Selective recruitment designs for improving observational studies using electronic health records

Large‐scale electronic health records (EHRs) present an opportunity to quickly identify suitable individuals in order to directly invite them to participate in an observational study. EHRs can contain data from millions of individuals, raising the question of how to optimally select a cohort of size n from a larger pool of size N . In this article, we propose a simple selective recruitment protocol that selects a cohort in which covariates of interest tend to have a uniform distribution. We show that selectively recruited cohorts potentially offer greater statistical power and more accurate parameter estimates than randomly selected cohorts. Our protocol can be applied to studies with multiple categorical and continuous covariates. We apply our protocol to a numerically simulated prospective observational study using an EHR database of stable acute coronary disease patients from 82 089 individuals in the U.K. Selective recruitment designs require a smaller sample size, leading to more efficient and cost‐effective studies

Učinak eksplicitnog uključujućeg refleksivnog poučavanja na znanstvenu pismenost

The purpose of this study was to investigate the effectiveness of explicit-embedded-reflective (EER) instruction in scientific literacy levels of the ninth grade advanced science students by assessing content knowledge and scientific literacy levels. The study was conducted with 51 students by using experimental design. In the treatment group, the EER teaching was performed, while in the comparison group the instruction was conducted by lecturing, demonstration and questioning strategies in a teacher-centred context. Nature of Science Literacy Test and Cell Content Knowledge Test were used for data collection. T-tests were utilized for data analysis. The results of the study showed that the EER teaching was effective in terms of increase in scientific literacy levels and cell content knowledge in the treatment group. In addition, the approach was more effective in increasing scientific literacy levels and cell content knowledge than the regular approach.Svrha ovoga rada bila je istražiti učinkovitost eksplicitno-uključujuće-refleksivne metode poučavanja (dalje u tekstu EER) na znanstvenu pismenost naprednih učenika devetih razreda iz prirodoslovlja procjenjujući poznavanje sadržaja i razinu znanstvene pismenosti. U istraživanju je sudjelovao 51 učenik, a provedeno je uz pomoć eksperimentalnog nacrta. U eksperimentalnoj skupini primijenjeno je poučavanje metodom EER, a u kontrolnoj skupini poučavanje je provedeno u obliku predavanja, demonstracija i strategija ispitivanja u kontekstu koji je orijentiran na nastavnika. Za prikupljanje podataka korišteni su Test znanstvene pismenosti i Test o poznavanju stanice. Za analizu podataka korišteni su T-testovi. Rezultati ovoga istraživanja pokazali su da je primjena EER metode u poučavanju učinkovita s obzirom na povećanje razina znanstvene pismenosti i znanja o stanici u eksperimentalnoj skupini. Nadalje, taj je pristup bio učinkovitiji kod podizanja razine znanstvene pismenosti i znanja o stanici od uobičajene metode poučavanja

The data hungry home

It's said that the pleasure is in the giving, not the receiving. This belief is validated by how humans interact with their family, friends and society as well as their gardens, homes, and pets. Yet for ubiquitous devices, this dynamic is reversed with devices as the donors and owners as the recipients. This paper explores an alternative paradigm where these devices are elevated, becoming members of Data Hungry Homes, allowing us to build relationships with them using the principles that we apply to family, pets or houseplants. These devices are developed to fit into a new concept of the home, can symbiotically interact with us and possess needs and traits that yield unexpected positive or negative outcomes from interacting with them. Such relationships could enrich our lives through our endeavours to “feed” our Data Hungry Homes, possibly leading us to explore new avenues and interactions outside and inside the home

Replacement problem in Web caching

Caching has been recognized as an effective scheme for avoiding service bottleneck and reducing network traffic in World Wide Web. Our work focuses on the replacement problem in Web caching, which arises due to limited storage. We seek the best configuration for a fully connected network of N caches. The problem is formulated as a discrete optimization problem. A number of low complexity heuristics are studied to obtain approximate solutions. Performances are tested under fictitious probabilistic request sequences access logs of real Web traffic. LFD (longest-forward-distance), the classical optimal off-line paging algorithm, is observed not to be optimal. Instead a window scheme should be used. Under an unchanging request pattern, a simple static placement algorithm achieves the maximum hit rates using the arrival probabilities. Otherwise, for quick adaptation to changing requests and for better worst-case performances a randomized algorithm should be chosen. We also give an analysis of Web data to propose best heuristics for its characteristics. © 2003 IEEE