Confidence intervals for posterior intercepts, with application to the PIAAC literacy survey.

For variance component models, it is often the posterior estimate of the random effect (‘posterior intercept’) rather than the estimate of the fixed effect parameters, which is of main interest. This is the case, for instance, when ranking region–wise mortality rates (where the crude, regional rates are unreliable due to small observed counts) or for the construction of educational league tables from complex sample surveys. However, in order to be able to decide whether two cluster–level units can actually be distinguished, it is clear that one needs a measure of variability of these posterior intercepts. We present an exploration of methods to address this issue which appears to be still undeveloped in the context of the model class considered

On the construction of high-order force gradient algorithms for integration of motion in classical and quantum systems

A consequent approach is proposed to construct symplectic force-gradient algorithms of arbitrarily high orders in the time step for precise integration of motion in classical and quantum mechanics simulations. Within this approach the basic algorithms are first derived up to the eighth order by direct decompositions of exponential propagators and further collected using an advanced composition scheme to obtain the algorithms of higher orders. Contrary to the scheme by Chin and Kidwell [Phys. Rev. E 62, 8746 (2000)], where high-order algorithms are introduced by standard iterations of a force-gradient integrator of order four, the present method allows to reduce the total number of expensive force and its gradient evaluations to a minimum. At the same time, the precision of the integration increases significantly, especially with increasing the order of the generated schemes. The algorithms are tested in molecular dynamics and celestial mechanics simulations. It is shown, in particular, that the efficiency of the new fourth-order-based algorithms is better approximately in factors 5 to 1000 for orders 4 to 12, respectively. The results corresponding to sixth- and eighth-order-based composition schemes are also presented up to the sixteenth order. For orders 14 and 16, such highly precise schemes, at considerably smaller computational costs, allow to reduce unphysical deviations in the total energy up in 100 000 times with respect to those of the standard fourth-order-based iteration approach.Comment: 23 pages, 2 figures; submitted to Phys. Rev.

Standardisation of rates using logistic regression: a comparison with the direct method

<p>Abstract</p> <p>Background</p> <p>Standardisation of rates in health services research is generally undertaken using the direct and indirect arithmetic methods. These methods can produce unreliable estimates when the calculations are based on small numbers. Regression based methods are available but are rarely applied in practice. This study demonstrates the advantages of using logistic regression to obtain smoothed standardised estimates of the prevalence of rare disease in the presence of covariates.</p> <p>Methods</p> <p>Step by step worked examples of the logistic and direct methods are presented utilising data from BETS, an observational study designed to estimate the prevalence of subclinical thyroid disease in the elderly. Rates calculated by the direct method were standardised by sex and age categories, whereas rates by the logistic method were standardised by sex and age as a continuous variable.</p> <p>Results</p> <p>The two methods produce estimates of similar magnitude when standardising by age and sex. The standard errors produced by the logistic method were lower than the conventional direct method.</p> <p>Conclusion</p> <p>Regression based standardisation is a practical alternative to the direct method. It produces more reliable estimates than the direct or indirect method when the calculations are based on small numbers. It has greater flexibility in factor selection and allows standardisation by both continuous and categorical variables. It therefore allows standardisation to be performed in situations where the direct method would give unreliable results.</p

Symbolic-Numeric Methods for Nonlinear Integro-Differential Modeling

International audienceThis paper presents a proof of concept for symbolic and numeric methods dedicated to the parameter estimation problem for models formulated by means of nonlinear integro-differential equations (IDE). In particular, we address: the computation of the model input-output equation and the numerical integration of IDE systems

The development of rule-governed behaviour

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Περιβαλλοντικές επιπτώσεις απόρριψης βιομηχανικών αποβλήτων στην περιοχή των εκβολών της λεκάνης του Ασωπού(Οινόφυτα-Συκάμινο-Ωροπός-Χαλκούτσι)

90 σ.Στην παρούσα διπλωματική εργασία εξετάζουμε το ιστορικό του προβλήματος της ρύπανσης του ποταμού Ασωπού, μελετάμε τις περιβαλλοντικές και οικονομικές επιπτώσεις στην ευρεία περιοχή του νότιου Ευβοϊκού κόλπου καθώς επίσης και τις σοβαρές επιπτώσεις του εξασθενούς χρωμίου, και γενικότερα των βαρέων μετάλλων και των ιόντων, στην υγεία του πληθυσμού. Επίσης παραθέτουμε πληθώρα παλαιών μετρήσεων και αναλύσεων των ρυπαντών του Ασωπού ποταμού και τις συγκρίνουμε με τις τωρινές μας μετρήσεις. Οι μετρήσεις μας γίνανε με τις μεθόδους των φασματομετριών UV-VIS και AAS. Παραθέτουμε ενδεικτικό αριθμό βιομηχανιών της περιοχής και τον τρόπο αντίδρασης των κατοίκων μέσα από οργανωμένες και συσπειρωμένες προσπάθειες. Ακόμα βλέπουμε απαντήσεις σε ερωτηματολόγια μας τόσο από δήμους και φορείς σχετικά με το σύστημα ύδρευσης και το πρόβλημα της μόλυνσης του Ασωπού, όσο και από κατοίκους των περιοχών. Εξετάζονται, τέλος, λύσεις για την αντιμετώπιση του προβλήματος και βγαίνουν συμπεράσματα χρήσιμα τόσο για την παρούσα κατάσταση όσο και για μελλοντικές ενέργειες.In the present project work, we are studying the pollution problem of Asopos river through time and we are analyzing the environmental and economic effects in the wide area of south Eboikos bay and ,also, the crucial effects of hexavalent chromium and ,generally, heavy metals and ions for the health of the citizens. Moreover, we are listing many old measurements and analysis from the pollutants of Asopos river and we are comparing them with our new data. Our measurements were executed with the photometric methods of UV-VIS and AAS. We are quoting a number of industries of the region and the reaction of the people for the continuous pollution. There are also answers from questionnaires, from the cities and the operators ,but also from the citizens, which examine the irrigation system and the problem of the pollution. Finally, we examine solutions to face this problem and we come to some conclusions that may be useful for the present and the future.Χριστόφορος-Γρηγόριος Ν. Σωφρονίο

Ready for life? The literacy achievements of Irish 15-year olds with comparative international data

Summary held at m01/41629SIGLEAvailable from British Library Document Supply Centre-DSC:m01/41629 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Ready for life? The literacy achievements of Irish 15-year-olds with comparative international data: summary report

Main report held at m01/41629SIGLEAvailable from British Library Document Supply Centre-DSC:m01/41630 / BLDSC - British Library Document Supply CentreGBUnited Kingdo