1,025 research outputs found

    Portable X‐ray fluorescence spectroscopy as a tool for cyclostratigraphy

    Get PDF
    Cyclostratigraphic studies are used to create relative and high‐resolution timescales for sedimentary successions based on identification of regular cycles in climate proxy data. This method typically requires the construction of long high‐resolution datasets. In this study, we have demonstrated the efficacy of portable X‐ray fluorescence spectroscopy (pXRF) as a non‐destructive method of generating compositional data for cyclostratigraphy. The rapidity (100 samples per day) and low cost of pXRF measurements provide advantages over relatively time‐consuming and costly elemental and stable isotopic measurements that are commonly used for cyclostratigraphy. The non‐destructive nature of pXRF also allows other geochemical analyses on the same samples. We present an optimized protocol for pXRF elemental concentration measurement in powdered rocks. The efficacy of this protocol for cyclostratigraphy is demonstrated through analysis of 360 Toarcian mudrock samples from North Yorkshire, UK, that were previously shown to exhibit astronomical forcing of [CaCO3], [S] and δ13Corg. Our study is the first to statistically compare the cyclostratigraphic results of pXRF analysis with more established combustion analysis. There are strong linear correlations of pXRF [Ca] with dry combustion elemental analyzer [CaCO3] (r2=0.7616), and pXRF [S] and [Fe] with dry combustion elemental analyzer [S] (r2=0.9632 and r2=0.9274 respectively). Spectral and cross‐spectral analysis demonstrates that cyclicity previously recognized in [S], significant above the 99.99% confidence level, is present above the 99.92% and 99.99% confidence levels in pXRF [S] and [Fe] data respectively. Cyclicity present in [CaCO3] data above the 99.96% confidence level is also present in pXRF [Ca] above the 98.12% confidence level

    The HF-CGM study: An analysis of cardiogoniometric axes in patients with cardiac resynchronization therapy

    Get PDF
    Goal: The HF-CGM is a proof-of-principle study to investigate whether cardiogoniometry (CGM), a three-dimensional electrocardiographic method, can differentiate between pacing modes in patients with cardiac resynchronization therapy (CRT). Methods: At a tertiary cardiology center, CGM recordings were performed using four pacing modes: no pacing; right ventricular (RV) pacing; left ventricular (LV) pacing, and biventricular (BIV) pacing. Three orthogonal CGM planes orientated to the long axis (XY), the frontal plane (YZ), and the short axis (XZ) of the heart were constructed, and the direction of the QRS-axis was calculated for each pacing mode in each plane. During BIV pacing, the direction of CGM QRS-axis was compared between patients with optimal and nonoptimal 12-lead pacing variables. Results: Twenty-two participants (aged 71.5 ± 10.8; 77.3% male, LVEF 29 ± 7%) were consecutively recruited. Only QRS-axis measured in the XY plane could significantly distinguish between all three pacing modes versus no pacing. Mean QRS-axis in the XY plane with pacing off and during RV pacing was leftward and basal; LV pacing was apical; and BIV pacing was rightward and basal. There was a statistically significant difference in the direction of the QRS-axis between patients with optimal versus nonoptimal paced QRS morphology in the XY plane (rightward and basal versus inconsistent). Significance : CGM recorded in the XY plane can accurately detect differences between ventricular pacing sites. It may also be able to identify patients with a CRT device in situ who have optimal response

    The difference in blood pressure readings between arms and survival: primary care cohort study

    Get PDF
    Objective To determine whether a difference in systolic blood pressure readings between arms can predict a reduced event free survival after 10 years

    Generalized AdS/CFT Dualities and Space-Time Symmetries of M/Superstring Theory

    Full text link
    I review the relationship between AdS/CFT (anti-de Sitter / conformal field theory) dualities and the general theory of unitary lowest weight (ULWR) (positive energy) representations of non-compact space-time groups and supergroups. The ULWR's have the remarkable property that they can be constructed by tensoring some fundamental ULWR's (singletons or doubletons). Furthermore, one can go from the manifestly unitary compact basis of the ULWR's of the conformal group (Wigner picture) to the manifestly covariant coherent state basis (Dirac picture) labelled by the space-time coordinates. Hence every irreducible ULWR corresponds to a covariant field with a definite conformal dimension. These results extend to higher dimensional generalized spacetimes (superspaces) defined by Jordan (super) algebras and Jordan (super) triple systems. In particular, they extend to the ULWR's of the M-theory symmetry superalgebra OSp(1/32,R).Comment: Latex file, 11 pages; invited talk to appear in the Proceedings of the IXth Marcel Grossmann Meeting (Rome, July 2000

    Influence of case definition on incidence and outcome of acute coronary syndromes

    Get PDF
    © 2016, BMJ Publishing Group. All rights reserved. Objective: Acute coronary syndromes (ACS) are common, but their incidence and outcome might depend greatly on how data are collected. We compared case ascertainment rates for ACS and myocardial infarction (MI) in a single institution using several different strategies. Methods: The Hull and East Yorkshire Hospitals serve a population of ∼560 000. Patients admitted with ACS to cardiology or general medical wards were identified prospectively by trained nurses during 2005. Patients with a death or discharge code of MI were also identified by the hospital information department and, independently, from Myocardial Infarction National Audit Project (MINAP) records. The hospital laboratory identified all patients with an elevated serum troponin-T (TnT) by contemporary criteria ( > 0.03 μg/L in 2005). Results: The prospective survey identified 1731 admissions (1439 patients) with ACS, including 764 admissions (704 patients) with MIs. The hospital information department reported only 552 admissions (544 patients) with MI and only 206 admissions (203 patients) were reported to the MINAP. Using all 3 strategies, 934 admissions (873 patients) for MI were identified, for which TnT was > 1 μg/L in 443, 0.04-1.0 μg/L in 435, =0.03 μg/L in 19 and not recorded in 37. A further 823 patients had TnT > 0.03 μg/L, but did not have ACS ascertained by any survey method. Of the 873 patients with MI, 146 (16.7%) died during admission and 218 (25.0%) by 1 year, but ranging from 9% for patients enrolled in the MINAP to 27% for those identified by the hospital information department. Conclusions: MINAP and hospital statistics grossly underestimated the incidence of MI managed by our hospital. The 1-year mortality was highly dependent on the method of ascertainment

    Chromophoric Dissolved Organic Matter and Dissolved Organic Carbon in Lakes Across an Elevational Gradient From the Mountains to the Sea

    Get PDF
    Dissolved organic matter (DOM) in lakes across elevation gradients is a complex function of topography, climate, vegetation coverage, land use, and lake properties. To examine sources and processing of DOM from sea level to mountain lakes (3–1,574 m), we measured dissolved organic carbon (DOC) concentrations and chromophoric dissolved organic matter (CDOM) optical properties, lake characteristics, and water quality parameters in 62 freshwater lakes in the Pacific Northwest, USA. Higher elevation lakes had lower DOC concentrations and absorbance. These lakes had higher forest cover and minimal wetlands in their watershed, in addition to low nutrients, water temperatures, and chlorophyll a in the lake itself. Two humic-like and one protein-like fluorescent component were identified from excitation-emission matrix spectroscopy. The index of recent autochthonous contribution (BIX), fluorescence index (FIX), and SR optical indices showed that most lakes were dominated by terrestrially derived material. The humification index (HIX) and specific ultra-violet absorbance (SUVA254) were consistent with more aromatic humic CDOM at lower elevations. The lower fluorescence of humic-like components at higher elevation was attributed to lower inputs from vegetation. The relative contribution of the protein-like component increased at higher elevation. This may be due to reduced allochthonous terrestrial inputs relative to in situ production of autochthonous material or increased photochemical/biological degradation of allochthonous material. Differences in optical characteristics associated with the amount and source of CDOM were observed across the elevational gradient. These differences were driven by characteristics at both within-lake and watershed scales

    Reducing Stress after Trauma (ReSeT): Study Protocol for a Randomized, Controlled Trial of an Online Psychoeducational Program and Video Therapy Sessions for Children Hospitalized after Trauma

    Get PDF
    BACKGROUND: Post-traumatic stress symptoms develop in a quarter to half of injured children affecting their longer-term psychologic and physical health. Evidence-based care exists for post-traumatic stress; however, it is not readily available in some communities. We have developed an eHealth program consisting of online, interactive educational modules and telehealth therapist support based in trauma-focused cognitive behavioral therapy, the Reducing Stress after Trauma (ReSeT) program. We hypothesize that children with post-traumatic stress who participate in ReSeT will have fewer symptoms compared to the usual care control group. METHODS: This is a randomized controlled trial to test the effectiveness of the ReSeT intervention in reducing symptoms of post-traumatic stress compared to a usual care control group. One hundred and six children ages 8-17 years, who were admitted to hospital following an injury, with post-traumatic stress symptoms at 4 weeks post-injury, will be recruited and randomized from the four participating trauma centers. The outcomes compared across groups will be post-traumatic stress symptoms at 10 weeks (primary outcome) controlling for baseline symptoms and at 6 months post-randomization (secondary outcome). DISCUSSION: ReSeT is an evidence-based program designed to reduce post-traumatic stress symptoms among injured children using an eHealth platform. Currently, the American College of Surgeons standards suggest that trauma programs identify and treat patients at high risk for mental health needs in the trauma system. If effectiveness is demonstrated, ReSeT could help increase access to evidence-based care for children with post-traumatic stress within the trauma system

    Bis[(1S*,2S*)-trans-1,2-bis­(diphenyl­phosphin­oxy)cyclo­hexa­ne]chlorido­ruthenium(II) trifluoro­methane­sulfonate dichloro­methane disolvate

    Get PDF
    The crystal structure of a racemic mixture of the title ruthenium(II) complex, [RuCl(C30H30O2P2)2]CF3SO3·2CH2Cl2, reveals that the coordination geometry about the coordinatively unsaturated metal centre is approximately trigonal-pyramidal, with the chlorine atom occupying one of the equatorial positions. The axial Ru—P bonds are longer than the equatorial Ru—P bonds and there is an acute P—Ru—P angle
    corecore