4,886 research outputs found

    Every student counts: promoting numeracy and enhancing employability

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    This three-year project investigated factors that influence the development of undergraduates’ numeracy skills, with a view to identifying ways to improve them and thereby enhance student employability. Its aims and objectives were to ascertain: the generic numeracy skills in which employers expect their graduate recruits to be competent and the extent to which employers are using numeracy tests as part of graduate recruitment processes; the numeracy skills developed within a diversity of academic disciplines; the prevalence of factors that influence undergraduates’ development of their numeracy skills; how the development of numeracy skills might be better supported within undergraduate curricula; and the extra-curricular support necessary to enhance undergraduates’ numeracy skills

    Quantum Process Tomography of the Quantum Fourier Transform

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    The results of quantum process tomography on a three-qubit nuclear magnetic resonance quantum information processor are presented, and shown to be consistent with a detailed model of the system-plus-apparatus used for the experiments. The quantum operation studied was the quantum Fourier transform, which is important in several quantum algorithms and poses a rigorous test for the precision of our recently-developed strongly modulating control fields. The results were analyzed in an attempt to decompose the implementation errors into coherent (overall systematic), incoherent (microscopically deterministic), and decoherent (microscopically random) components. This analysis yielded a superoperator consisting of a unitary part that was strongly correlated with the theoretically expected unitary superoperator of the quantum Fourier transform, an overall attenuation consistent with decoherence, and a residual portion that was not completely positive - although complete positivity is required for any quantum operation. By comparison with the results of computer simulations, the lack of complete positivity was shown to be largely a consequence of the incoherent errors during the quantum process tomography procedure. These simulations further showed that coherent, incoherent, and decoherent errors can often be identified by their distinctive effects on the spectrum of the overall superoperator. The gate fidelity of the experimentally determined superoperator was 0.64, while the correlation coefficient between experimentally determined superoperator and the simulated superoperator was 0.79; most of the discrepancies with the simulations could be explained by the cummulative effect of small errors in the single qubit gates.Comment: 26 pages, 17 figures, four tables; in press, Journal of Chemical Physic

    Unexpected Nickel Complex Speciation Unlocks Alternative Pathways for the Reactions of Alkyl Halides with dppf-Nickel(0)

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    The mechanism of the reactions between dppf-Ni0 complexes and alkyl halides has been investigated using kinetic and mechanistic experiments and DFT calculations. The active species is [Ni(κ2-dppf)(κ1-dppf)], which undergoes a halide abstraction reaction with alkyl halides and rapidly captures the alkyl radical that is formed. The rates of the reactions of [Ni(COD)(dppf)] with alkyl halides and the yields of prototypical nickel-catalyzed Kumada cross-coupling reactions of alkyl halides are shown to be significantly improved by the addition of free dppf ligand

    Luminescent 1,8-Naphthalimide-Derived ReI Complexes: syntheses, spectroscopy, X-ray structure and preliminary bioimaging in fission yeast cells

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    A series of picolyl-functionalised, fluorescent 1,8-naphthalimide ligands (L) have been synthesised and coordi-nated to ReI to form luminescent cationic complexes of the general form fac-[Re(phen)(CO)3(L)]BF4. The complexes were characterised by using a range of spectroscopic and analytical techniques. One example of a complex was also characterised in the solid-state by using single-crystal X-ray diffraction, reveal-ing a distorted octahedral coordination sphere at ReI and Re– C/Re–N bond lengths within the expected ranges. All ligands were shown to be fluorescent, with the 4-amino derivatives showing intramolecular charge transfer in the visible region (511–534 nm). The complexes generally showed a mixture of ligand-centred and/or 3MLCT emission depending upon the na-ture of the coordinated 1,8-naphthalimide ligand. For selected complexes, confocal fluorescence microscopy was undertaken by using fission yeast cells (Schizosaccharomyces pombe) and showed that the structure of the 1,8-naphthalimide ligand influ-ences the uptake and localisation of the rhenium complex

    Association of 6-Minute Walk Performance and Physical Activity With Incident Ischemic Heart Disease Events and Stroke in Peripheral Artery Disease.

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    BackgroundWe determined whether poorer 6-minute walk performance and lower physical activity levels are associated with higher rates of ischemic heart disease (IHD) events in people with lower extremity peripheral artery disease (PAD).Methods and resultsFive hundred ten PAD participants were identified from Chicago-area medical centers and followed prospectively for 19.0±9.5 months. At baseline, participants completed the 6-minute walk and reported number of blocks walked during the past week (physical activity). IHD events were systematically adjudicated and consisted of new myocardial infarction, unstable angina, and cardiac death. For 6-minute walk, IHD event rates were 25/170 (14.7%) for the third (poorest) tertile, 10/171 (5.8%%) for the second tertile, and 6/169 (3.5%) for the first (best) tertile (P=0.003). For physical activity, IHD event rates were 21/154 (13.6%) for the third (poorest) tertile, 15/174 (8.6%) for the second tertile, and 5/182 (2.7%) for the first (best) tertile (P=0.001). Adjusting for age, sex, race, smoking, body mass index, comorbidities, and physical activity, participants in the poorest 6-minute walk tertile had a 3.28-fold (95% CI 1.17 to 9.17, P=0.024) higher hazard for IHD events, compared with those in the best tertile. Adjusting for confounders including 6-minute walk, participants in the poorest physical activity tertile had a 3.72-fold (95% CI 1.24 to 11.19, P=0.019) higher hazard for IHD events, compared with the highest tertile.ConclusionsSix-minute walk and physical activity predict IHD event rates in PAD. Further study is needed to determine whether interventions that improve 6-minute walk, physical activity, or both can reduce IHD events in PAD

    FAK induces expression of Prx1 to promote tenascin-C–dependent fibroblast migration

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    Fibroblast migration depends, in part, on activation of FAK and cellular interactions with tenascin-C (TN-C). Consistent with the idea that FAK regulates TN-C, migration-defective FAK-null cells expressed reduced levels of TN-C. Furthermore, expression of FAK in FAK-null fibroblasts induced TN-C, whereas inhibition of FAK activity in FAK–wild-type cells had the opposite effect. Paired-related homeobox 1 (Prx1) encodes a homeobox transcription factor that induces TN-C by interacting with a binding site within the TN-C promoter, and it also promotes fibroblast migration. Therefore, we hypothesized that FAK regulates TN-C by controlling the DNA-binding activity of Prx1 and/or by inducing Prx1 expression. Prx1–homeodomain binding site complex formation observed with FAK–wild-type fibroblasts failed to occur in FAK-null fibroblasts, yet expression of Prx1 in these cells induced TN-C promoter activity. Thus, FAK is not essential for Prx1 DNA-binding activity. However, activated FAK was essential for Prx1 expression. Functionally, Prx1 expression in FAK-null fibroblasts restored their ability to migrate toward fibronectin, in a manner that depends on TN-C. These results appear to be relevant in vivo because Prx1 and TN-C expression levels were reduced in FAK-null embryos. This paper suggests a model whereby FAK induces Prx1, and subsequently the formation of a TN-C–enriched ECM that contributes to fibroblast migration

    Microbiota‐Dependent Metabolite Trimethylamine N‐Oxide and Coronary Artery Calcium in the Coronary Artery Risk Development in Young Adults Study (CARDIA)

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    BACKGROUND: Clinical studies implicate trimethylamine N-oxide (TMAO; a gut microbiota-dependent nutrient metabolite) in cardiovascular disease risk. There is a lack of population-based data on the role of TMAO in advancing early atherosclerotic disease. We tested the prospective associations between TMAO and coronary artery calcium (CAC) and carotid intima-media thickness (cIMT). METHODS AND RESULTS: Data were from the Coronary Artery Risk Development in Young Adults Study (CARDIA), a biracial cohort of US adults recruited in 1985-1986 (n=5115). We randomly sampled 817 participants (aged 33-55 years) who attended examinations in 2000-2001, 2005-2006, and 2010-2011, at which CAC was measured by computed tomography and cIMT (2005-2006) by ultrasound. TMAO was quantified using liquid chromotography mass spectrometry on plasma collected in 2000-2001. Outcomes were incident CAC, defined as Agatston units=0 in 2000-2001 and >0 over 10-year follow-up, CAC progression (any increase over 10-year follow-up), and continuous cIMT. Over the study period, 25% (n=184) of those free of CAC in 2000-2001 (n=746) developed detectable CAC. In 2000-2001, median (interquartile range) TMAO was 2.6 (1.8-4.2) μmol/L. In multivariable-adjusted models, TMAO was not associated with 10-year CAC incidence (rate ratio=1.03; 95% CI: 0.71-1.52) or CAC progression (0.97; 0.68-1.38) in Poisson regression, or cIMT (beta coefficient: -0.009; -0.03 to 0.01) in linear regression, comparing the fourth to the first quartiles of TMAO. CONCLUSIONS: In this population-based study, TMAO was not associated with measures of atherosclerosis: CAC incidence, CAC progression, or cIMT. These data indicate that TMAO may not contribute significantly to advancing early atherosclerotic disease risk among healthy early-middle-aged adults

    Associations of cortisol/testosterone and cortisol/sex hormone-binding globulin ratios with atherosclerosis in middle-age women

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    AbstractBackground and aimsThe cortisol/testosterone (C/T) ratio has been hypothesized to be a better predictor of atherosclerosis than cortisol alone. No study has assessed whether the C/T and C/sex hormone-binding globulin (SHBG) ratios are associated with atherosclerosis in a U.S. population sample.MethodsThis substudy included 367 women who had both cortisol from year 15 and testosterone and SHBG at year 16 of the Coronary Artery Risk Development in Young Adults study, an ongoing observational cohort in the United States. Of these, intima-media thickness (IMT) was available at follow-up year 20 in 339 (n = 332 with measurement at carotid bulb), and 303 were free of prevalent coronary artery calcium (CAC) at year 15. Area under the curve (AUC) of salivary cortisol was available in 302 individuals. Ratios of AUCs of cortisol to total testosterone, free testosterone, and SHBG were categorized into tertiles. Associations with CAC and IMT were assessed by regression models adjusted for age, race, body mass index, systolic blood pressure, menopause, oral contraceptive use, diabetes, alcohol, and smoking.ResultsOnly the highest tertile of the AUC/free testosterone ratio was positively associated with carotid bulb IMT (β = 0.088, P = 0.006). This tertile was also positively associated with new onset CAC between year 15 and 25 (OR 3.45, 95% CI 1.18–10.06). Tertiles of cortisol or testosterone alone were not associated with new onset CAC.ConclusionAUC/Free testosterone ratio may be more associated with atherosclerosis in women than either indicator alone. The ratio may serve as a suitable biomarker of cortisol-linked stress
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