult and juvenile setae of modern brachiopods. [source]

Epistemic Presuppositions and their Consequences

METAPHILOSOPHY, Issue 1-2 2003
Juli Eflin
Traditional epistemology has, in the main, presupposed that the primary task is to give a complete account of the concept knowledge and to state under what conditions it is possible to have it. In so doing, most accounts have been hierarchical, and all assume an idealized knower. The assumption of an idealized knower is essential for the traditional goal of generating an unassailable account of knowledge acquisition. Yet we, as individuals, fail to reach the ideal. Perhaps more important, we have epistemic goals not addressed in the traditional approach , among them, the ability to reach understanding in areas we deem important for our lives. Understanding is an epistemic concept. But how we obtain it has not traditionally been a focus. Developing an epistemic account that starts from a set of assumptions that differ from the traditional starting points will allow a different sort of epistemic theory, one on which generating understanding is a central goal and the idealized knower is replaced with an inquirer who is not merely fallible but working from a particular context with particular goals. Insight into how an epistemic account can include the particular concerns of an embedded inquirer can be found by examining the parallels between ethics and epistemology and, in particular, by examining the structure and starting points of virtue accounts. Here I develop several interrelated issues that contrast the goals and evaluative concepts that form the structure of both standard, traditional epistemological and ethical theories and virtue,centered theories. In the end, I sketch a virtue,centered epistemology that accords with who we are and how we gain understanding. [source]

Nearby stars of the Galactic disk and halo.

ASTRONOMISCHE NACHRICHTEN, Issue 1 2004

Abstract High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk , our "familiar Milky Way" , came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy , and by inference many other spirals as well , if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at , , 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary , Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the UrsaMajor Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though systematic effect on the basic solar motion, (iii) a reassessment of the term "asymmetrical drift velocity" for the remainder (i.e. the thin disk) of the stellar objects, (iv) its ability to account for the bulk of the recently discovered high-velocity blue white dwarfs, (v) its major contribution to the Sun's ,220 km s,1 rotational velocity around the Galactic center, and (vi) the significant flattening that it imposes on the Milky Way's rotation curve. Finally we note a high multiplicity fraction in the small but volume-complete local sample of stars of this ancient population. This in turn is highly suggestive for a star formation scenario wherein the few existing single stellar objects might only arise from either late mergers or the dynamical ejection of former triple or higher level star systems. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

An extended performance reporting framework for social and environmental accounting

BUSINESS STRATEGY AND THE ENVIRONMENT, Issue 5 2006
Kittiya Yongvanich
Abstract Internationally, there is growing awareness of the environmental and social impacts of the business activities of organizations. This awareness was heightened by the 1987 report Our Common Future by the World Commission on Environment and Development (WCED, 1987). In order to address the concerns raised, companies have increasingly reported the social and environmental impacts of their business activities to secure their right to operate from society. This paper argues for the importance of an integrated reporting framework that provides information on economic performance via intellectual capital (IC) information and non-economic performance, including that used in the management of performance across social and environmental impacts. This paper briefly reviews three extended reporting approaches, namely IC, balanced scorecard (BSC) and social and environmental reporting. The paper demonstrates that the emphases of these reporting approaches, while diverse, could be complementary to one another and be integrated into an extended performance reporting framework (EPRF), which would provide a more complete account of the management and performance of an organization. The EPRF could empower stakeholders and facilitate change in the way organizations conduct their activities. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source]

Extending phylogenetic studies of coevolution: secondary Brooks parsimony analysis, parasites, and the Great Apes

CLADISTICS, Issue 2 2003
Daniel R Brooks
Dowling recently compared the empirical properties of Brooks parsimony analysis (BPA) and the leading method for studying phylogenetic aspects of coevolution, reconciled tree analysis (using the computer program TreeMap), based on a series of simulations. Like the majority of authors who have compared BPA with other methods, however, Dowling considered only the form of BPA proposed in 1981 and did not take into account various modifications of the method proposed from 1986 to 2002. This leaves some doubt as to the robustness of his assessments of both the superiority of BPA and its shortcomings. We provide a précis of the principles of contemporary BPA, including ways to implement it algorithmically, using either Wagner algorithm-based or Hennigian argumentation-based approaches, followed by an empirical example. Our study supports Dowling's fundamental conclusions about the superiority of primary BPA relative to TreeMap. However, his conclusions about the shortcomings of BPA due to inclusive ORing (i.e., the production of ghost taxa) are incorrect, as secondary BPA eliminates inclusive ORing from the method. Secondary BPA provides a more complete account of the evolutionary associations between the parasite groups and their hosts than does primary BPA, without sacrificing any indirectly generated information about host phylogeny. Secondary BPA of two groups of nematodes inhabiting Great Apes shows that TreeMap analysis underestimated the amount of cospeciation in the evolution of the nematode genus Enterobius. [source]