2,915 research outputs found
Terbium-activated heavy scintillating glasses
Tb-activated scintillating glasses with high Ln2O3 (Ln=Gd, Y, Lu) concentration up to 40mol% have been prepared. The effects of Ln3+ ions on the density, thermal properties, transmission and luminescence properties under both UV and X-ray excitation have been investigated. The glasses containing Gd2O3 or Lu2O3 exhibit a high density of more than 6.0g/cm3. Energy transfer from Gd3+ to Tb3+ takes place in Gd-containing glass and as a result the Gd-containing glass shows a light yield 2.5 times higher than the Y-or Lu-containing glass. The Effect of the substitution of fluorine for oxygen on the optical properties was also investigated
The tax-seeking state: Protectionism, taxation and state structures in Germany, Russia, Britain and America, 1870-1914.
The twin processes of "economic development" and "state behaviour'' are explained by the major paradigms through reference to economically "reductionist" methodologies. In particular Marxist and Late Development theories have helped perpetuate this methodology. This thesis provides an alternative framework for understanding the above-mentioned processes. In particular, the "autonomous powers" of the state will form a central approach throughout each chapter. Not only do states have multiple powers, but these vary across different political regime forms. These powers are revealed through an empirical examination of the determination of tariff protectionism as it emerged in Europe in the late 187CK s. The argument will focus on a multi-causal approach. Thus the causal input of economic interest groups will be examined. Although these will form a part of the explanation offered here, they will have less salience than is commonly found in the social science literature. The interests of the state are mainly those connected to the demands of "fiscal accumulation". Overall "state interests" are neither monolithic nor unified. Thus it will not be possible to speak of the state as an "actor". States are not so rational as the term would imply. Moreover, "the state" turns out to be a complex political arena of struggling factions, all vying for exclusivist political power. These autonomous state struggles impacted upon economic development; in this case, tariff protectionism. As well as explaining the rise of protectionism in Germany and Russia, as well as America (chapter 2, 3 and 5), the maintenance of British free trade will be also be explained through the model presented here. In addition, industrialisation in Russia will be explained, also from the approach of statist-economy. This approach will be developed more fully in the final chapter
Combining cosmological datasets: hyperparameters and Bayesian evidence
A method is presented for performing joint analyses of cosmological datasets,
in which the weight assigned to each dataset is determined directly by it own
statistical properties. The weights are considered in a Bayesian context as a
set of hyperparameters, which are then marginalised over in order to recover
the posterior distribution as a function only of the cosmological parameters of
interest. In the case of a Gaussian likelihood function, this marginalisation
may be performed analytically. Calculation of the Bayesian evidence for the
data, with and without the introduction of hyperparameters, enables a direct
determination of whether the data warrant the introduction of weights into the
analysis; this generalises the standard likelihood ratio approach to model
comparison. The method is illustrated by application to the classic toy problem
of fitting a straight line to a set of data. A cosmological illustration of the
technique is also presented, in which the latest measurements of the cosmic
microwave background power spectrum are used to infer constraints on
cosmological parameters.Comment: 12 pages, 6 figures, submitted to MNRA
Bayesian model comparison applied to the Explorer-Nautilus 2001 coincidence data
Bayesian reasoning is applied to the data by the ROG Collaboration, in which
gravitational wave (g.w.) signals are searched for in a coincidence experiment
between Explorer and Nautilus. The use of Bayesian reasoning allows, under well
defined hypotheses, even tiny pieces of evidence in favor of each model to be
extracted from the data. The combination of the data of several experiments can
therefore be performed in an optimal and efficient way. Some models for
Galactic sources are considered and, within each model, the experimental result
is summarized with the likelihood rescaled to the insensitivity limit value
(`` function''). The model comparison result is given in in terms of
Bayes factors, which quantify how the ratio of beliefs about two alternative
models are modified by the experimental observationComment: 16 pages, 4 figures. Presented at the GWDAW2002 conference, held in
Kyoto on Dec.,2002. This version includes comments by the referees of CQG,
which has accepted the paper for pubblication in the special issue of the
conference. In particular, note that in Eq. 12 there was a typeset error. As
suggested by one of the referees, a uniform prior in Log(alpha) has also been
considere
Cognitive and social factors in the development of infants with Down syndrome
Infants and young children with Down syndrome can be engaging and affectionate. It seems that in the early months of life their personal relations may be relatively 'spared' the effects of limitations in their capacities for information-processing. Yet how far is this the case as development proceeds? In this paper we discuss some ways in which social and cognitive development interact and mutually influence one another over the first year or so of life, and present preliminary findings from a longitudinal study of infants with and without Down syndrome. The evidence suggests that the development of 'triadic'(person-person-world) social interactions may be affected by limited information-processing capacities in infants with Down syndrome, through a complex socially-mediated developmental trajectory
To Trust or Not to Trust? Developing Trusted Digital Spaces through Timely Reliable and Personalized Provenance
Organizations are increasingly dependent on data stored and processed by distributed, heterogeneous services to make
critical, high-value decisions. However, these service-oriented computing environments are dynamic in nature and are becoming
ever more complex systems of systems. In such evolving and dynamic eco-system infrastructures, knowing how data was derived
is of significant importance in determining its validity and reliability. To address this, a number of advocates and theorists postulate
that provenance is critical to building trust in data and the services that generated it as it provides evidence for data consumers to
judge the integrity of the results. This paper presents a summary of the STRAPP (trusted digital Spaces through Timely Reliable
And Personalised Provenance) project, which is designing and engineering mechanisms to achieve a holistic solution to a number
of real-world service-based decision-support systems
Pleasure and meaningful discourse: an overview of research issues
The concept of pleasure has emerged as a multi-faceted social and cultural phenomenon in studies of media audiences since the 1980s. In these studies different forms of pleasure have been identified as explaining audience activity and commitment. In the diverse studies pleasure has emerged as a multi-faceted social and cultural concept that needs to be contextualized carefully. Genre and genre variations, class, gender, (sub-)cultural identity and generation all seem to be instrumental in determining the kind and variety of pleasures experienced in the act of viewing. This body of research has undoubtedly contributed to a better understanding of the complexity of audience activities, but it is exactly the diversity of the concept that is puzzling and poses a challenge to its further use. If pleasure is maintained as a key concept in audience analysis that holds much explanatory power, it needs a stronger theoretical foundation. The article maps the ways in which the concept of pleasure has been used by cultural theorists, who have paved the way for its application in reception analysis, and it goes on to explore the ways in which the concept has been used in empirical studies. Central to our discussion is the division between the âpublic knowledgeâ and the âpopular cultureâ projects in reception analysis which, we argue, have major implications for the way in which pleasure has come to be understood as divorced from politics, power and ideology. Finally, we suggest ways of bridging the gap between these two projects in an effort to link pleasure to the concepts of hegemony and ideology
Velocity Field Statistics in Star-Forming Regions. I. Centroid Velocity Observations
The probability density functions (pdfs) of molecular line centroid velocity
fluctuations and fluctuation differences at different spatial lags are
estimated for several nearby molecular clouds with active internal star
formation. The data consist of over 75,000 CO line profiles divided
among twelve spatially and/or kinematically distinct regions. Although three
regions (all in Mon R2) appear nearly Gaussian, the others show strong evidence
for non-Gaussian, often nearly exponential, centroid velocity pdfs, possibly
with power law contributions in the far tails. Evidence for nearly exponential
centroid pdfs in the neutral HI component of the ISM is also presented, based
on older optical and radio observations. These results are in contrast to pdfs
found in isotropic incompressible turbulence experiments and simulations.
Furthermore, no evidence is found for the scaling of difference pdf kurtosis
with Reynolds number which is seen in incompressible turbulence, and the
spatial distribution of high-amplitude velocity differences shows little
indication of the filamentary appearance predicted by decay simulations
dominated by vortical interactions. The variation with lag of the difference
pdf moments is presented as a constraint on future simulations.Comment: LaTeX, 23 pages, with 15 Figures included separately as gif image
files. Refereed/revised version accepted to the Astrophysical Journal. A
complete (but much larger) postscript version is available from
http://ktaadn.gsfc.nasa.gov/~miesc
Behaviour of infants with Down syndrome and their mothers in the still-face procedure
There has been limited study of how the constitutional characteristics of infants with Down syndrome (DS) influence the patterning of their relations with caregivers. To assess natural and perturbed interactions between infants with DS and their mothers, we tested ten 6-month-old infants with DS and 20 typically developing (TD) 4-month-old of similar mental age. Participants were videotaped with their mothers in a natural face-to-face interaction, a brief period when the mothers adopted a still-face, and a subsequent reengagement phase. There was little to distinguish the infants in the initial phase of natural interaction, but the mothers of infants with DS were more likely to show assertive warmth, and unlike in the case of mothers of TD infants, high maternal directiveness tended to be associated with lower levels of infant looking and lack of fussing. During the still-face episode, infants of both groups showed reduced looking and smiling, although infants with DS tended to show lower levels of fussing and fewer in this group showed fussing in the reengagement phase. Therefore DS infants were somewhat similar to TD infants of comparable mental age in being responsive to the still-face procedure, but showed indications of group differences in intense emotional reactivity
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