66 resultados para Last dictatorship
Resumo:
Several large abrupt climate fluctuations during the last glacial have been recorded in Greenland ice cores and archives from other regions. Often these Dansgaard-Oeschger events are assumed to have been synchronous over wide areas, and then used as tie-points to link chronologies between the proxy archives. However, it has not yet been tested independently whether or not these events were indeed synchronous over large areas. Here, we compare Dansgaard-Oeschger-type events in a well-dated record from southeastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, comparisons between proxy archives should be based on independent, non-tuned time-scales. Copyright (C) 2009 John Wiley & Sons, Ltd.
Resumo:
An exceptional specimen of the Late Ordovician mollusc ‘Helminthochiton’ thraivensis Reed, from the Katian of the Lady Burn Starfish Beds, southwest Scotland, preserves gut contents that include nine pelmatozoan ossicles. These are interpreted as including two nodal and five intermodal columnals, and two radice ossicles from the attachment structure. The stem was cyclocyclic and heteromorphic, possibly N212. Radice ossicles were wider than the height of nodals, so radice scars must have encroached onto the latera of adjacent pluricolumnals. These features were compared with the 26 known pelmatozoan taxa from the Lady Burn Starfish Beds. Paracrinoids (one species) and glyptocystitid rhombiferans (six species) were discounted as prey because of their cemented attachment, and incorrect columnal morphology and lack of attachment, respectively. Of 19 species of crinoids, eight are discounted in which the column is pentagonal, tetragonal or unknown. Of the remaining eleven species, only the monobathrid camerate Macrostylocrinus cirrifer Ramsbottom satisfies all criteria for identification of the prey, including heteromorphy and radice scars encroaching adjacent internodals.
Resumo:
The sediments of Like Fimon N Italy contain the first continuous archive of the Late Pleistocene environmental and climate history of the southern Alpine foreland We present here the detailed palynological record of the interval between Termination II and the List Glacial Maximum The age-depth model is obtained by radiocarbon dating in the uppermost part of the record Downward we con elated major forest expansion and contraction events to isotopic events in the Greenland Ice core records via a stepping-stone approach involving intermediate correlation to isotopic events dated by TIMS U/Th in Alpine and Apennine stalagmites and to pollen records from mime cores of the Iberian margin Modelled ages obtained by Bayesian analysis of deposition are thoroughly consistent with actual ages with maximum offset of +/- 1700 years Sharp expansion of broad-leaved temperate forest and of sudden water table rise mark the onset of the Last Interglacial after a treeless steppe phase at the end of penultimate glaciation This event is actually a two-step process which matches the two step rise observed in the isotopic record of the nearby Antro del Corchia stalagmite respectively dated to 132 5 +/- 2 5 and 129 +/- 1 5 ka At the interglacial decline mixed oak forests were replaced by oceanic mixed forests the latter persisting further for 7 ka till the end of the Eemian succession Warm-temperate woody species are still abundant at the Eemian end corroborating a steep gradient between central Europe and the Alpine divide at the inception of the last glacial After a stadial phase marked by moderate forest decline a new expansion of warm broad leaved forests interrupted by minor events and followed by mixed oceanic forests can be identified with the north-alpine Saint Germain I The spread of beech during the oceanic phase is a valuable circumalpine marker The subsequent stadial-interstadial succession lacking the telocratic oceanic phase is also consistent with the evidence at the north alpine foreland The Middle Wurmian (full glacial) is marked by persistence of mixed forests dominated by conifers but with significant lime and other broad leaved species A major Arboreal Pollen decrease is observed at modelled age of 38 7 +/- 0 5 ka (larch expansion and last occurrence of lime) which his been related to Heinrich Event 4 The evidence of afforestation persisting south of the Alps throughout most of MIS 3 contrasts with a boreal and continental landscape known for the northern alpine foreland pointing to a sharp rainfall boundary at the Alpine divide and to southern air circulation This is in agreement with the Alpine paleoglaciological record and is supported by the pressure and rainfall patterns designed by mesoscale paleoclimate simulations Strenghtening the continental high pressure during the full glacial triggered cyclogenesis in the middle latitude eastern Europe and orographic rainfall in the eastern Alps and the Balkanic mountains thus allowing forests development at current sea level altitudes (C) 2010 Elsevier Ltd All rights reserved
Resumo:
This article assesses the dramatic shift in Chilean Supreme Court jurisprudence toward accountability for crimes committed during the dictatorship and sets it within the context of judicial reform and political change. Chile's experience has been identified as emblematic of delayed justice, but an examination of key case law identifies the narrow scope and instability of Supreme Court decision-making. The Court has been uncharacteristically assertive in its application of human rights norms yet vulnerable to external influences. The Chilean example underscores the need for political leadership to address past violations in post-conflict societies. Political inertia impeded justice claims and, as a result, change required significant judicial innovation.
Resumo:
We have modeled the gas phase chemistry of warm molecular material around protostars that is seeded with evaporating grain mantles. We show that the release of simple molecules into the gas drives ion-molecule and neutral chemistries which can account for many of the complex 0-bearing and N-bearing molecules observed in hot cores. Initial grain mantle components and secondary product molecules are identified, and the observational consequences are discussed.