Examining the Relation Among Subjective Age and Working Memory in Old Age on a High-Frequency Basis Across 7 Days

While increasing longitudinal evidence suggests that negative age views accelerate cognitive decline and increase dementia risk, we know little about such co-variance dynamics on a daily basis. We make use of subjective age and working memory performance data obtained six times a day over seven consecutive days as people went about their daily routines from 123 young-old (aged 66-69 years, 47.2% women) and 42 old-old (aged 86-90 years, 55.8% women) adults. Notably, multilevel models revealed considerably-sized short-term intra-individual variation of subjective age and working memory within days and these short-term within-day fluctuations in subjective age and working memory were coupled as expected. Hence, increased subjective age went along with lowered working memory confirming previous research. However, the respective between-day associations appeared reversed. Given this evidence of correlated short-term variability, we also discuss implications of different change dynamics that might explain moment-to-moment versus day-to-day associations between subjective age and working memory.

Woordenschatgraven

Summary Many vocabulary lists in Dutch coursebooks are indirectly based on frequency research, and on the assumption that any particular selection of Latin literature might benefit from a representative list. However, the selection of merely 50 pages of Latin for Dutch senior high school education exams does not hold up to both linguistic and statistical logic. As a practical work-around a dichotomy is suggested between ‘content words’ and ‘structure words’. Whereas the latter (conjunctions, prepositions, pronouns and adverbs with a general meaning) can acceptably be selected on a frequency basis, the selection of the former (nouns, adjectives and verbs) can be tailored to the specific content of a text corpus with the help of the ‘Collatinus’ open source application. Statistical samples are taken from eight recent final examination programs and the criteria for a tailormade selection are illustrated with Cicero’s Pro Roscio (national exams 2021). Various classroom activities and consequences for editing educational resources are presented.

A Bound on Expected Stock Returns

We present a sufficient condition under which the prices of options written on a particular stock can be aggregated to calculate a lower bound on the expected returns of that stock. The sufficient condition imposes a restriction on a combination of the stock’s systematic and idiosyncratic risk. The lower bound is forward-looking and can be calculated on a high-frequency basis. We estimate the bound empirically and study its cross-sectional properties. We find that the bound increases with beta and book-to-market ratio and decreases with size and momentum. The bound provides an economically meaningful signal about future stock returns. (JEL G11, G12) Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

214 Using Interictal Multivariate Granger Causality to Detect Epileptogenic Hubs

INTRODUCTION Surgical localization of epileptogenic networks requires significant intensive-care stays and facilitation of seizures for visual inspection. Multivariate Granger Causality (MVGC) provides a method of calculating the directional influence from each node to every other node during interictal data before seizures are facilitated after implantation of electrodes. MVGC is an efficient method of detecting biological coupling and has been shown to be robust against noise. Nodes identified as influential by MVGC have recently been shown to correlate with predicted seizure zones. METHODS Electrocorticography was examined and analyzed for five patients undergoing seizure localization surgery. Used ECOG channels were sampled at greater than 1.5 KHz for all patients. Model estimation was performed, and MVGC was used to calculate patterns of directional coupling over 100 second time windows. MVGC was performed on entire stays for two patients and on subsampled data for 3 patients. Coupling was also examined in the frequency domain to establish frequency basis of information exchange. Comparisons were made after blinded analysis was complete with seizure nodes identified by epileptologists. RESULTS >Five patients were included with more than 12 weeks of recorded data. MVGC adjacency matrices from interictal data over time from each patient revealed significant dominance by few nodes (average 1.8). Coupling changed little over time with highly accurate reconstructions after an average of 184 minutes when compared to the average matrix over the entire stay. On comparison to seizure onset nodes determined by epileptologist, the analysis found concordance 92.1% of the time with high significance compared to randomly selected channels (P < 0.00001). CONCLUSION MVGC is a method of detecting directional coupling in ECOG recordings. Previous and current work suggests that influential nodes during interictal data may predict epileptogenic hubs. Data collection may only require a few hours to reproduce the predicted influential nodes, potentially dramatically reducing the required length of stay.

Localization Operators and an Uncertainty Principle for the Discrete Short Time Fourier Transform

Localization operators in the discrete setting are used to obtain information on a signalffrom the knowledge on the support of its short time Fourier transform. In particular, the extremal functions of the uncertainty principle for the discrete short time Fourier transform are characterized and their connection with functions that generate a time-frequency basis is studied.

Effects of dietary fibre and feeding frequency on wool biting and aggressive behaviours in housed Merino sheep

Wool biting is a behaviour that can develop in housed sheep, in which sheep start to bite and eat the wool of others. The aim of this study was to determine whether (i) supplementing the diet of housed sheep with fibre and (ii) increasing feeding frequency would help to reduce wool biting, aggressive behaviours and wool damage. In a 2 × 2 factorial experiment, 40 Merino wethers were either fed with lucerne-based pellets only, or with pellets supplemented with barley straw. They received their pellets either on a low feeding frequency basis (once a day Monday to Friday mornings, double ration on Friday afternoon, nothing Saturdays and Sundays), or on a high feeding frequency basis (twice a day, every day). The sheep were housed in 4 treatment pens, each with 10 animals. Wool biting and aggressive behaviours were recorded through direct observation and the sheep were scored for wool damage twice a week during the 15-week study. The provision of fibre had a significant effect on reducing wool biting (P<0.001) and wool damage score (P<0.001). There was no consistent effect of feeding frequency on wool biting or wool damage, and no fibre × feeding frequency interactions. Whereas wool biting in general increased with time during the study (P<0.001), levels of aggressive behaviour showed no consistent time trend, and there were no effects of fibre or feeding frequency treatments. It is concluded that wool biting is largely a redirected behaviour in concentrate-fed housed sheep deprived of adequate levels of activity or oral stimulus, and that the provision of roughage will reduce the development of wool biting and improve animal welfare in housed experimental sheep.