1,152 research outputs found
Quantum analysis of a nonlinear microwave cavity-embedded dc SQUID displacement detector
We carry out a quantum analysis of a dc SQUID mechanical displacement
detector, comprising a SQUID with mechanically compliant loop segment, which is
embedded in a microwave transmission line resonator. The SQUID is approximated
as a nonlinear, current dependent inductance, inducing an external flux
tunable, nonlinear Duffing self-interaction term in the microwave resonator
mode equation. Motion of the compliant SQUID loop segment is transduced
inductively through changes in the external flux threading SQUID loop, giving a
ponderomotive, radiation pressure type coupling between the microwave and
mechanical resonator modes. Expressions are derived for the detector signal
response and noise, and it is found that a soft-spring Duffing self-interaction
enables a closer approach to the displacement detection standard quantum limit,
as well as cooling closer to the ground state
Interactive effects of vascular risk burden and advanced age on cerebral blood flow.
Vascular risk factors and cerebral blood flow (CBF) reduction have been linked to increased risk of cognitive impairment and Alzheimer's disease (AD); however the possible moderating effects of age and vascular risk burden on CBF in late life remain understudied. We examined the relationships among elevated vascular risk burden, age, CBF, and cognition. Seventy-one non-demented older adults completed an arterial spin labeling MR scan, neuropsychological assessment, and medical history interview. Relationships among vascular risk burden, age, and CBF were examined in a priori regions of interest (ROIs) previously implicated in aging and AD. Interaction effects indicated that, among older adults with elevated vascular risk burden (i.e., multiple vascular risk factors), advancing age was significantly associated with reduced cortical CBF whereas there was no such relationship for those with low vascular risk burden (i.e., no or one vascular risk factor). This pattern was observed in cortical ROIs including medial temporal (hippocampus, parahippocampal gyrus, uncus), inferior parietal (supramarginal gyrus, inferior parietal lobule, angular gyrus), and frontal (anterior cingulate, middle frontal gyrus, medial frontal gyrus) cortices. Furthermore, among those with elevated vascular risk, reduced CBF was associated with poorer cognitive performance. Such findings suggest that older adults with elevated vascular risk burden may be particularly vulnerable to cognitive change as a function of CBF reductions. Findings support the use of CBF as a potential biomarker in preclinical AD and suggest that vascular risk burden and regionally-specific CBF changes may contribute to differential age-related cognitive declines
The Effect of Content Retelling on Vocabulary Uptake from a TED Talk
This study investigates the potential benefits for incidental vocabulary acquisition of implementing a particular sequence of input-output-input activities. More specifically, EFL learners (n = 32) were asked to watch a TED Talks video, orally sum up its content in English, and then watch the video once more. A comparison group (n = 32) also watched the TED Talks video twice but were not required to sum it up in between. Immediate and delayed post-tests showed significantly better word-meaning recall in the former condition. An analysis of the oral summaries showed that it was especially words which learners attempted to use that stood a good chance of being recalled later. These findings are interpreted with reference to Swainâs (e.g., 1995) Output Hypothesis, Laufer and Hulstijnâs (2001) Involvement Load Hypothesis, and Nation and Webbâs (2011) Technique Feature Analysis. What makes the text-based output task in this experiment fundamentally different from many previous studies which have investigated the merits of text-based output activities is that it was at no point stipulated for the participants that they should use particular words from the input text. The study also illustrates the potential of TED Talks as a source of authentic audio-visual input in EFL classrooms
Developmental changes associated with cross-language similarity in bilingual children
Online publication 30/9/2015The main goal of the present study was to investigate how the degree of orthographic
overlap between translation equivalents influences bilingual word recognition
processes at different stages of reading development. SpanishâBasque bilingual
children with ages ranging from 8 to 15 years were tested in an explicit translation
recognition task with a large set of items. Critically, the degree of cross-language
similarity (i.e. the cognate status) between the references and the correct targets was
manipulated along a continuum in order to investigate how the reliance on crosslanguage
orthographic overlap varies as a function of reading experience. Results
showed that younger children were significantly more sensitive to the cognate status
of words than older children while recognising translation equivalents, and that this
difference did not depend on the speed of response of the participants. These results
demonstrate that the influence of cross-language similarity progressively diminishes as
a function of increased exposure to print together with the maturation of the
mechanisms responsible for language interference suppression, as suggested by
developmental models of bilingual lexical access.This research has been partially funded by the Spanish Government [grant number PSI2012-32123], the European Research Council [grant number
ERC-AdG-295362], and by the AThEME project funded by the European Union [grant number 613465]
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Word frequency and trends in the development of French vocabulary in lower intermediate students during Year 12 in English schools
Chinese L2 learnersâ depth of vocabulary knowledge and its role in reading comprehension
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Using a Chinese Word Associates Test (WAT-C), this study examined the vocabulary depth of second language learners of Chinese and its contribution to the learnersâ reading comprehension. Results showed no significant effects of word frequency, word class (i.e., adjectives vs. verbs), and type of association relationships (i.e., paradigmatic vs. syntagmatic) on learnersâ WAT-C performance. More important, vocabulary depth was found to be a significant and unique predictor of reading comprehension over and above vocabulary size. On the other hand, the relative contributions of vocabulary depth and size depended on what types of texts were read and what comprehension skills were assessed. Specifically, for the long passage comprehension task with questions testing literal comprehension, vocabulary size was a more important predictor, whereas for the short passage comprehension task with questions testing inferencing, vocabulary depth was a more important predictor. These findings were discussed in light of the different levels of lexical complexity between the short and long passages and the different cognitive processing demands the questions of the two comprehension tasks placed on learners
An interactive mobile phone application, smart 5-a-day, for increasing knowledge of and adherence to fruit and vegetable recommendations: development and randomized controlled test
Background: Fruit and vegetable (FV) consumption is important for health, but many individuals fail 22 to consume adequate FV for health benefits. While many individuals are aware of current FV 23 consumption recommendations, research suggests that adherence to these recommendations is 24 hampered by low knowledge of the details of these recommendations. 25 Purpose: This paper reports the development and details of a pilot randomized controlled test of a 26 novel interactive mobile phone application (app) for addressing low knowledge of the UK 5 a day FV 27 recommendations. 28 Methods: Requirements for the app were first defined by researchers and potential end users, and 29 prioritised using the MoSCoW method. A prototype smart phone app was then developed using an 30 agile approach. Third, the prototype app was tested in a randomized controlled pilot trial, for 31 impacts on FV knowledge and FV intakes. Volunteers were randomized to either receive (N=50) or 32 not receive the app (N=44) for two or four weeks, and FV knowledge, FV intakes, and FV behaviour 33 were assessed at study start and after 1, 2, and/or 4 weeks. App usage and qualitative feedback 34 were also investigated. All findings then informed the development of a final app. 35 Results: Low knowledge of the FV recommendations centred around portion sizes and the need for 36 variety, and an interactive mobile phone app was considered a suitable tool for improving this 37 knowledge in a practical manner, that would be available both at time of consumption and outside 38 of these times. The pilot test revealed improved FV behaviour after two weeks compared to baseline 39 in volunteers who received the app, but improvements in FV knowledge were found in both groups, 40 and no improvements in FV intake were found in formal measures. Patterns of app usage and 41 qualitative feedback also suggested a number of modifications. The resultant final app incorporates 42 several behaviour change techniques (goal-setting, self-monitoring, personalised feedback), as well 43 as aiming to improve knowledge. 44 Conclusions: A novel interactive mobile phone app was successfully developed based on 45 requirements, and when tested in a pilot randomized controlled trial, this app was found to have 46 some impacts on FV outcomes. While benefits from the app were small, impacts will likely increase 47 as a result of recent modifications. The final SMART 5-A-DAY app is available in the Google Play Store 48 and now needs testing in the target population
The QICKD study protocol: a cluster randomised trial to compare quality improvement interventions to lower systolic BP in chronic kidney disease (CKD) in primary care.
BACKGROUND: Chronic kidney disease (CKD) is a relatively newly recognised but common long-term condition affecting 5 to 10% of the population. Effective management of CKD, with emphasis on strict blood pressure (BP) control, reduces cardiovascular risk and slows the progression of CKD. There is currently an unprecedented rise in referral to specialist renal services, which are often located in tertiary centres, inconvenient for patients, and wasteful of resources. National and international CKD guidelines include quality targets for primary care. However, there have been no rigorous evaluations of strategies to implement these guidelines. This study aims to test whether quality improvement interventions improve primary care management of elevated BP in CKD, reduce cardiovascular risk, and slow renal disease progression DESIGN: Cluster randomised controlled trial (CRT) METHODS: This three-armed CRT compares two well-established quality improvement interventions with usual practice. The two interventions comprise: provision of clinical practice guidelines with prompts and audit-based education. The study population will be all individuals with CKD from general practices in eight localities across England. Randomisation will take place at the level of the general practices. The intended sample (three arms of 25 practices) powers the study to detect a 3 mmHg difference in systolic BP between the different quality improvement interventions. An additional 10 practices per arm will receive a questionnaire to measure any change in confidence in managing CKD. Follow up will take place over two years. Outcomes will be measured using anonymised routinely collected data extracted from practice computer systems. Our primary outcome measure will be reduction of systolic BP in people with CKD and hypertension at two years. Secondary outcomes will include biomedical outcomes and markers of quality, including practitioner confidence in managing CKD. A small group of practices (n = 4) will take part in an in-depth process evaluation. We will use time series data to examine the natural history of CKD in the community. Finally, we will conduct an economic evaluation based on a comparison of the cost effectiveness of each intervention. CLINICAL TRIALS REGISTRATION: ISRCTN56023731. ClinicalTrials.gov identifier
On the Reference Structure for the Resonance Energy of Aromatic Hydrocarbons
To use the Zagreb Group and Aihara definition of resonance
energy, it is necessary that the roots of the reference polynomial
all be real. A partial proof that they are has been obtained in three
ways. Direct solution of the reference polynomial for annulenes
shows all roots real in this case. Application of Sturm sequences
promises the complete proof in principle, but requires the proof of
inequalities which we have so far resolved only for molecules with
four or fewer atoms. A graph theoretical approach succeeds for all
conjugated hydrocarbons in which no edge is shared by two rings.
It is also suggested that the reference polynomial may be used for
discriminating planar isospectral molecules
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