The dynamics of multiword sequence extraction.

Being able to process multiword sequences is central for both language comprehension and production. Numerous studies support this claim, but less is known about the way multiword sequences are acquired, and more specifically how associations between their constituents are established over time. Here we adapted the Hebb naming task into a Hebb lexical decision task to study the dynamics of multiword sequence extraction. Participants had to read letter strings presented on a computer screen and were required to classify them as words or pseudowords. Unknown to the participants, a triplet of words or pseudowords systematically appeared in the same order and random words or pseudowords were inserted between two repetitions of the triplet. We found that response times (RTs) for the unpredictable first position in the triplet decreased over repetitions (i.e., indicating the presence of a repetition effect) but more slowly and with a different dynamic compared with items appearing at the predictable second and third positions in the repeated triplet (i.e., showing a slightly different predictability effect). Implicit and explicit learning also varied as a function of the nature of the triplet (i.e., unrelated words, pseudowords, semantically related words, or idioms). Overall, these results provide new empirical evidence about the dynamics of multiword sequence extraction, and more generally about the role of statistical learning in language acquisition.

On the role of interference in sequence learning in Guinea baboons (Papio papio).

It is well established that decay and interference are the two main causes of forgetting. In the present study, we specifically focus on the impact of interference on memory forgetting. To do so, we tested Guinea baboons (Papio papio) on a visuo-motor adaptation of the Serial Reaction Time task in which a target sequence is repeated, and a random sequence is interposed between repetitions, a similar situation as the one used in the Hebb repetition paradigm. In this task, one three-item sequence, the repeated sequence, was presented every second trial and interleaved with random sequences. Interference was implemented by using random sequences containing one item that was also part of the repeated sequence. In a first condition, the overlapping item was located at the same position as the repeated sequence. In a second condition, the overlapping item was located at one of the two other positions. In a third condition, there was no overlap between repeated and random sequences. Contrary to previous findings, our results reveal similar learning slopes across all three conditions, suggesting that interference did not affect sequence learning in the conditions tested. Findings are discussed in the light of previous research on sequence learning and current models of memory and statistical learning.

Sequential versus simultaneous presentation of memoranda in verbal working memory: (How) does it matter?

To-be-memorized information in verbal working memory (WM) can be presented sequentially, like in oral language, and simultaneously, like in written language. Few studies have addressed the importance and implications for verbal WM processing of these two presentation modes. While sequential presentation may favor discrete, temporal encoding processes, simultaneous presentation may favor spatial encoding processes. We compared immediate serial recall tasks for sequential versus simultaneous word list presentation with a specific focus on serial position curves of recall performance, transposition gradients, and the nature of serial order errors. First, we observed higher recall performance in the simultaneous compared to the sequential conditions, with a particularly large effect at end-of-list items. Moreover, results showed more transposition errors between non-adjacent items for the sequential condition, as well as more omission errors especially for start-of-list items. This observation can be explained in terms of differences in refreshing opportunities for start-of-list items during encoding between conditions. This study shows that the presentation mode of sequential material can have a significant impact on verbal WM performance, with an advantage for simultaneous encoding of sequence information.

Do serial order short-term memory and long-term learning abilities predict spelling skills in school-age children?

Compared to most human language abilities, the cognitive mechanisms underlying spelling have not been as intensively investigated as reading and therefore remain to this day less well understood. The current study aims to address this shortcoming by investigating the contribution of serial order short-term memory (STM) and long-term learning (LTL) abilities to emerging spelling skills. Indeed, although there are several reasons to assume associations between serial order memory and spelling abilities, this relationship has hardly been investigated empirically. In this study, we hypothesized that serial order STM plays an important role in spelling novel words, for which children are supposed to rely on a sequential nonlexical spelling procedure. Serial order LTL was hypothesized to be involved in the creation of more stable orthographic representations allowing children to spell (regular and irregular) words by using a lexical spelling strategy based on the direct access to orthographic representations stored in long-term memory. To assess these hypotheses, we conducted a longitudinal study in which we tested a sample of 116 French-speaking children at first grade and two years later at third grade of primary school. At first grade, we administered tasks that were specifically designed to maximize STM and LTL abilities for serial order information. At third grade, we assessed spelling abilities using irregular word, regular word, and pseudoword writing-to-dictation tasks. Bayesian regression analyses showed that pseudoword, but also irregular word spelling was best predicted by serial order STM, while regular word spelling was similarly predicted by both serial order STM and LTL.

The contribution of serial order short-term memory and long-term learning to reading acquisition: A longitudinal study.

There is increasing evidence for an association between both serial order short-term memory (STM) and the long-term learning (LTL) of serial order information and reading abilities. In this developmental study, we examined the hypothesis that STM for serial order supports online grapheme-to-phoneme conversion processes during the initial stages of reading acquisition, whereas the LTL of serial order serves reading abilities at later stages, when reading starts to rely on more stable, long-term orthographic representations. We followed a sample of 116 French-speaking children from first (Time 1 [T1]) grade of primary school through second (Time 2 [T2]) and third (Time 3 [T3]) grade. Their serial order STM and LTL abilities as well as their reading abilities were assessed. Overall, we observed that early reading abilities were only predicted by serial order STM performance, while more advanced reading abilities were predicted by both serial order STM and LTL performance. These results point toward a predictive role of serial order memory performance in reading acquisition and suggest that serial order STM and LTL support reading at different stages of acquisition. We further discuss our findings in the light of advancing knowledge about the relationship between memory and reading. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The developmental neural substrates of Hebb repetition learning and their link with reading ability.

Hebb repetition learning is a fundamental learning mechanism for sequential knowledge, such as language. However, still little is known about its development. This fMRI study examined the developmental neural substrates of Hebb repetition learning and its relation with reading abilities in a group of 49 children aged from 6 to 12 years. In the scanner, the children carried out an immediate serial recall task for syllable sequences of which some sequences were repeated several times over the course of the session (Hebb repetition sequences). The rate of Hebb repetition learning was associated with modulation of activity in the medial temporal lobe. Importantly, for the age range studied here, learning-related medial temporal lobe modulation was independent of the age of the children. Furthermore, we observed an association between regular and irregular word reading abilities and the neural substrates of Hebb repetition learning. This study suggests that the functional neural substrates of Hebb repetition learning do not undergo further maturational changes in school age children, possibly because they are sustained by implicit sequential learning mechanisms which are considered to be fully developed by that age. Importantly, the neural substrates of Hebb learning remain significant determinants of children's learning abilities, such as reading.

The developmental neural substrates of item and serial order components of verbal working memory.

Behavioral and developmental studies have made a critical distinction between item and serial order processing components of verbal working memory (WM). This functional magnetic resonance imaging (fMRI) study determined the extent to which item and serial order WM components are characterized by specialized neural networks already in young children or whether this specialization emerges at a later developmental stage. Total of 59 children aged 7-12 years performed item and serial order short-term probe recognition tasks in an fMRI experiment. While a left frontoparietal network was recruited in both item and serial order WM conditions, the right intraparietal sulcus was selectively involved in the serial order WM condition. This neural segregation was modulated by age, with both networks becoming increasingly separated in older children. Our results indicate a progressive specialization of networks involved in item and order WM processes during cognitive development.

Paper microfluidics for nucleic acid amplification testing (NAAT) of infectious diseases.

The diagnosis of infectious diseases is entering a new and interesting phase. Technologies based on paper microfluidics, coupled to developments in isothermal amplification of Nucleic Acids (NAs) raise opportunities for bringing the methods of molecular biology in the field, in a low setting environment. A lot of work has been performed in the domain over the last few years and the landscape of contributions is rich and diverse. Most often, the level of sample preparation differs, along with the sample nature, the amplification and detection methods, and the design of the device, among other features. In this review, we attempt to offer a structured description of the state of the art. The domain is not mature and there exist bottlenecks that hamper the realization of Nucleic Acid Amplification Tests (NAATs) complying with the constraints of the field in low and middle income countries. In this domain however, the pace of progress is impressively fast. This review is written for a broad Lab on a Chip audience.

Paper-based RNA detection and multiplexed analysis for Ebola virus diagnostics.

The most performing techniques enabling early diagnosis of infectious diseases rely on nucleic acid detection. Today, because of their high technicality and cost, nucleic acid amplification tests (NAAT) are of benefit only to a small fraction of developing countries population. By reducing costs, simplifying procedures and enabling multiplexing, paper microfluidics has the potential to considerably facilitate their accessibility. However, most of the studies performed in this area have not quit the lab. This letter brings NAAT on paper closer to the field, by using clinical samples and operating in a resource-limited setting. We first performed isothermal reverse transcription and Recombinase Polymerase Amplification (RT-RPA) of synthetic Ribonucleic Acid (RNA) of Ebola virus using paper microfluidics devices. We further applied this method in Guinea to detect the presence of Ebola virus in human sample RNA extracts, with minimal facilities (carry-on detection device and freeze-dried reagents on paper). RT-RPA results were available in few minutes and demonstrate a sensitivity of 90.0% compared to the gold-standard RT-PCR on a set of 43 patient samples. Furthermore, the realization of a nine-spot multilayered device achieving the parallel detection of three distinct RNA sequences opens a route toward the detection of multiple viral strains or pathogens.

Microfluidic technique for measuring wax appearance temperature of reservoir fluids.

A microfluidic technique for measuring wax appearance temperature (WAT) of reservoir fluids is presented. The technique is based on continuous monitoring of pressure across a microchannel as wax particles are deposited and gradually clog the channel. A rapid pressure increase was observed as the temperature was systematically decreased to wax appearance temperature. The relationship between pressure change rate and sample temperature is explored as the working principle in the proposed WAT measurement technique. This technique yields results which are comparable to measurements obtained from a cross-polar microscopy technique (CPM); the current industry-standard for WAT measurement. The method is validated by systematically investigating phase transition of pure hydrocarbons, binary mixtures, and real crude oils. The new technique has two distinct advantages over the existing industry standard methods in that its experimental setup is much simpler and it can be adapted to field applications. The microchannel can be easily cleaned and reused to test different samples.

[Did household parental smoking attitude change over the last 15 years? A survey among primary school children in the city of Agrigento, Italy]. / È cambiato qualcosa nelle abitudini dei genitori fumatori in ambito domestico negli ultimi 15 anni? Indagine epidemiologica tra gli alunni della città di Agrigento.

BACKGROUND: Exposure of children to passive tobacco smoking in the household setting has been demonstrated to cause respiratory diseases. Early atherosclerosis has also been demonstrated in young people previously exposed to passive tobacco smoking. Functional damage can initiate at the fetal age due to maternal smoking, with a tendency towards over-time progress. To date only scant data are available about indoor parental smoking attitudes and their changes after campaigns against smoke and risk factors in exposed youths. Questionnaires are useful tools in order to search for information on cigarette smoking and parental household lifestyle. In this study, we asked pupils of primary schools for providing information on their relatives' every 5 years throughout the period 1994-2009. METHODS: A multiple-choice answer questionnaire about sharing household parental smoking was administered to all primary school children (mean age 10.5 ± 0.5 years) of the city of Agrigento (Sicily, Italy). RESULTS: A total of 2221 questionnaires were collected from 637 children in 1994, 687 in 1999, 516 in 2004, and 381 in 2009. Important findings show a significant reduction in both smoking parents and exposure to passive tobacco smoking (from 64% in 1994 to 45% in 2009, p<0.00001). In 2009, 22% of mothers and 39% of fathers resulted to be smokers in the household setting yet. CONCLUSIONS: In agreement with the 2011 Italian DOXA survey on the general population, the present study demonstrates a negative trend in the prevalence of household smoker parents (predominantly mothers) and exposure of children to passive tobacco smoking. These results likely reflect such a greater awareness about smoke-related risks in children, and the effectiveness of medical campaigns against cardiovascular risk factors as well.