Sufficient jackknife-after-bootstrap method for detection of influential observations in linear regression models

In this study, we adapt sufficient bootstrap into the jackknife-after-bootstrap (JaB) algorithm. The performances of the sufficient and conventional JaB methods have been compared for detecting influential observations in linear regression. Comparison is based on two real-world examples and an extensive designed simulation study. Design includes different sample sizes and various modeling scenarios. The results reveal that proposed method is a good competitor for conventional JaB method with less standard error and amount of computation.     

Optimal regular graph designs

A typical problem in optimal design theory is finding an experimental design that is optimal with respect to some criteria in a class of designs. The most popular criteria include the A- and D-criteria. Regular graph designs occur in many optimality results, and if the number of blocks is large enough, an A-optimal (or D-optimal) design is among them (if any exist). To explore the landscape of designs with a large number of blocks, we introduce extensions of regular graph designs. These are constructed by adding the blocks of a balanced incomplete block design repeatedly to the original design. We present the results of an exact computer search for the best regular graph designs and the best extended regular graph designs with up to 20 treatments v, block size \(k \le 10\) and replication r \(\le 10\) and \(r(k-1)-(v-1)\lfloor r(k-1)/(v-1)\rfloor \le 9\).     

Robust multivariate diagnostics for PLSR and application on high dimensional spectrally overlapped drug systems

ABSTRACT

Statistical methods are effectively used in the evaluation of pharmaceutical formulations instead of laborious liquid chromatography. However, signal overlapping, nonlinearity, multicollinearity and presence of outliers deteriorate the performance of statistical methods. The Partial Least Squares Regression (PLSR) is a very popular method in the quantification of high dimensional spectrally overlapped drug formulations. The SIMPLS is the mostly used PLSR algorithm, but it is highly sensitive to outliers that also effect the diagnostics. In this paper, we propose new robust multivariate diagnostics to identify outliers, influential observations and points causing non-normality for a PLSR model. We study performances of the proposed diagnostics on two everyday use highly overlapping drug systems: Paracetamol–Caffeine and Doxylamine Succinate–Pyridoxine Hydrochloride.     

Statistical issues in the prospective monitoring of health outcomes across multiple units

Summary.  Following several recent inquiries in the UK into medical malpractice and failures to deliver appropriate standards of health care, there is pressure to introduce formal monitoring of performance outcomes routinely throughout the National Health Service. Statistical process control (SPC) charts have been widely used to monitor medical outcomes in a variety of contexts and have been specifically advocated for use in clinical governance. However, previous applications of SPC charts in medical monitoring have focused on surveillance of a single process over time. We consider some of the methodological and practical aspects that surround the routine surveillance of health outcomes and, in particular, we focus on two important methodological issues that arise when attempting to extend SPC charts to monitor outcomes at more than one unit simultaneously (where a unit could be, for example, a surgeon, general practitioner or hospital): the need to acknowledge the inevitable between-unit variation in 'acceptable' performance outcomes due to the net effect of many small unmeasured sources of variation (e.g. unmeasured case mix and data errors) and the problem of multiple testing over units as well as time. We address the former by using quasi-likelihood estimates of overdispersion, and the latter by using recently developed methods based on estimation of false discovery rates. We present an application of our approach to annual monitoring 'all-cause' mortality data between 1995 and 2000 from 169 National Health Service hospital trusts in England and Wales.     

East is West? National feelings and anti-immigrant sentiment in Europe

This article challenges the conventional dichotomy between the civic-Western and ethnic-Eastern forms of national attachments and empirically explores the link between national feelings and anti-immigrant sentiment, as expressed by European publics. We use data from the 1995 and 2003 ISSP modules to: (1) expose the multidimensional nature of national feelings, and (2) investigate the cross-country variation in mean levels and inter-regional heterogeneity in the severity of effects on anti-immigrant sentiment for four dimensions of national feelings. The results show that there are important regional differences in the mean levels and effects exerted by the civic and ethnic national feelings at both points in time. Overall, these findings point to the limited relevance of the conceptual demarcation between the Western-civic and Eastern-ethnic types, as a trend of cross-regional convergence is rather strongly supported. We discuss the implications of the results within the broader context of post-communist transition and eastward enlargement of the European Union.     

Pathophysiology of premenstrual syndrome and premenstrual dysphoric disorder

Premenstrual syndrome (PMS) and premenstrual dysphoric disorder are triggered by hormonal events ensuing after ovulation. The symptoms can begin in the early, mid or late luteal phase and are not associated with defined concentrations of any specific gonadal or non-gonadal hormone. Although evidence for a hormonal abnormality has not been established, the symptoms of the premenstrual disorders are related to the production of progesterone by the ovary. The two best-studied and relevant neurotransmitter systems implicated in the genesis of the symptoms are the GABArgic and the serotonergic systems. Metabolites of progesterone formed by the corpus luteum of the ovary and in the brain bind to a neurosteroid-binding site on the membrane of the gamma-aminobutyric acid (GABA) receptor, changing its configuration, rendering it resistant to further activation and finally decreasing central GABA-mediated inhibition. By a similar mechanism, the progestogens in some hormonal contraceptives are also thought to adversely affect the GABAergic system. The lowering of serotonin can give rise to PMS-like symptoms and serotonergic functioning seems to be deficient by some methods of estimating serotonergic activity in the brain; agents that augment serotonin are efficacious and are as effective even if administered only in the luteal phase. However, similar to the affective disorders, PMS is ultimately not likely to be related to the dysregulation of individual neurotransmitters. Brain imaging studies have begun to shed light on the complex brain circuitry underlying affect and behaviour and may help to explicate the intricate neurophysiological foundation of the syndrome.     

Relation of infants' and mothers' pointing to infants' vocabulary measured directly and with parental reports

Infants' and parents' pointing gestures predict infants' concurrent and prospective language development. Most studies have measured vocabulary size using parental reports. However, parents tend to underestimate or overestimate infants' vocabulary necessitating the use of direct measures alongside parent reports. The present study examined whether mothers' index-finger pointing, and infants' whole-hand and index-finger pointing at 14 months associate with infants' receptive and expressive vocabulary based on parental reports and directly measured lexical processing efficiency (LPE) concurrently at 14 months and prospectively at 18 months. We used the decorated room paradigm to measure pointing frequency, the Turkish communicative development inventory I to measure infants' receptive vocabulary, Turkish communicative development inventory II to measure their expressive vocabulary, and the Looking-While-Listening (LWL) task to measure LPE. At 14 months, 34 mother-infant dyads, and at 18 months, 30 dyads were included in the analyses. We found that only infants' index-finger pointing frequency at 14 months predicted their LPE (both reaction time and accuracy) prospectively at 18 months but not concurrently at 14 months. Neither maternal pointing nor infants' pointing predicted their receptive and expressive vocabulary based on indirect measurement. The results extend the evidence on the relation between index-finger pointing and language development to a more direct measure of vocabulary.     

An Assessment of EU 2020 Strategy: Too Far to Reach?

In 2010, EU adopted a new growth strategy which includes three growth priorities and five headline targets to be reached by 2020. The aim of this paper is to investigate the current performance of the EU member and candidate states in achieving these growth priorities and the overall strategy target by allocating the headline targets into the priorities and the priorities into the strategy by the use of a composite indicator methodology. The paper determines how far away each member and candidate state is from the targeted levels of the priorities and the strategy by making a distinction between EU 15 and relatively new member states as well. The developed composite indices enable the observation of the performances of the member and candidate states in a single indicator for the overall strategy and each growth priority. The results of the strategy index and three growth priority indices show that Nordic states possess the highest index scores already having reached many of the targets; many new member states performed as good as EU 15 and some EU 15 states are placed at the bottom of the ranking with quite poor performance in reaching the EU 2020 strategy.     

Should International Migration Be Encouraged to Offset Population Aging? A Cross-Country Analysis of Public Attitudes in Europe

Concerns about population aging in Europe have occupied the attention of policy makers and demographers for over a decade. Some policy makers have proposed increased immigration to offset the aging of the population (i.e., replacement migration). However, demographers have estimated that a very high (and likely untenable) level of immigration would be required, and little is known about whether the national publics of Europe would support international migration as a potential solution to population aging. Using Eurobarometer data from 2006 and concurrent country-level measures from Eurostat, this study examines individual- and contextual-level factors related to public attitudes toward immigration as an effective solution to the problem of population aging in the current 27 member countries of the European Union. Results from multilevel logit analyses indicate that urban, university-educated, and childless individuals are consistently more likely than others to endorse replacement migration. Countries with more prosperous economies and proportionally fewer foreign-born residents also show more supportive attitudes. Such results echo research on anti-immigrant sentiment, suggesting considerable public resistance to population policies that might encourage large-scale immigration. At the same time, these findings show consistent patterns of endorsement despite demographers’ criticism of the concept of replacement migration and concerns about developing alternative long-term strategies.     

Correlates of infant pointing frequency in the first year

This study examines the emergence of concurrent correlates of infant pointing frequency with the aim of contributing to its ontogenetic theories. We measured monthly from 8 to 12 months infants' (N = 56) index-finger pointing frequency along with several candidate correlates: (1) family socioeconomic status (SES), (2) mothers' pointing production, and (3) infants' point following to targets in front of and behind them. Results revealed that (1) infants increased their pointing frequency across age, but high-SES infants had a steeper increase, and a higher pointing frequency than low-SES infants from 10 months onward, (2) maternal pointing frequency was not associated with infant pointing frequency at any age, (3) infants' point following abilities to targets behind their visual fields was positively associated with their pointing frequency at 12 months, after pointing had already emerged around 10 months. Findings suggest that family SES impacts infants' pointing development more generally, not just through maternal pointing. The association between pointing and following points to targets behind, but not in front, suggests that a higher level of referential understanding emerges after, and perhaps through the production of pointing.