1,276 research outputs found

    Metal-Rich SX Phe Stars in theKeplerField

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    High-resolution spectroscopic observations have been made for 32 of the 34 candidate SX Phe stars identiļ¬ed in the Kepler ļ¬eld by Balona & Nemec (2012). All available long- and short-cadence Q0-Q17 Kepler photometry has been analyzed for the 34 candidates. Radial velocities (RVs), space motions (U, V, W), projected rotation veloc- ities (v sin i), spectral types, and atmospheric characteristics (Teļ¬€ , log g, [M/H], vmic, etc.) were derived from āˆ¼160 spectra taken with the ESPaDOnS spectrograph on the Canada- France-Hawaii 3.6-m telescope and with the ARCES spectrograph on the Apache Point Observatory 3.5-m telescope. Two thirds of the stars are fast rotators with v sin i > 50 km/s, including four stars with v sin i > 200 km/s. Three of the stars have (negative) RVs > 250 km/s and retrograde space motions, and seven stars have total space motions > 400 km/s. All the spectroscopically measured SX Phe candidates have positions in a Toomre diagram that are consistent with being bona ļ¬de halo and thick-disk stars. Although several stars show a marked metal weakness, the mean [Fe/H] of the sample is near 0.0 dex (Ļƒ āˆ¼ 0.25 dex), which is considerably more metal-rich than is normally expected for a sample of Pop. II stars. Observed pulsation frequency modulations and optical time delays suggest that at least eight of the SX Phe stars are in binary systems, some of which show signif- icant RV variations. Six of the time-delay binaries have secondary masses ranging from 0.05 to 0.70 Mo and orbital periods in the range 9 to 1570 days. Another star appears to be an ellipsoidal variable with a 2.3-day orbital period; and two other systems have orbital periods longer than the āˆ¼4-year sampling interval of the Kepler data

    Development of an inducible mouse model of iRFP713 to track recombinase activity and tumour development in vivo

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    While the use of bioluminescent proteins for molecular imaging is a powerful technology to further our understanding of complex processes, fluorescent labeling with visible light fluorescent proteins such as GFP and RFP suffers from poor tissue penetration and high background autofluorescence. To overcome these limitations, we generated an inducible knock-in mouse model of iRFP713. This model was used to assess Cre activity in a Rosa Cre-ER background and quantify Cre activity upon different tamoxifen treatments in several organs. We also show that iRFP can be readily detected in 3D organoid cultures, FACS analysis and in vivo tumour models. Taken together we demonstrate that iRFP713 is a progressive step in in vivo imaging and analysis that widens the optical imaging window to the near-infrared spectrum, thereby allowing deeper tissue penetration, quicker image acquisition without the need to inject substrates and a better signal to background ratio in genetically engineered mouse models (GEMMs)

    Towards identifying factors underlying readiness for online learning: an exploratory study

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    To test the potential value of McVay\u27s (2000) Readiness for Online Learning questionnaire for research and practice, the instrument was administered to 107 undergraduate university students drawn from a range of courses in the United States and Australia. The questionnaire was subjected to a reliability analysis and a factor analysis. The instrument fared well in the reliability analysis, and yielded a two-factor structure that was readily interpretable in a framework of existing theory and research. Factors identified were &quot;Comfort with e-learning&quot; and &quot;Self-management of learning.&quot; It is suggested that the instrument is useful for both research and practice, but would be enhanced through further work on 5 of the 13 items. Additionally, further work is required to establish predictive validity.<br /

    The use of electronic voting systems in large group lectures: Challenges and opportunities

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    We describe pedagogical, technical and operational issues associated with the introduction of an electronic voting system into large first-year undergraduate lectures. The rationale for doing so is to transform the lecture experience from a one-way transmission of information in to a two-way conversation between lecturer and students, mediated by the technology. We discuss some of the logistics involved, such as choice of handset, cost and siting within a lecture theatre as well as the aspects of pedagogy, such as the requirements of a good question for these interactive episodes. We present a number of possible use scenarios and evaluate student and staff experiences of the process

    Adherence to a Mediterranean diet is associated with cognitive function in an older non- Mediterranean sample: findings from the Maine- Syracuse Longitudinal Study

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    Background: Adherence to a Mediterranean diet is associated with higher cognitive function and reduced risk of dementia in Mediterranean populations. However, few studies have investigated the association between Mediterranean diet adherence and cognition in populations outside of the Mediterranean basin. Furthermore, it is currently unknown whether the association between Mediterranean diet adherence and cognitive function differs between middle-aged and older individuals. Methods: Cross-sectional (n = 894) and longitudinal (n = 530) multivariable analyses were undertaken using data from community-dwelling adults from the Maine-Syracuse Longitudinal Study (MSLS). Mediterranean diet adherence was measured by applying a literature-based Mediterranean diet score to food frequency questionnaire data. Cognitive function was assessed with a battery of tests and composites scores were computed for global cognitive function, Visual-Spatial Organization and Memory, verbal memory, working memory, scanning, and tracking and abstract reasoning. Results: No cross-sectional associations between Mediterranean diet adherence and cognitive function were detected. Over a period of five years, higher adherence to a Mediterranean diet was associated with improvements in Global Cognitive Function, Visual-Spatial Organization and Memory and scanning and tracking in participants ā‰„70 years. No significant longitudinal associations were observed for participants \u3c70 years. Conclusion: Our findings suggest that higher adherence to a Mediterranean diet is associated with better cognitive performance, and therefore less cognitive decline, in older but not middle-aged individuals

    Adolescent girlsā€™ perceptions of their physical activity behaviors and social environment.

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    The purpose of this study was to explore how social relationships and environmental settings impact physical activity attitudes and behaviors for adolescent girls. Guided by a social ecological framework and following a phenomenological interpretive tradition, focus group interviews were conducted with 32 adolescent girls (17 African American, 15 Caucasian) between the ages of 11 and 13 who attended public middle schools. Adolescent girls indicated that parents and peers play a significant role in shaping their physical activity behaviors as does the physical and social environments in which they live. Themes that emerged from the analyses of data include (a) differing conceptualizations of physical activity, (b) parents and peers as facilitators of activity, (c) lack of girlsā€™ active space in school and neighborhood environments, and (d) policy restrictions on girlsā€™ access to physical activity time. African American girls reported conceiving of physical activity as unstructured play, often outside, where as White girls indicated they considered physical activity to be closely related to adult-directed, organized sport. Girls described a desire to engage in more physical activities with the mothers and other female relatives. A lack of playground space at school and unsafe community environments hindered the amount of activity in which girls engaged. Educational policies that prevent middle school girls from participating in school sport programs, as well as restricting recess and lunch periods to inside spaces impeded access to desired physical activity outlets by middle school girls in this study. Findings support previous research and extend understanding of girlsā€™ perceptions of physical activity by allowing girls to voice their opinions and concerns

    Adherence to a Mediterranean diet associated with lower blood pressure in a US sample: Findings from the Maine- Syracuse Longitudinal Study

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    Hypertension is a key modifiable risk factor for cardiovascular disease. The Mediterranean diet (MedDiet) may be associated with improvements in blood pressure. However, few studies have examined the association between MedDiet adherence and blood pressure in non-Mediterranean populations, and findings are mixed. We analyzed cross-sectional data (Wave 6) for 851 participants of the Maine-Syracuse Longitudinal Study. MedDiet adherence was calculated using food frequency questionnaire data and a literature-based MedDiet adherence score. Dependent variables included systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP). Separate linear robust regression analyses revealed significant associations between MedDiet adherence and for SBP (b = -0.69, 95% CI = [-1.25, -0.20]), DBP (b = -0.33, 95% CI = [-0.58, -0.04]), and MAP (b = -0.45, 95% CI = [-0.77, -0.11]), but not for PP. These findings indicate that the MedDiet is associated with some metrics of blood pressure in a large, community-based, non-Mediterranean sample

    Acute effects of an Avena sativa herb extract on responses to the Stroop Color-Word test

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    Background and aims: Extracts from oat (Avena sativa) herb may benefit cognitive performance. This study investigated whether NeuravenaĀ®, an oat herb extract, could acutely improve responses to the Stroop Colorā€“Word test, a measure of attention and concentration and the ability to maintain task focus.Ā  Subjects and methods: Elderly volunteers with below-average cognitive performance consumed single doses (0, 1600, and 2400ā€‰mg) of oat herb extract at weekly intervals in a double-blind, randomized, crossover comparison. Resting blood pressure (BP) was assessed before and after supplementation, and a Stroop test was performed.Ā  Results: Significantly fewer errors were made during the color-naming component of the Stroop test after consuming the 1600-mg dose than after the 0-mg or 2400-mg doses (F (1,36)=18.85, p<0.001). In 7 subjects with suspected cognitive impairment, Stroop interference score was also improved by the 1600-mg dose compared to 0- and 2400-mg doses (F (1, 34)=2.40, p<0.01). Resting BP was unaffected by supplementation.Ā  Conclusions: Taking 1600ā€‰mg of oat herb extract may acutely improve attention and concentration and the ability to maintain task focus in older adults with differing levels of cognitive status
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