594 research outputs found

    A new subsurface record of the Pliensbachian-Toarcian, Lower Jurassic, of Yorkshire

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    Here, we describe the upper Pliensbachian to middle Toarcian stratigraphy of the Dove's Nest borehole, which was drilled near Whitby, North Yorkshire, in 2013. The core represents a single, continuous vertical section through unweathered, immature Lower Jurassic sedimentary rocks. The thickness of the Lias Group formations in the Dove's Nest core is approximately the same as that exposed along the North Yorkshire coast between Hawsker Bottoms and Whitby. The studied succession consists of epeiric-neritic sediments and comprises cross-laminated very fine sandstones, (oolitic) ironstones, and argillaceous mudstones. Dark argillaceous mudstone is the dominant lithology. These sediments were deposited in the Cleveland Basin, a more subsident area of an epeiric sea, the Laurasian Sea. We present a set of geochemical data that includes organic carbon isotope ratios (δ13Corg) and total organic carbon (TOC). The δ13Corg record contains a negative excursion across the Pliensbachian–Toarcian boundary and another in the lower Toarcian that corresponds to the Toarcian Oceanic Anoxic Event (T-OAE). Below the T-OAE negative excursion, δ13Corg values are less 13C-depleted than above it. We find no evidence of a long-term δ13Corg positive excursion. TOC values below the T-OAE negative excursion are lower than above it. Sedimentary evidence suggests that, during much of the Pliensbachian–Toarcian interval, the seafloor of the Cleveland Basin was above storm wave-base and that storm-driven bottom currents were responsible for much sediment erosion, transport, and redeposition during the interval of oceanic anoxia. The abrupt shifts observed in the δ13Corg record (lower Toarcian) are likely to reflect the impact of erosion by storms on the morphology of the δ13C record of the T-OAE

    Dynamic Control of Photoresponse in ZnO-Based Thin-Film Transistors in the Visible Spectrum

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    Cataloged from PDF version of article.We present ZnO-channel thin-film transistors with actively tunable photocurrent in the visible spectrum, although ZnO band edge is in the ultraviolet. ZnO channel is deposited by atomic layer deposition technique at a low temperature (80 C), which is known to introduce deep level traps within the forbidden band of ZnO. The gate bias dynamically modifies the occupancy probability of these trap states by controlling the depletion region in the ZnO channel. Unoccupied trap states enable the absorption of the photons with lower energies than the bandgap of ZnO. Photoresponse to visible light is controlled by the applied voltage bias at the gate terminal

    Plasmonically enhanced hot electron based photovoltaic device

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    Cataloged from PDF version of article.Hot electron photovoltaics is emerging as a candidate for low cost and ultra thin solar cells. Plasmonic means can be utilized to significantly boost device efficiency. We separately form the tunneling metal-insulator-metal (MIM) junction for electron collection and the plasmon exciting MIM structure on top of each other, which provides high flexibility in plasmonic design and tunneling MIM design separately. We demonstrate close to one order of magnitude enhancement in the short circuit current at the resonance wavelengths. (C) 2013 Optical Society of Americ

    Comparative effectiveness of enalapril, lisinopril, and ramipril in the treatment of patients with chronic heart failure: a propensity score-matched cohort study

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    Background: Angiotensin converting enzyme inhibitors (ACEIs) are recommended as first-line therapy in patients with heart failure with reduced ejection fraction (HFrEF). The comparative effectiveness of different ACEIs is not known. Methods and results: 4,723 out-patients with stable HFrEF prescribed either enalapril, lisinopril, or ramipril were identified from three registries in Norway, England, and Germany. In three separate matching procedures, patients were individually matched with respect to both dose equivalents and their respective propensity scores for ACEI treatment. During a follow-up of 21,939 patient-years, 360 (49.5%), 337 (52.4%), and 1,119 (33.4%) patients died amongst those prescribed enalapril, lisinopril, and ramipril, respectively. In univariable analysis of the general sample, enalapril and lisinopril were both associated with higher mortality as compared with ramipril treatment (HR 1.46, 95% CI 1.30-1.65, p < 0.001, and HR 1.38, CI 1.22-1.56, p < 0.001, respectively). Patients prescribed enalapril or lisinopril had similar mortality (HR 1.06, 95% CI 0.92-1.24, p = 0.41). However, there was no significant association between ACEI choice and all-cause mortality in any of the matched samples (HR 1.07, 95% CI 0.91-1.25, p = 0.40; HR 1.12, 95% CI 0.96-1.32, p = 0.16; and HR 1.08, HR 1.10, 95% CI 0.93-1.31, p = 0.25 for enalapril vs. ramipril, lisinopril vs. ramipril, and enalapril vs. lisinopril, respectively). Results were confirmed in subgroup analyses with respect to age, sex, left ventricular ejection fraction, NYHA functional class, cause of HFrEF, rhythm, and systolic blood pressure. Conclusion: Our results suggest that enalapril, lisinopril and ramipril are equally effective in the treatment of patients with HFrEF when given at equivalent doses

    Direct Reactions with Light Neutron-Rich Nuclei

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    Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

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    The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 21+ state of 16,18,20C. The experimental findings support the notion of a moderate reduction of the proton 1p1/2−1p3/2 spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline.</p

    On Robustness of Discrete Time Optimal Filters

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    A new result on stability of an optimal nonlinear filter for a Markov chain with respect to small perturbations on every step is established. An exponential recurrence of the signal is assumed

    Comparative efficacy of sodium-glucose cotransporter-2 inhibitors (SGLT2i) for cardiovascular outcomes in type 2 diabetes: a systematic review and network meta-analysis of randomised controlled trials

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    Sodium-glucose cotransporter-2 inhibitors (SGLT2i) improve cardiovascular outcomes in patients with type 2 diabetes mellitus (T2D). The comparative efficacy of individual SGLT2i remains unclear. We searched PubMed, www.clinicaltrials.gov and the Cochrane Central Register of Controlled Trials for randomised controlled trials exploring the use of canagliflozin, dapagliflozin, empagliflozin or ertugliflozin in patients with T2D. Comparators included placebo or any other active treatment. The primary endpoint was all-cause mortality. Secondary endpoints were cardiovascular mortality and worsening heart failure (HF). Evidence was synthesised using network meta-analysis (NMA). Sixty-four trials reporting on 74,874 patients were included. The overall quality of evidence was high. When compared with placebo, empagliflozin and canagliflozin improved all three endpoints, whereas dapagliflozin improved worsening HF. When compared with other SGLT2i, empagliflozin was superior for all-cause and cardiovascular mortality reduction. Empagliflozin, canagliflozin and dapagliflozin had similar effects on improving worsening HF. Ertugliflozin had no effect on any of the three endpoints investigated. Sensitivity analyses including extension periods of trials or excluding studies with a treatment duration of &lt; 52 weeks confirmed the main results. Similar results were obtained when restricting mortality analyses to patients included in cardiovascular outcome trials (n = 38,719). Empagliflozin and canagliflozin improved survival with empagliflozin being superior to the other SGLT2i. Empagliflozin, canagliflozin and dapagliflozin had similar effects on improving worsening HF. Prospective head-to-head comparisons would be needed to confirm these results
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