853 resultados para Ovid, 43 B.C.-17 or 18 A.D.


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orty-eight surface sediment samples from the southeast (SE) Pacific (25-53°S) are investigated for the determination of the spatial distribution of organic-walled dinoflagellate cysts along the western South American continental margin. Fifty-five different taxa are recorded and reflect oceanic or coastal assemblages. The oceanic assemblages are characterised by low cyst concentrations and the dominance of autotrophs, while the coastal assemblages generally contain a higher number of cysts, which are mainly produced by heterotrophic species. Highest cyst concentrations are observed in the active upwelling system offshore Concepción (35-37°S). Brigantedinium spp., Echinidinium aculeatum, Echinidinium granulatum/delicatum and cysts of Protoperidinium americanum dominate assemblages related to upwelling. Echinidinium aculeatum appears to be the best indicator for the presence of all year round active upwelling cells. Other protoperidinioid cysts may also occur in high relative abundances in coastal regions outside active upwelling systems, if the availability of nutrients, co-responsible for the presence/absence of their main food sources such as diatoms and other protists, is sufficient. The importance of nutrient availability as a determining environmental variable influencing cyst signals on a regional scale (SE Pacific) is demonstrated through statistical analyses of the data. Because of the importance of nutrients, uncertainties about the outcomes of quantitative sea-surface temperature (SST) reconstructions (Modern Analogue Technique) based on dinoflagellate cysts may arise, since no interaction between different hydrographical variables is considered in this approach. The combination of the SE Pacific surface sample dataset with other published cyst data from the Southern Hemisphere resulted in a database which includes 350 samples: the 'SH350 database'. This database is used to test the accuracy of the quantitative reconstructions by calculating and comparing the estimated versus observed values for each site. An attempt to perform quantitative SST reconstructions on the last 25 cal ka of site ODP1233 (41°S; 74°27'W) is made and again stresses the importance of other environmental variables such as nutrient availability in determining the dinoflagellate cyst assemblages.

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The Kara Sea is an area uniquely suitable for studying processes in the river-sea system. This is a shallow sea, into which two great Siberian rivers, Yenisei and Ob, flow. From 1995 to 2003, the sea was studied by six international expeditions onboard the R/V Akademik Boris Petrov. This publication summarizes the results obtained, within the framework of this project, at the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. Various hydrogeochemical parameters, concentrations and isotopic composition of organic and carbonate carbon of the sediments, plankton, particulate organic matter, hydrocarbons, and dissolved CO2 were examined throughout the whole sea area at more than 200 sites. The d13C varies from -22 and -24 per mil where Atlantic waters enter the Kara Sea and in the north-eastern part of the water area to -27 per mil in the Yenisei and Ob estuaries. The value of d13C of the plankton is only weakly correlated with the d13C of the organic matter from the sediments and is lower by as much as 3-4 per mil. The paper presents the results obtained from a number of meridional river-sea profiles. It was determined from the relations between the isotopic compositions of plankton and particulate matter that the river waters carry material consisting of 70% detrital-humus matter and 30% planktonogenic material in the river part, and the material contained in the offshore waters consists of 30% terrigenous components, with the contribution of bioproducers amounting to 70%. The carbon isotopic composition of the plankton ranges from -29 to -35 per mil in the riverine part, from -28 to -27 per mil in the estuaries, and from -27.0 to -25 per mil in the marine part. The relative lightness of the carbon isotopic composition of plankton in Arctic waters is explained by the temperature effect, elevated CO2 concentrations, and long-distance CO2 supply to the sea with river waters. The data obtained on the isotopic composition of CO2 in the surface waters of the Kara Sea were used to map the distribution of d13C. The complex of hydrocarbon gases extracted from the waters included methane, C2-C5, and unsaturated C2=-C4= hydrocarbons, for which variations in the concentrations in the waters were studied along river-estuary-sea profiles. The geochemistry of hydrocarbon gases in surface fresh waters is characterized by comparable concentrations of methane (0.3-5 µl/l) and heavier hydrocarbons, including unsaturated ones. Microbiological methane with d13C from -105 to -90 per mil first occurs in the sediments at depths of 40-200 cm. The sediments practically everywhere display traces of methane oxidation in the form of a shift of the d13C of methane toward higher values and the occurrence of autogenic carbonate material, including ikaite, enriched in the light isotope. Ikaite (d13C from -25 to -60 per mil) was found and examined in several profiles. The redox conditions in the sediments varied from normal in the southern part of the sea to highly oxidized along the Novaya Zemlya Trough. Vertical sections through the sediments of the latter exemplify the complete suppression of the biochemical activity of microorganisms. Our data provide insight into the biogeochemistry of the Kara Sea and make it possible to specify the background values needed for ecological control during the future exploration operations and extraction of hydrocarbons in the Kara Sea.

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Among the Siberian shelf seas the Kara Sea is most strongly influenced by riverine runoff with nearly 1500 km fresh water discharge per year. This fresh water, discharged mainly by Ob and Yenisei, contains about 3.1 * 106 and 4.6 * 106 tons of total organic carbon per year, respectively (Gordeev et al. 1996). Little is known about the relevance of this organic material for biological communities, neither for the Kara Sea nor for the adjacent deep basins of the central Arctic Ocean. Aiming at elucidating the fate of fluvial matter transported from the rivers via estuaries into the central Arctic Ocean and the relative importance of marine organic matter being produced such information is crucial. Here we present calculations on the organic carbon demand of the Kara Sea macrozoobenthos based on measured biomass (total wet weight [ww] per 0.25 m ) from quantitative box corer samples and empirical relationships between biomass, annual production, annual respiration, and carbon remineralisation. This bottom-up approach may serve as a first estimate of the carbon remineralization potential of a given zoobenthos community (or area) as long as no data on in situ respiration rates are available. Our data basis comprises 54 stations sampled in summer seasons 1997, 1999 and 2000 in the Kara Sea at water depths between 10 and 68 m. The geographical area represented by stations analysed covers roughly 178 000 km**2, which is about one fifth of the total Kara Sea area. In this area, 290 species of invertebrate macrozoobenthos were identified with polychaeta, Crustacea, mollusca and echinodermata being the most abundant. For all stations analysed, mean biomass values ranged between 4.3 and 778.1 g ww/m**2 with organic carbon demands between 3.5 and 43.2 mg C/m**2/d. For the area of 178 000 km2 a preliminary total consumption of 1.4 * 10**6t Corg/y (equivalent to 21.5 mg C/m**2/d) was calculated for the macrozoobenthos. An extrapolation of our data would lead to an annual carbon demand of about 5-7 * 106 t for the whole Kara Sea macrozoobenthos (or 15.5-21.7 mg C/m2/d).

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Transfer of organic carbon (OC) from the terrestrial to the oceanic carbon pool is largely driven by riverine and aeolian transport. Before transport, however, terrigenous organic matter can be retained in intermediate terrestrial reservoirs such as soils. Using compound-specific radiocarbon analysis of terrigenous biomarkers their average terrestrial residence time can be evaluated. Here we show compound-specific radiocarbon (14C) ages of terrigenous biomarkers and bulk 14C ages accompanied by geochemical proxy data from core top samples collected along transects in front of several river mouths in the Black Sea. 14C ages of long chain n-alkanes, long chain n-fatty acids and total organic carbon (TOC) are highest in front of the river mouths, correlating well with BIT (branched and isoprenoid tetraether) indices, which indicates contribution of pre-aged, soil-derived terrigenous organic matter. The radiocarbon ages decrease further offshore towards locations where organic matter is dominated by marine production and aeolian input potentially contributes terrigenous organic matter. Average terrestrial residence times of vascular plant biomarkers deduced from n-C29+31 alkanes and n-C28+30 fatty acids ages from stations directly in front of the river mouths range from 900 ± 70 years to 4400 ± 170 years. These average residence times correlate with size and topography in climatically similar catchments, whereas the climatic regime appears to control continental carbon turnover times in morphologically similar drainage areas of the Black Sea catchment. Along-transect data imply petrogenic contribution of n-C29+31 alkanes and input via different terrigenous biomarker transport modes, i.e., riverine and aeolian, resulting in aged biomarkers at offshore core locations. Because n-C29+31 alkanes show contributions from petrogenic sources, n-C28+30 fatty acids likely provide better estimates of average terrestrial residence times of vascular plant biomarkers. Moreover, sedimentary n-C28 and n-C30 fatty acids appear clearly much less influenced by autochthonous sources than n-C24 and n-C26 fatty acids as indicated by increasing radiocarbon ages with increasing chain-length and are, thus, more representative as vascular plant biomarkers.

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Several vertebrae of a sauropterygian specimen have been recovered in Fuencaliente de Medinaceli (Soria Province, Castilla y León, Spain). The remains come from Middle–Upper Triassic Muschelkalk Facies. This finding represents the first documented evidence of a Triassic tetrapod in Castilla y León. The vertebrae belong to Nothosaurus, a sauropterygian genus found in Europe, Middle East, North of Africa and China. This genus is poorly-known in the Iberian record. The new remains constitute the first evidence of the species Nothosaurus giganteus, or a related taxon, in the Iberian Peninsula. This study reveals the occurrence of at least two species of the sauropterygian Nothosaurus in the Spanish record.

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Research on women’s employment has proliferated over recent decades, often under a perspective that conceptualizes female labour market activity as independent of male presences and absences in the productive and reproductive spheres. In the face of these approaches, the article argues the need to focus on the couple as the unit of analysis of work-life articulation. After referring to the main theoretical arguments that, from a gender perspective within labour studies, have pointed out the relevance of placing the household as the central space for the analysis of the sexual division of labour, the article reviews different empirical contributions that have incorporated such perspective in the international literature. Next, the state of the art in the Spanish literature is presented, before arguing the desirability of applying such framework of analysis to the study of employment and care work in Spanish households, which are at present undergoing major transformations.

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This paper examines the social dynamics of electronic exchanges in the human services, particularly in social work. It focuses on the observable effects that email and texting have on the linguistic, relational and clinical rather than managerial aspects of the profession. It highlights how electronic communication is affecting professionals in their practice and learners as they become acculturated to social work. What are the gains and losses of the broad use of electronic devices in daily lay and professional, verbal and non-verbal communication? Will our current situation be seriously detrimental to the demeanor of future practitioners, their use of language, and their ability to establish close personal relationships? The paper analyzes social work linguistic and behavioral changes in light of the growth of electronic communication and offers a summary of merits and demerits viewed through a prism emerging from Baron’s (2000) analysis of human communication.

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La reafirmación del modelo político-administrativo ciudadano tras la fase arcaica colonial abre una nueva etapa de prosperidad en la antigua fundación tiria. El esplendor de Gadir en el s. V a.C. se refleja en los textos clásicos y en los hallazgos arqueológicos y, sin embargo, nuestros conocimientos sobre el desarrollo histórico de la ciudad de época púnica son muy limitados. El horizonte arcaico comienza a esclarecerse tras los hallazgos del Teatro Cómico que han sacado a la luz los restos de la fundación tiria y, sin embargo, la ciudad posterior continúa siendo una gran incógnita. ¿A qué lugar se traslada la población una vez que se abandona el asentamiento primitivo? ¿Quiénes son los individuos enterrados en los excepcionales sarcófagos antropoides? ¿Qué relación jerárquica existe entre el asentamiento insular y los situados en tierra firme? ¿Qué papel jugó la industria y comercialización de las salazones? Los interrogantes planteados son múltiples y no hacen más que evidenciar la incapacidad del paradigma tradicional para explicar el desarrollo histórico de la Gadir postcolonial y la necesidad de buscar nuevos modelos interpretativos.

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Research surrounding the transition from II to I millennium cal BC in Eastern Iberian Peninsula has a large and extensive tradition of investigation. However, the chances to do research on this historical process have been limited by the lack of a well contextualized and dated stratigraphic sequence. For this reason, recent studies in this topic have followed the periodic proposals which were developed in closer regions and areas, especially in the South East and North East of the Peninsula. The investigation perspective about the Late Bronze in Eastern Iberian has however now improved, with the development of several archaeological investigations, the increase in the number of sites being dated and more recent studies into the region helping to bring about this change. As such, it is now in the correct state to be able to propose a new periodization and delve into the changes which occurred in the transition between 1500 and 725 cal BC.

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Este trabajo presenta la reelaboración de un modelo de producción de textos escritos, publicado por el Grupo Didactext en 2003. Se sitúa en un marco sociocognitivo, lingüístico y didáctico, y está concebido desde la interacción de tres dimensiones simbolizadas por círculos concéntricos recurrentes. El primer círculo corresponde al ámbito cultural: las diversas esferas de la praxis humana en las que está inmersa toda actividad de composición escrita. El segundo se refiere a los contextos de producción, de los que forman parte el contexto social, el situacional, el físico, la audiencia y el medio de composición. El tercer círculo corresponde al individuo, en el que se tiene en cuenta el papel de la memoria en la producción de un texto desde el enfoque sociocultural, la motivación, las emociones y las estrategias cognitivas y metacognitivas, dentro de las cuales se conciben seis unidades funcionales que actúan en concurrencia: acceso al conocimiento, planificación, redacción, revisión y reescritura, edición, y presentación oral. La orientación didáctica se interesa por la enseñanza y el aprendizaje de la escritura académica en las aulas, así como por la investigación de la escritura en contextos de educación.

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Quintus Curtius found in his sources a speech where a Scythian censured Alexander, followed by the King’s reply. Curtius drastically abridged this second discourse in order to highlight the criticism of the Macedonian. The Scythian’s words have a striking rhetorical language and some allusions taken from Greek literature, in addition to possible indirect references to Caligula. Curtius declares that he follows his source word-for-word aiming to justify these inconsistencies, but also trying to hide the manipulations he has done to achieve his own narrative purposes.

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La causalité est une des notions les plus fondamentales de la vie humaine. La vulgarisation scientifique se base sur l’établissement fréquent de relations causales par le truchement d'indices linguistiques. Ainsi, la causalité y est perceptible à l'aide de marques explicites, se manifestant au niveau lexical. Dans de nombreuses situations, afin de valider la relation causale, il faut récupérer des termes plus ou moins explicites qui apparaissent au niveau morphosyntaxique. Viennent enfin les procédés implicites d’expression de la cause ou "la causalité non marquée" linguistiquement.  

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This paper focuses on two basic issues: the anxiety-generating nature of the interpreting task and the relevance of interpreter trainees’ academic self-concept. The first has already been acknowledged, although not extensively researched, in several papers, and the second has only been mentioned briefly in interpreting literature. This study seeks to examine the relationship between the anxiety and academic self-concept constructs among interpreter trainees. An adapted version of the Foreign Language Anxiety Scale (Horwitz et al., 1986), the Academic Autoconcept Scale (Schmidt, Messoulam & Molina, 2008) and a background information questionnaire were used to collect data. Students’ t-Test analysis results indicated that female students reported experiencing significantly higher levels of anxiety than male students. No significant gender difference in self-concept levels was found. Correlation analysis results suggested, on the one hand, that younger would-be interpreters suffered from higher anxiety levels and students with higher marks tended to have lower anxiety levels; and, on the other hand, that younger students had lower self-concept levels and higher-ability students held higher self-concept levels. In addition, the results revealed that students with higher anxiety levels tended to have lower self-concept levels. Based on these findings, recommendations for interpreting pedagogy are discussed.

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Vitamin D insufficiency and deficiency have been associated with an increased risk of adverse pregnancy outcomes. Controversy remains as findings have been inconsistent between disparate populations. The aim of this study was to investigate the relationship between vitamin D status and pregnancy outcomes in a large, prospective pregnancy cohort. 25-Hydroxyvitamin D concentration was analysed in serum samples collected at 15 weeks of gestation from 1710 New Zealand women participating in a large, observational study. Associations between vitamin D status and pre-eclampsia, preterm birth, small for gestational age (SGA) and gestational diabetes were investigated. The mean 25-hydroxyvitamin D concentration was 72·9 nmol/l. In all, 23 % had 25-hydroxyvitamin D concentrations <50 nmol/l, and 5 % of participants had concentrations <25 nmol/l. Women with 25-hydroxyvitamin D concentrations <75 nmol/l at 15 weeks of gestation were more likely to develop gestational diabetes mellitus than those with concentrations >75 nmol/l (OR 2·3; 95 % CI 1·1, 5·1). However, this effect was not significant when adjustments were made for BMI and ethnicity (OR 1·8; 95 % CI 0·8, 4·2). 25-Hydroxyvitamin D concentration at 15 weeks was not associated with development of pre-eclampsia, spontaneous preterm birth or SGA infants. Pregnancy complications were low in this largely vitamin D-replete population.

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El objetivo de este trabajo fue analizar la construcción social del conocimiento en Actividad física desde dos planteamientos teóricos de la salud centrando el análisis en la relación con la imagen corporal y las condiciones de vida. Se trata de un estudio teórico desde el análisis de contenido de corte narrativo de 98 artículos desarrollado en cinco etapas a través de: rastreo de documentos en bases de datos en el periodo 2000-2014, revisión de artículos, y análisis y hallazgos de significados, sentidos o contenidos. Como hallazgo importante se puede mencionar que en la literatura científica relacionada con la triada Actividad física-imagen corporal-condiciones de vida predomina la construcción del conocimiento a partir de modelos hegemónicos y dominantes que priorizan la intensidad, la frecuencia y el tiempo dedicado a la AF, la estandarización en la comparación de la apariencia física y la medición de elementos materiales en el modo de vivir de las personas, principalmente desde el abordaje de los determinantes sociales de la salud. Se concluye que es necesario revisar las poblaciones que incluyendo en los estudios al estar concentrados el conocimiento en solo unos grupos; así como se hace explícita la necesidad de revisar cuales son los aportes de la Educación Física y otras disciplinas (ciencias sociales) para una mayor comprensión teórica y práctica de la AF.