3,845 research outputs found
Labour Law and Social Insurance in the New Economy: A Debate on the Supiot Report
The debate on this Discussion Paper took place at the London School of Economics on July 8 2000. It was made possible by a grant from DGV of the European Commission. It took place as a special mini-conference during the annual meeting of the Society for the Advancement of Socio-Economics, SASE, hosted by LSE. Translation services were provided by Multilingual Services, and the transcripts have been edited by Hugh Stephenson. All of the participants spoke in a personal capacity and what they said is not necessarily the policy of the organisations from which they come. This Discussion Paper is produced under the 'Future of Trade Unions in Modern Britain' Programme supported by the Leverhulme Trust. The Centre for Economic Performance acknowledges with thanks, the generosity of the Trust. SPEAKERS: Peter Auer Dominique de Calan David Coats Simon Deakin Richard B. Freeman Reiner Hoffmann Renate Hornung-Draus Jane Lewis David Marsden Pamela Meadows Hedva Sarfati Alain Supiot
Carboniferous and Permian magmatism in Scotland
Extensional tectonics to the north of the Variscan Front during the Early Carboniferous generated fault-controlled basins across the British Isles, with accompanying basaltic magmatism. In Scotland Dinantian magmatism was dominantly mildly alkaline-transitional in composition. Tournaisian activity was followed by widespread Visean eruptions largely concentrated within the Scottish Midland Valley where the lava successions, dominantly of basaltic-hawaiitic composition, attained thicknesses of up to 1000 m. Changing stress fields in the late Visean coincided with a change in the nature of the igneous activity; subsequently, wholly basic magmatism persisted into the Silesian. As sedimentary basin fills increased, sill intrusion tended to dominate over lava extrusion. In the Late Carboniferous (Stephanian) a major melting episode, producing large volumes of tholeiitic magma, gave rise to a major dyke swarm and sills across northern England and Scotland. Alkali basaltic magmatism persisted into the Permian, possibly until as late as 250 Ma in Orkney. Geochemical data suggest that the Carboniferous-Permian magmas were dominantly of asthenospheric origin, derived from variable degrees of partial melting of a heterogeneous mantle source; varying degrees of interaction with the lithosphere are indicated. Peridotite, pyroxenite and granulite-facies basic meta-igneous rocks entrained as xenoliths within the most primitive magmas provide evidence for metasomatism of the lithospheric mantle and high-pressure crystal fractionation
Palaeoecological and possible evolutionary effects of early Namurian (Serpukhovian, Carboniferous) glacioeustatic cyclicity
Early Namurian (Serpukhovian, Carboniferous), sedimentary cycles in the Throckley and Rowlands Gill boreholes, near Newcastle upon Tyne, UK, consist of fossiliferous limestones overlain by (usually unfossiliferous) black mudstone, followed by sandstones and often by thin coal seams. Sedimentological and regional geological evidence suggests that the largest are high-amplitude cycles, probably of glacioeustatic origin. 13C (bulk organic matter) delineates marine and non-marine conditions because of the large difference between terrestrial and marine 13C, and indicates that full marine salinity was only intermittent and resulted from glacioeustatic marine transgression superimposed on a background of inundation by freshwater from large rivers, which killed off the marine biota. Palynology suggests that plant groups, including ferns and putative pteridosperms, were affected by changing sea level, and that there is a theoretical possibility of connection between cyclicity and the first appearance of walchiacean conifer-like monosaccate pollen such as Potonieisporites. Long-term terrestrial and marine increasing 13C (organic) may reflect the onset of major glaciation in Gondwana, as there is evidence to suggest that the two are coeval, but no specific mechanism can be suggested to link the trends
Spatio-temporal modelling of extreme storms
A flexible spatio-temporal model is implemented to analyse extreme
extra-tropical cyclones objectively identified over the Atlantic and Europe in
6-hourly re-analyses from 1979-2009. Spatial variation in the extremal
properties of the cyclones is captured using a 150 cell spatial regularisation,
latitude as a covariate, and spatial random effects. The North Atlantic
Oscillation (NAO) is also used as a covariate and is found to have a
significant effect on intensifying extremal storm behaviour, especially over
Northern Europe and the Iberian peninsula. Estimates of lower bounds on minimum
sea-level pressure are typically 10-50 hPa below the minimum values observed
for historical storms with largest differences occurring when the NAO index is
positive.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS766 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Impact of estimation techniques on regression analysis: an application to survey data on child nutritional status in five African countries
This paper illustrates the impact of ignoring survey design and hierarchical structure of survey data when fitting regression models. Data on child nutritional status from Ghana, Malawi, Tanzania, Zambia, and Zimbabwe are analysed using four techniques: ordinary least squares; weighted regression using standard statistical software; regression using specialist software that accounts for the survey design; and multilevel modelling. The impact of ignoring survey design on logistic and linear regression models is examined. The results show bias in estimates averaging between five and 17 per cent in linear models and between five and 22 per cent in logistic regression models. The standard errors are also under-estimated by up to 49 per cent in some countries. Socio-economic variables and service utilisation variables are poorly estimated when the survey design is ignored
A Bayesian framework for verification and recalibration of ensemble forecasts: How uncertain is NAO predictability?
Predictability estimates of ensemble prediction systems are uncertain due to
limited numbers of past forecasts and observations. To account for such
uncertainty, this paper proposes a Bayesian inferential framework that provides
a simple 6-parameter representation of ensemble forecasting systems and the
corresponding observations. The framework is probabilistic, and thus allows for
quantifying uncertainty in predictability measures such as correlation skill
and signal-to-noise ratios. It also provides a natural way to produce
recalibrated probabilistic predictions from uncalibrated ensembles forecasts.
The framework is used to address important questions concerning the skill of
winter hindcasts of the North Atlantic Oscillation for 1992-2011 issued by the
Met Office GloSea5 climate prediction system. Although there is much
uncertainty in the correlation between ensemble mean and observations, there is
strong evidence of skill: the 95% credible interval of the correlation
coefficient of [0.19,0.68] does not overlap zero. There is also strong evidence
that the forecasts are not exchangeable with the observations: With over 99%
certainty, the signal-to-noise ratio of the forecasts is smaller than the
signal-to-noise ratio of the observations, which suggests that raw forecasts
should not be taken as representative scenarios of the observations. Forecast
recalibration is thus required, which can be coherently addressed within the
proposed framework.Comment: 36 pages, 10 figure
A short response-time atomic source for trapped ion experiments
Ion traps are often loaded from atomic beams produced by resistively heated
ovens. We demonstrate an atomic oven which has been designed for fast control
of the atomic flux density and reproducible construction. We study the limiting
time constants of the system and, in tests with , show we can
reach the desired level of flux in 12s, with no overshoot. Our results indicate
that it may be possible to achieve an even faster response by applying an
appropriate one-off heat treatment to the oven before it is used.Comment: 5 pages, 7 figure
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