438 research outputs found
High or low? Comparing high and low-variability phonetic training in adult and child second language learners
Background
High talker variability (i.e., multiple voices in the input) has been found effective in training nonnative phonetic contrasts in adults. A small number of studies suggest that children also benefit from high-variability phonetic training with some evidence that they show greater learning (more plasticity) than adults given matched input, although results are mixed. However, no study has directly compared the effectiveness of high versus low talker variability in children.
Methods
Native Greek-speaking eight-year-olds (N = 52), and adults (N = 41) were exposed to the English /i/-/ɪ/ contrast in 10 training sessions through a computerized word-learning game. Pre- and post-training tests examined discrimination of the contrast as well as lexical learning. Participants were randomly assigned to high (four talkers) or low (one talker) variability training conditions.
Results
Both age groups improved during training, and both improved more while trained with a single talker. Results of a three-interval oddity discrimination test did not show the predicted benefit of high-variability training in either age group. Instead, children showed an effect in the reverse direction—i.e., reliably greater improvements in discrimination following single talker training, even for untrained generalization items, although the result is qualified by (accidental) differences between participant groups at pre-test. Adults showed a numeric advantage for high-variability but were inconsistent with respect to voice and word novelty. In addition, no effect of variability was found for lexical learning. There was no evidence of greater plasticity for phonetic learning in child learners.
Discussion
This paper adds to the handful of studies demonstrating that, like adults, child learners can improve their discrimination of a phonetic contrast via computerized training. There was no evidence of a benefit of training with multiple talkers, either for discrimination or word learning. The results also do not support the findings of greater plasticity in child learners found in a previous paper (Giannakopoulou, Uther & Ylinen, 2013a). We discuss these results in terms of various differences between training and test tasks used in the current work compared with previous literature
Verifying the Safety of a Flight-Critical System
This paper describes our work on demonstrating verification technologies on a
flight-critical system of realistic functionality, size, and complexity. Our
work targeted a commercial aircraft control system named Transport Class Model
(TCM), and involved several stages: formalizing and disambiguating requirements
in collaboration with do- main experts; processing models for their use by
formal verification tools; applying compositional techniques at the
architectural and component level to scale verification. Performed in the
context of a major NASA milestone, this study of formal verification in
practice is one of the most challenging that our group has performed, and it
took several person months to complete it. This paper describes the methodology
that we followed and the lessons that we learned.Comment: 17 pages, 5 figure
Method of Controlling Corona Effects and Breakdown Voltage of Small Air Gaps Stressed by Impulse Voltages
This paper investigates the influence of a resistor on the dielectric
behavior of an air gap. The resistor is connected in series with the air gap
and the latter is stressed by impulse voltage. Air gap arrangements of
different geometry with either the rod or the plate grounded are stressed with
impulse voltages of both positive and negative polarity. The resistor is
connected in series with the air gap in the return circuit connecting the gap
with the impulse generator. The method followed involves the investigation of
the graphs of the charging time concerning the air gaps capacitances, in
connection to the value of the resistor, the geometry of the gap, the effect of
grounding and the polarity effect. It is determined that the charging time of
the air gap increases, as the value of the resistor increases. It is also
determined that the peak voltage value of the fully charged air gap decreases
as the value of the resistor increases. The results of the mathematical and
simulation analysis are compared with the results of the oscillograms taken
from experimental work. In addition and consequently to the above results it is
concluded from the experimental work that the in series connection of the
resistor in the circuit has significant influence on corona pulses (partial
discharges) occurring in the gap and on the breakdown voltage of the gap. A new
method of controlling the corona effects and consequently the breakdown voltage
of small air gaps stressed by impulse voltage of short duration in connection
to the ground effect and the polarity effect has arisen. Furthermore through
mathematical analysis of the charging graphs obtained from simulation and
experimental oscillograms there was a calculation of the values of the
capacitance of the air gaps in relation to their geometry and the results were
compared to the values calculated with mathematical analysis.Comment: 8 pages, 14 figure
Use of Online Dietary Recalls among Older UK Adults:A Feasibility Study of an Online Dietary Assessment Tool
This study examined the feasibility of including myfood24, an online 24-hour dietary recall tool, in a cohort studies of older adults. Participants (n = 319) were recruited during follow-up visits for the CHARIOT-Pro Sub-study, a prospective study of cognitively healthy adults aged 60–85 years at baseline. Email invitations were sent over three consecutive months, with weekly reminders. Multivariable regression models were applied to examine the number of recalls completed in relation to technology readiness (TR) scores and demographic characteristics. Ninety-four percent of people agreed to participate. Among participants, 67% completed at least one recall, and 48% completed two or more. Participants who completed multiple recalls reported higher self-confidence with technology and received a higher TR score than those who did not complete any recalls. A one-point higher TR score was associated with higher odds of completing three recalls compared to zero recalls (OR 1.70, 95% CI 0.96–3.01); this association was further attenuated after adjustment for demographic and other TR-related covariates (OR 1.35, 95% CI 0.63–2.88). This study demonstrates reasonable participation rates for a single myfood24 recall among older adults participating in a cohort study but suggests that further support may be required to obtain multiple recalls in this population
Parallel and serial mediation analysis between pain, anxiety, depression, fatigue and nausea, vomiting and retching within a randomised controlled trial in patients with breast and prostate cancer
Objective Cancer treatment is a particularly stressful period for the
patient. The reasons vary and include fear of treatment outcome as well
as treatment induced side effects. The patient frequently experiences
simultaneously various side effects resulting in a diminishing of the
patient's health-related quality of life (HRQoL). The study provides
evidence on the co-occurrence and inter-relations between pain, anxiety,
depression and fatigue in patients with breast and prostate cancer.
Design This paper presents a secondary analysis of the data from a
randomised control trial designed to test the effectiveness of guided
imagery and progressive muscle relaxation on pain, fatigue, anxiety and
depression. Non-parametric bootstrapping analyses were used to test the
mediational model of anxiety, fatigue and depression as parallel
mediators of the relationship between pain and HRQoL. Setting The study
was undertaken at the home setting. Participants In total 208 patients
were included in the study (assigned equally in two groups), referred at
the outpatient clinics of the three participating cancer care centres.
Results The three mediators fully mediate the relationship between pain
and HRQoL indirect effect (IE overall =-0.3839, 95% CI: Lower limit
(LL)=-0.5073 to upper limit (UL)=-0.2825) indicating that patients with
increased pain are likely to have higher levels of anxiety, fatigue and
depression. Gender significantly moderated the mediational effect of
Fatigue Index of Moderated Mediation (IMM=-0.2867 SE=0.1526, LL=-0.6127,
UL=-0.0226) but did not moderate mediational effect of anxiety
(IMM=-0.0709, SE=0.1414, LL=-0.3459, UL=+0.2089). The results show that
the three mediators in a serial causal order fully mediate the
relationship between pain and HRQoL (IE overall =-0.384, 95% CI:
LL=-0.51 to UL=-0.284) and the ratio of the overall indirect effect to
the total effect is 0.8315 (95% CI: LL=0.5683 to UL=1.1718). Conclusion
This work provides evidence that targeting fatigue, anxiety and
depression may have a meaningful effect on pain as a related symptom and
potentially have a positive impact on HRQoL of patients with breast and
prostate cancer.</p
Adolescent Verbal Memory as a Psychosis Endophenotype: A Genome-Wide Association Study in an Ancestrally Diverse Sample
Verbal memory impairment is one of the most prominent cognitive deficits in psychosis. However, few studies have investigated the genetic basis of verbal memory in a neurodevelopmental context, and most genome-wide association studies (GWASs) have been conducted in European-ancestry populations. We conducted a GWAS on verbal memory in a maximum of 11,017 participants aged 8.9 to 11.1 years in the Adolescent Brain Cognitive Development Study®, recruited from a diverse population in the United States. Verbal memory was assessed by the Rey Auditory Verbal Learning Test, which included three measures of verbal memory: immediate recall, short-delay recall, and long-delay recall. We adopted a mixed-model approach to perform a joint GWAS of all participants, adjusting for ancestral background and familial relatedness. The inclusion of participants from all ancestries increased the power of the GWAS. Two novel genome-wide significant associations were found for short-delay and long-delay recall verbal memory. In particular, one locus (rs9896243) associated with long-delay recall was mapped to the NSF (N-Ethylmaleimide Sensitive Factor, Vesicle Fusing ATPase) gene, indicating the role of membrane fusion in adolescent verbal memory. Based on the GWAS in the European subset, we estimated the SNP-heritability to be 15% to 29% for the three verbal memory traits. We found that verbal memory was genetically correlated with schizophrenia, providing further evidence supporting verbal memory as an endophenotype for psychosis
The impacts of social restrictions during the COVID-19 pandemic on the physical activity levels of over 50-year olds: the CHARIOT COVID-19 Rapid Response (CCRR) cohort study
Objectives To quantify the associations between shielding status and loneliness at the start of the COVID-19 pandemic, and physical activity (PA) levels throughout the pandemic. Methods Demographic, health and lifestyle characteristics of 7748 cognitively healthy adults aged >50, and living in London, were surveyed from April 2020 to March 2021. The International Physical Activity Questionnaire (IPAQ) short-form assessed PA before COVID-19 restrictions, and up to 6 times over 11 months. Linear mixed models investigated associations between baseline shielding status, loneliness, and time-varying PA. Results Participants who felt ‘often lonely’ at the outset of the pandemic completed an average of 522 and 547 fewer Metabolic Equivalent of Task (MET) minutes/week (95% CI: -809, -236, pConclusions Those shielding or lonely at pandemic onset were likely to have completed low levels of PA during the pandemic. These associations are influenced by co-morbidities and health status
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