1,422 research outputs found

    Experimental Studies of the NaCs 53Π0 and a3Σ+ States

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    We report high resolution measurements of 372 NaCs 53Π0(v, J) ro-vibrational level energies in the range 0 ≤ v ≤ 22. The data have been used to construct NaCs 53Π0 potential energy curves using the Rydberg–Klein-Rees and inverted perturbation approximation methods. Bound-free 53Π0(v, J) → 1(a)3Σ+ emission has also been measured, and is used to determine the repulsive wall of the 1(a)3Σ+ state and the 53Π0 → 1(a)3Σ+ relative transition dipole moment function. Hyperfine structure in the 53Π0 state has not been observed in this experiment. This null result is explained using a simple vector coupling model

    Patient safety and estimation of renal function in patients prescribed new oral anticoagulants for stroke prevention in atrial fibrillation

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    OBJECTIVE: In clinical trials of dabigatran and rivaroxaban for stroke prevention in atrial fibrillation (AF), drug eligibility and dosing were determined using the Cockcroft-Gault equation to estimate creatine clearance as a measure of renal function. This cross-sectional study aimed to compare whether using estimated glomerular filtration rate (eGFR) by the widely available and widely used Modified Diet in Renal Disease (MDRD) equation would alter prescribing or dosing of the renally excreted new oral anticoagulants. PARTICIPANTS: Of 4712 patients with known AF within a general practitioner-registered population of 930 079 in east London, data were available enabling renal function to be calculated by both Cockcroft-Gault and MDRD methods in 4120 (87.4%). RESULTS: Of 4120 patients, 2706 were <80 years and 1414 were ≥80 years of age. Among those ≥80 years, 14.9% were ineligible for dabigatran according to Cockcroft-Gault equation but would have been judged eligible applying MDRD method. For those <80 years, 0.8% would have been incorrectly judged eligible for dabigatran and 5.3% would have received too high a dose. For rivaroxaban, 0.3% would have been incorrectly judged eligible for treatment and 13.5% would have received too high a dose. CONCLUSIONS: Were the MDRD-derived eGFR to be used instead of Cockcroft-Gault in prescribing these new agents, many elderly patients with AF would either incorrectly become eligible for them or would receive too high a dose. Safety has not been established using the MDRD equation, a concern since the risk of major bleeding would be increased in patients with unsuspected renal impairment. Given the potentially widespread use of these agents, particularly in primary care, regulatory authorities and drug companies should alert UK doctors of the need to use the Cockcroft-Gault formula to calculate eligibility for and dosing of the new oral anticoagulants in elderly patients with AF and not rely on the MDRD-derived eGFR

    Slope of the topological susceptibility at zero temperature and finite temperature in the Nambu-Jona-Lasinio model

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    We estimate the slope of the topological susceptibility in the three flavour Nambu-Jona-Lasinio model with the 't Hooft interaction. The results are consistent with the evaluation from the QCD sum rule in favour of the full topological susceptibility. We apply it to the Shore-Veneziano formula to find that it shows satisfactory agreement with the anomalous suppression of the flavour-singlet axial charge. The behaviour at finite temperature is also discussed.Comment: 8 pages, 3 figures, submitted to Phys. Lett.

    The Richness of the Globular Cluster System of NGC 3923: Clues to Elliptical Galaxy Formation

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    We present new data on the globular cluster system of the elliptical galaxy NGC 3923 which show that it has the most globular clusters per unit luminosity of any non-cluster elliptical yet observed, with SN=6.4±1.4S_N=6.4 \pm1.4. NGC 3923 is also among the brightest ellipticals outside of a galaxy cluster for which the number of globular clusters has been determined. Our observation of a large number of clusters per unit luminosity (high SNS_N value) for a bright elliptical in a sparse environment is consistent with the suggestion of Djorgovski \& Santiago that the number of globular clusters is a power law function of the luminosity with an exponent greater than one. We relate this higher specific frequency of globular clusters in more luminous galaxies to other observations which indicate that the physical conditions within elliptical galaxies at the time of their formation were dependent on galaxy mass.Comment: 13 pages + 3 figures, uuencoded postscript, to appear in ApJ Letters, UC-BERK-9

    Indexing dialysis dose for gender, body size and physical activity: Impact on survival

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    Current practice basing dialysis dose on urea distribution volume (V) has been questioned. We explored the impact on survival of scaling dialysis dose (Kt) to parameters reflective of metabolic activity. In a multicentre prospective cohort study of 1500 patients on thrice-weekly haemodialysis, body surface area (BSA) and resting energy expenditure (REE) were estimated using validated equations and physical activity by the Recent Physical Activity Questionnaire. Total energy expenditure (TEE) was estimated from REE and physical activity data. Kt was calculated from delivered (single-pool Kt/V)*Watson V. Kt/BSA, Kt/ REE and Kt/TEE were then calculated at baseline and 6 monthly during follow-up for 2 years. In adjusted Cox models Kt/TEE, Kt/BSA, Kt/REE, in that order, had lower hazard ratios for death than single-pool Kt/V. On the basis of adjusted survival differences, putative minimum target doses were estimated for Kt/BSA as 27119 ml/m 2 and Kt/TEE as 25.79 ml/ kcal. We identified spKt/V values equivalent to these estimated targets, ranging from 1.4 to 1.8 in patient groups based on gender, body size and physical activity. For sedentary patients, the minimum target dose was 1.4 for large males, 1.5 for small males and 1.7 for women. For active patients the target was 1.8 irrespective of gender and body-weight. Patients achieving these individualised minimum targets had greater adjusted two-year survival compared to those achieving conventional minimum targets. Metabolic activity related parameters, such as Kt/TEE and Kt/BSA, may have a clinically important role in scaling haemodialysis dose. Using such parameters or their spKt/V equivalents to adjust minimum target doses based on gender, body size and habitual physical activity may have a positive impact on survival.Peer reviewe

    Production of J/ψJ/\psi-pairs at HERA-N\vec{{\rm N}}

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    The production of J/ψJ/\psi-pairs as a possible measure of the polarized gluon distribution ΔG(x)\Delta G(x) is studied for proton--nucleon collisions at \sqrt{s} =40\;\mbox{GeV}^2 (HERA-N\vec{{\rm N}}). Possibilities of reconstructing the helicity state of at least one of the J/ψJ/\psi's are critically reviewed. The observation of production asymmetries in the single polarized mode of HERA-N\vec{{\rm N}} is found to be not feasible.Comment: 8 pages, LATeX, 3 figures availabe as .uu-fil

    Ab-initio simulations on growth and interface properties of epitaxial oxides on silicon

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    The replacement of SiO2 by so-called high-k oxides is one of the major challenges for the semiconductor industry to date. Based on electronic structure calculations and ab-initio molecular dynamics simulations, we are able to provide a consistent picture of the growth process of a class of epitaxial oxides around SrO and SrTiO3. The detailed understanding of the interfacial binding principles has also allowed us to propose a way to engineer the band-offsets between the oxide and the silicon substrate.Comment: 6 pages, 6 figures, proceeding for the INFOS2005 conference (http://www.imec.be/infos/

    Gamma^*, Z^* production in polarised p-p scattering as a probe of the proton spin structure

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    We present the results of a detailed study of the large transverse momentum Drell-Yan process, pp --> (Gamma^*, Z^*)X --> l^+l^- X at collider energies, with either one or both protons polarised, allowing the study of single- and double-spin asymmetries respectively. We show how these asymmetries obtained from angular distributions of the leptons in the Gamma^* (or Z^*) rest-frame, can be used to get information on the polarised parton distributions. Numerical results for the asymmetries and the cross-sections are presented, and the sensitivity of the asymmetries to the initial parton distributions indicates that these can be used as effective probes of the spin structure of the proton.Comment: Latex, 9 pages, 4 figures available on request, CERN-TH.6997/9

    The influence of image interactivity upon user engagement when using mobile touch screens

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    Touch screens are a key component of consumer mobile devices such as smartphones and tablets, as well as an increasingly common self-service component of information retrieval on fixed screens and mobile devices in-store. The ubiquity of touch screens in daily life increases consumer accessibility and extended use for shopping, whilst software innovations have increased the functionality of touch screens, for example the extent to which images respond to fingertip control. This study examines how users engage with interactive visual rotation and tactile simulation features while browsing fashion clothing products on touch screen devices and thus contributes to retail touch screen research that previously focused on in-store kiosks and window displays. Findings show that three dimensions of user engagement (endurability, novelty and felt involvement) are positively influenced by both forms of manipulation. In order to examine the extent to which touch screen user engagement varies with individual preferences for an in-store experience, the paper also examines whether user engagement outcomes are mediated by an individual's need for physical touch. Findings indicate that the need for touch does not explain the variance between individuals. We conclude that touch screen technology complements the physical retail environment
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