Edgeworth expansion for the sample autocorrelation function

Fractionally integrated process, introduced independently by Granger and Joyeux (1980) and Hosking (1981), exhibit second-order dependence structures of rich variety, and stir much interest by way of their mathematical properties and their applications in modelling real phenomena. Their mathematical complexity oers signicant challenges in deriving estimates of parameters relating to the long memory behaviour, both in parametric and non-parametric models, with the latter having slower convergence properties. Some seminal papers include those by Yajima (1985), Fox and Taqqu (1986), and Dahlhaus (1988, 1989) on parametric estimation, and by Hurst (1951), Geweke and Porter-Hudak (1983), Robinson (1995) and Hurvich et al. (1998). We have in mind to consider the ACF bootstrap (as it is called), based on a result of Ramsey (1974), which generates a surrogate series

Flipping the roles: Analysis of a university course where students become co-creators of curricula

In this paper I present the transformation of a university course inspired by the theoretical background of the student voice approach (Fielding, 2004a and 2004b; Cook-Sather, 2006) and, in particular, the ways students are encouraged to be \u201cco-creators of curricula\u201d through partnership with faculty (Bovill, Cook\u2010Sather & Felten, 2011). I introduce active learning practices centered on \u201cstudent generated content\u201d (Sener, 2007; Bates et al., 2012), allowing a new rendering of the traditional lesson cycle: frontal lesson, individual study, and final exam. The change in students\u2019 attitude towards study and final exam support the effectiveness of this methodology

Validità e affidabilità del peer-grading nella formazione di insegnanti in servizio

This paper aims to investigate the validity and reliability of peer-grading in in-service teacher training, a field where this practice has been little explored. The study has examined the peer-grading results in an inservice teacher training course involving high school teachers. The validity was measured by using the similarity between peer-grading and trainer-grading scorescalculated by the Pearson correlation coefficient; while the reliability was measured by using the agreement of scores given by multiple peer graders calculated by the intraclass correlation coefficient. The empirical findings indicate that in-training teachers provided scores similar to those of the course trainers as well as fairly consistent grading results, thus highlighting that peer-generated grades seems to be valid and reliable in the field of in-service teacher training.Il presente contributo indaga la validità e l’affidabilità del peer-grading nell’ambito della formazione di insegnanti in servizio, contesto in cui questa pratica è poco esplorata.Lo studio ha esaminato l’attività di peergrading svolta in un percorso di formazione che ha coinvolto insegnanti di scuola superiore. La validità è stata misurata analizzando la somiglianza tra i punteggi attribuiti dagli insegnanti e quelli dei docenti del corso utilizzando il coefficiente di correlazione di Pearson. L’affidabilità è stata misurata analizzando l’accordo tra i punteggi fornitidai diversi insegnanti utilizzando il coefficiente di correlazione intraclasse. I risultati indicano che gli insegnanti hanno fornito punteggi simili a quelli dei docenti del corso e punteggi abbastanza coerenti tra loro, evidenziando come il peer-grading sembri essere valido e affidabile nell’ambito della formazione degli insegnanti in servizio

Heritability estimates of enteric methane emissions predicted from fatty acid profiles, and their relationships with milk composition, cheese-yield and body size and condition

In the present study we estimated the genetic parameters of enteric methane emissions (EME) traits predicted from milk fatty acid profile (FA) and those of their predictors in 1,091 Brown Swiss cows reared on 85 farms in order to assess the potential of using EME-related phenotypes in selective breeding. Univariate and bivariate genetic models were fitted in a Bayesian framework. The means of the marginal posterior distribution of intra-herd heritability ranged from 0.12 for estimated methane production (g/d/cow) to 0.24 for estimated methane yield (g/kg dry matter intake [DMI]), with intermediate values for estimated methane intensity, increasingly higher when expressed per kg of corrected milk (0.13), fresh cheese (0.16), or cheese solids (0.20). Regarding the correlations, the milk quality traits and percentage cheese yields were generally moderately correlated with the estimated EME traits, and were variable in terms of sign. Daily milk and cheese yield traits were, as expected, all highly positively correlated with estimated daily methane production. In contrast, they were negatively correlated with estimated methane yield and intensity, the estimates being large in the case of phenotypic and herd correlations, and low in the case of additive genetic and residual correlations. With the exception of the negative correlations with daily methane production, EME traits exhibited trivial correlations with body size and BCS of cows, which, in turn, were negatively correlated with milk yield. Although the results should be validated on a larger population and different breeds, our study demonstrate the presence of additive genetic variation of EME traits, which could be exploited in breeding programmes for the improvement in both milk production and the ecological footprint of dairy farming.HighlightsEnteric methane emissions (EME) of dairy cows can be estimated on the basis of milk fatty acid profile.EME exhibited exploitable genetic variation.Genetic selection could be preferentially based on predicted methane intensity per kg of milk, or per kg of cheese in countries where milk production is used mainly for cheese-making. Enteric methane emissions (EME) of dairy cows can be estimated on the basis of milk fatty acid profile. EME exhibited exploitable genetic variation. Genetic selection could be preferentially based on predicted methane intensity per kg of milk, or per kg of cheese in countries where milk production is used mainly for cheese-making

Validity and reliability of peer-grading in in-service teacher training

This paper aims to investigate the validity and reliability of peer-grading in in-service teacher training, a field where this practice has been little explored. The study has examined the peer-grading results in an in-service teacher training course involving high school teachers. The validity was measured by using the similarity between peer-grading and trainer-grading scores calculated by the Pearson correlation coefficient; while the reliability was measured by using the agreement of scores given by multiple peer graders calculated by the intraclass correlation coefficient. The empirical findings indicate that in-training teachers provided scores similar to those of the course trainers as well as fairly consistent grading results, thus highlighting that peer-generated grades seems to be valid and reliable in the field of in-service teacher training

A new bootstrap approach for Gaussian long memory time series.

In this work we introduce a new bootstrap approach based on a result of Ramsey (1974) and on the Durbin-Levinson algorithm to obtain surrogate series from linear Gaussian processes with long range dependence. First we investigate properties of this type of bootstrap, then we apply the method to semi-parametric estimators of the long memory parameter. We find out that the performance of our bootstrap procedure is superior, in terms of MSE, to other established approaches