Evidence for nonlinear diffusive shock acceleration of cosmic-rays in the 2006 outburst of the recurrent nova RS Ophiuchi

Spectroscopic observations of the 2006 outburst of the recurrent nova RS Ophiuchi at both infrared (IR) and X-ray wavelengths have shown that the blast wave has decelerated at a higher rate than predicted by the standard test-particle adiabatic shock-wave model. Here we show that the observed evolution of the nova remnant can be explained by the diffusive shock acceleration of particles at the blast wave and the subsequent escape of the highest energy ions from the shock region. Nonlinear particle acceleration can also account for the difference of shock velocities deduced from the IR and X-ray data. The maximum energy that accelerated electrons and protons can have achieved in few days after outburst is found to be as high as a few TeV. Using the semi-analytic model of nonlinear diffusive shock acceleration developed by Berezhko & Ellison, we show that the postshock temperature of the shocked gas measured with RXTE/PCA and Swift/XRT imply a relatively moderate acceleration efficiency.Comment: Accepted for publication in ApJ

A Measure of Core Inflation in the UK

We develop a measure of core inflation in the UK over the period January1987 - December 1998, following the work of Bryan and Cecchetti (1996),Bryan, Cecchetti and Wiggins (1997) and Roger (1997). Disaggregation is into85 price categories. Given the high kurtosis of the price change distribution over this period, a trimmed mean is a more robust estimator of core inflation than other published measures such as the RPIX widely used in the UK, in particular by the Bank of England when targeting inflation. We discuss the relative advantages of our measure of core inflation, with emphasis on the determination of an optimal trimming point and on the analysis of the products whose price changes are excluded from our measure in each time period. The resulting measure appears well behaved, but differs noticeably from a number of published measures.

Modelling Ireland’s Exchange Rates - From EMS to EMU

This paper attempts to model the nominal and real exchange rate for Ireland, relative to Germany and the UK from 1975 to 2003. It offers an overview of the theory of purchasing power parity (Ppp), focusing particularly on likely sources of nonlinearity. Potential difficulties in placing the analysis in the standard I(1)/I(0) framework are highlighted and comparisons with previous Irish studies are made. Tests for fractional integration and nonlinearity, including random field regressions, are discussed and applied. The results obtained highlight the likely inadequacies of the standard cointegration and Star approaches to modelling, and point instead to multiple structural changes models. Using this approach, both bilateral nominal exchange rates are effectively modelled, and in the case of Ireland and Germany, Ppp is found to be valid not only in the long run, but also in the medium term.Purchasing power parity; fractional Dickey-Fuller tests; smooth transition autoregression; random field regression; multiple structural changes models

Job quality in Europe

Promoting job quality and gender equality are objectives of the European Employment Strategy (EES) in spite of a downgrading of the attention given to both in the revised employment guidelines and the re-launch of the Lisbon Process. However, advances on both of these objectives may be important complements to the employment rate targets of the EES, as access to good quality jobs for both sexes is likely to help sustain higher employment rates. While the European Commission has a broad view of the concept of job quality in practice, it relies on a selection of labour market type indicators that say little about the quality of the actual jobs people do. Using data from the 2005 European Working Conditions survey, we analyse job quality along three dimensions: job content, autonomy and working conditions. We conclude that gender and occupational status, along with other job characteristics such as working time and sector, have more influence on an individual’s job quality than the country or ‘national model’ they are situated in. Our results also demonstrate the value of developing indicators of job quality that are both gender sensitive and derived at the level of the job rather than the labour market in order to advance EU policy and academic debate on this topic

Infectious intestinal disease : do we know it all?

Infectious intestinal disease (IID), with associated high morbidity and considerable mortality worldwide, causes a wide spectrum of illness. This ranges from mild discomfort to illness with severe complications. The economic burden from direct and indirect costs may be high. It is acquired by oral ingestion of micro-organisms which are transmitted from person to person; via food or water or through contact with animals or contaminated objects. Viruses are the commonest cause in developed countries. In Malta, medical practitioners and laboratories are the main source of data on IID. However, under-reporting is a problem. In order to fill in the lacunae in information on the disease burden, population-based-studies are required. Along with other countries, Malta has embarked on a number of studies to describe and quantify under-reporting of IID. This may assist in strengthening the surveillance system which, in combination with other measures, should result in an improvement of the control of IID.peer-reviewe

Laboratory surveillance of communicable diseases : enteric pathogens

Laboratories represent a crucial link in the surveillance chain. Since only a small proportion of cases of enteric infections are asked to submit a stool sample, one needs to assess the practices for testing for enteric pathogens and their notification practices. Five local laboratories participated in this study. This included a description of the laboratory practices; capacity for stool sample analysis; awareness of the notification system and the factors which could improve the system at laboratory level.peer-reviewe

Towards predicting post-editing productivity

Machine translation (MT) quality is generally measured via automatic metrics, producing scores that have no meaning for translators who are required to post-edit MT output or for project managers who have to plan and budget for transla- tion projects. This paper investigates correlations between two such automatic metrics (general text matcher and translation edit rate) and post-editing productivity. For the purposes of this paper, productivity is measured via processing speed and cognitive measures of effort using eye tracking as a tool. Processing speed, average fixation time and count are found to correlate well with the scores for groups of segments. Segments with high GTM and TER scores require substantially less time and cognitive effort than medium or low-scoring segments. Future research involving score thresholds and confidence estimation is suggested

Nonlinearity as an Explanation of the Forward Exchange Rate Anomaly

This paper shows that nonlinearity can provide an explanation for the forward exchange rate anomaly (Fama, 1984). Using sterling-Canadian dollar data, and modelling nonlinearity of unspecified form by means of a random field, we find strong evidence of time-wise nonlinearity and, significantly, obtain parameter estimates that conform with theory to a high degree of precision: the anomaly disappears.Forward exchange rate anomaly; nonlinearity; random field regression

Is turbulent mixing a self convolution process ?

Experimental results for the evolution of the probability distribution function (PDF) of a scalar mixed by a turbulence flow in a channel are presented. The sequence of PDF from an initial skewed distribution to a sharp Gaussian is found to be non universal. The route toward homogeneization depends on the ratio between the cross sections of the dye injector and the channel. In link with this observation, advantages, shortcomings and applicability of models for the PDF evolution based on a self-convolution mechanisms are discussed.Comment: 4 page

Exact zero-point energy shift in the e⊗(n E)e\otimes (n~E), t⊗(n H)t\otimes (n~H) many modes dynamic Jahn-Teller systems at strong coupling

We find the exact semiclassical (strong coupling) zero-point energy shifts applicable to the $e\otimes (n E)$ and $t\otimes (n H)$ dynamic Jahn-Teller problems, for an arbitrary number $n$ of discrete vibrational modes simultaneously coupled to one single electronic level. We also obtain an analytical formula for the frequency of the resulting normal modes, which has an attractive and apparently general Slater-Koster form. The limits of validity of this approach are assessed by comparison with O'Brien's previous effective-mode approach, and with accurate numerical diagonalizations. Numerical values obtained for $t\otimes (n H)$ with $n =8$ and coupling constants appropriate to C$_{60}^-$ are used for this purpose, and are discussed in the context of fullerene.Comment: 20 pages, 4 ps figure