46 research outputs found

    The Impact of New Technologies on the Environment

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    One of the objectives of IIASA's Study "Future Environments for Europe: Some Implications of Alternative Development Paths" is to characterize the large-scale and long-term environmental transformations that could be associated with plausible scenarios of Europe's socio-economic development over the next century. The purpose of this task is to help foresee potentially serious environmental problems before they actually occur. This Working Paper is an important contribution toward that goal. It is becoming increasingly clear that the linkages between technologies and their long-term effects on the environment require more careful attention and forethought than has been the case in the past. The socio-economic benefits of technologies are usually proportional to their scale of application, and the rewards are reaped almost instantaneously. The problem, however, is that the "disbenefits", in terms of ecological degradation, often very nonlinearly with the scale of application, and are manifested on relatively slow time scales. The danger of this syndrome is that the technology may tend to become entrenched over time, making it difficult for adjustment or change by the time the disbenefits become manifest. Therefore, this timely paper should be of interest to all those who ponder the long-term trade-offs between technological development and environmental degradation

    Kin and Clan

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    Temporal inflection points in decorated pottery: a bayesian refinement of the late formative chronology in the Southern Lake Titicaca Basin, Bolivia

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    The Late Formative period immediately precedes the emergence of Tiwanaku, one of the earliest South American states, yet it is one of the most poorly understood periods in the southern Lake Titicaca Basin (Bolivia). In this article, we refine the ceramic chronology of this period with large sets of dates from eight sites, focusing on temporal inflection points in decorated ceramic styles. These points, estimated here by Bayesian models, index specific moments of change: (1) cal AD 120 (60-170, 95% probability): the first deposition of Kalasasaya red-rimmed and zonally incised styles; (2) cal AD 240 (190-340, 95% probability): a tentative estimate of the final deposition of Kalasasaya zonally incised vessels; (3) cal AD 420 (380-470, 95% probability): the final deposition of Kalasasaya red-rimmed vessels; and (4) cal AD 590 (500-660, 95% probability): the first deposition of Tiwanaku Redwares. These four modeled boundaries anchor an updated Late Formative chronology, which includes the Initial Late Formative phase, a newly identified decorative hiatus between the Middle and Late Formative periods. The models place Qeya and transitional vessels between inflection points 3 and 4 based on regionally consistent stratigraphic sequences. This more precise chronology will enable researchers to explore the trajectories of other contemporary shifts during this crucial period in Lake Titicaca Basin's prehistory.Fil: Marsh, Erik Johnson. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de PaleoecologĂ­a Humana; ArgentinaFil: Roddick, Andrew P.. Mc Master University; CanadĂĄFil: Bruno, Maria C.. Dickinson College; Estados UnidosFil: Smith, Scott C.. Franklin & Marshall College; Estados UnidosFil: Janusek, John W.. Vanderbilt University; Estados UnidosFil: Hastorf, Christine A.. University of California at Berkeley; Estados Unido

    Using the present to interpret the past: the role of ethnographic studies in Andean archaeology

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    Within Andean research it is common to use ethnographic analogies to aid the interpretation of archaeological remains, and ethnographers and archaeologists have developed shared research in technology, material culture and material practice. Although most of this research does not follow the detailed recording methods of spatial patterning envisioned in earlier formulations of ethnoarchaeology, it has had a profound effect on how archaeology in the region has been interpreted. This paper uses examples from the study of pottery production to address earlier debates about the use of ethnographic analogy, discusses the dangers of imposing an idealised or uniform vision of traditional Andean societies onto earlier periods (‘Lo Andino’) but stresses the benefits of combining ethnographic and archaeological research to explore continuities and changes in cultural practice and regional variations

    Calcul des pertes par courants induits dans les conducteurs statoriques des machines asynchrones sans fer

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    Statoric windings of electrical machines are generally made out of Roebell bars and, less frequently, of twisted conductor bars. The a.c. component of the magnetic field induces eddy currents within each elementary conductor and also induces currents which circulate between different conductors of the same bar. These currents are calculated, in the case of ironless asynchronous machines, using a computer simulation previously developed for such machines [1]. These calculations show that the eddy current losses, and the losses due to the induced circulating currents can always be made negligible with a good choice of the conductors.Les bobinages statoriques des machines sont gĂ©nĂ©ralement constituĂ©s de barres Roebell et plus rarement de barres torsadĂ©es. Le champ magnĂ©tique alternatif auquel ils sont soumis engendre des courants de Foucault locaux et, Ă  l'intĂ©rieur des barres, des courants de circulation entre les diffĂ©rents conducteurs qui la constituent. On calcule ces courants dans le cas des machines sans fer en utilisant la modĂ©lisation des champs prĂ©cĂ©demment mise en place pour ces machines [1]. On montre ainsi que les pertes par courants de Foucault et par courants de circulation peuvent toujours ĂȘtre rendues nĂ©gligeables par un choix appropriĂ© des conducteurs

    Allergies alimentaires rares [Rare food allergies]

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    A limited number of foods explain the majority of food allergies. These allergies can be due to a weak allergenicity (garlic, onion, potato), or a weak (or increasing) exposure to emergent food allergens which can be imported (exotic fruits), or recently introduced (lupin, buckwheat, sesame, inulin) or modified by the industry (lysats, lecithins, traces of antibiotics, caseinates, molds, dust mite). Others are in relation with rarer cross-reactivity food allergy syndrome (Apiaceae-Compositae-mugwort syndrome, egg-bird syndrome, cat epithelium-pork meat syndrome). Others are rarely identified, because the food is masked (pepper, basilic). We illustrate rare cases of food allergy and discuss the diagnostic management which is based on a meticulous patient history. Un nombre restreint d'aliments explique la majorité des allergies alimentaires. Les allergies alimentaires rares sont dues à une faible allergénicité (ail, oignon, pomme de terre) ou à une exposition faible ou croissante à des aliments émergents, importés (fruits exotiques), introduits (lupin, sarrasin, sésame, inuline), ou modifiés par l'industrie (lysats, lécithines, traces d'antibiotiques, caséinates, moisissures, acariens). D'autres sont en relation avec des croisements d'allergÚnes rares (syndrome croisé ombellifÚres-composées-armoise, syndrome oeuf-oiseau, syndrome épithélium de chat-viande de porc). D'autres enfin sont rarement identifiées, car l'allergÚne est masqué (poivre, basilic). Nous décrivons des cas rares illustratifs et rappelons la démarche diagnostique qui s'appuie sur une anamnÚse minutieuse
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