8 resultados para 5400

em CentAUR: Central Archive University of Reading - UK


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The Holocene vegetation history of the Arabian Peninsula is poorly understood, with few palaeobotanical studies to date. At Awafi, Ras al-Khaimah, UAE, a 3.3 m lake sediment sequence records the vegetation development for the period 8500 cal. yr BP to similar to3000 cal. yr BP. delta(13)C isotope, pollen and phytolith analyses indicate that C3 Pooid grassland with a strong woody element existed during the early Holocene (between 8500 and 6000 cal. yr BP) and became replaced by mixed C3 and C4 grasses with a strong C4 Panicoid tall grass element between 5900 and 5400 cal. yr BP. An intense, arid event Occurred at 4100 cal. yr BP when the lake desiccated and was infilled by Aeolian sand. From 4100 cal. yr BP the vegetation was dominated by C4 Chloridoid types and Cyperaceae, suggesting an incomplete vegetation cover and Aeolian dune reactivation owing to increased regional aridity. These data outline the ecosystem dynamics and carbon cycling in response to palaeomon-soon and north-westerly variability during the Holocene. Copyright (C) 2004 John Wiley Sons, Ltd.

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Wavenumber-frequency spectral analysis and linear wave theory are combined in a novel method to quantitatively estimate equatorial wave activity in the tropical lower stratosphere. The method requires temperature and velocity observations that are regularly spaced in latitude, longitude and time; it is therefore applied to the ECMWF 15-year re-analysis dataset (ERA-15). Signals consistent with idealized Kelvin and Rossby-gravity waves are found at wavenumbers and frequencies in agreement with previous studies. When averaged over 1981-93, the Kelvin wave explains approximately 1 K-2 of temperature variance on the equator at 100 hPa, while the Rossby-gravity wave explains approximately 1 m(2)s(-2) of meridional wind variance. Some inertio-gravity wave and equatorial Rossby wave signals are also found; however the resolution of ERA-15 is not sufficient for the method to provide an accurate climatology of waves with high meridional structure.

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In the 1980s, in the midst of the AIDS epidemic, many countries introduced lifetime bans on blood donations by men who had sexual relations with men (MSM). These blanket bans have, recently, begun to be challenged and, as a result, many countries have either relaxed them or completely abolished them. The case under examination (Léger ) is another instance of questioning the legality of such a ban. In particular, in this case, the European Court of Justice was called on to rule on whether a measure such as the French lifetime exclusion from blood donation of the MSM population that was at issue before the referring court is contrary to EU law. The Court ruled that although discriminatory on the ground of sexual orientation, such a ban may be justified in certain circumstances, and left it to the national court to make the final decision. This article seeks to analyse the case and to explain why, in the author’s view, the Court can be accused of—once more—not going far enough in the protection of lesbian, gay and bisexual (LGB) rights.