115 research outputs found

    E-Type Delayed Fluorescence of a Phosphine-Supported Cu_2(μ-NAr_2)_2 Diamond Core: Harvesting Singlet and Triplet Excitons in OLEDs

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    A highly emissive bis(phosphine)diarylamido dinuclear copper(I) complex (quantum yield = 57%) was shown to exhibit E-type delayed fluorescence by variable temperature emission spectroscopy and photoluminescence decay measurement of doped vapor-deposited films. The lowest energy singlet and triplet excited states were assigned as charge transfer states on the basis of theoretical calculations and the small observed S_1−T_1 energy gap. Vapor-deposited OLEDs doped with the complex in the emissive layer gave a maximum external quantum efficiency of 16.1%, demonstrating that triplet excitons can be harvested very efficiently through the delayed fluorescence channel. The function of the emissive dopant in OLEDs was further probed by several physical methods, including electrically detected EPR, cyclic voltammetry, and photoluminescence in the presence of applied current

    Towards integration of general practitioner posts and accident and emergency departments: a case study of two integrated emergency posts in the Netherlands

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    <p>Abstract</p> <p>Background</p> <p>Accident and emergency (A&E) departments and general practitioner (GP) posts are often used inappropriately, leading to overcrowding. In the Netherlands, increasingly more integrated emergency posts (IEPs) are being created, integrating the care provided by GP posts and A&E departments, in order to improve the provision of the emergency care.</p> <p>Methods</p> <p>This explorative study compares the efficiency and patient and employee satisfaction in IEPs with those in two GP posts and two A&E departments. To this end, information was retrieved from hospital and GP patient records for the first quarter of the year before and of the year after the creation of IEPs. Patients and employees were sent a questionnaire to measure their satisfaction. Lastly, groups of hospital doctors, GPs, GP assistants, and nurses were interviewed.</p> <p>Results</p> <p>After the creation of IEPs, there was a shift of more than fifteen percent from secondary care to primary care for emergency consultations and waiting/consultation times were shortened by more than ten percent. Compared with the control settings, patients were more satisfied about telephone contact with an IEP, but professionals working at the IEP were less satisfied with several aspects of their work.</p> <p>Conclusion</p> <p>IEPs could be a promising innovation to organize emergency care more efficiently; however, it might take time to convince professionals of the possible advantages. Studies involving more IEPs and longer follow-up times are needed to determine whether such integration should be stimulated.</p

    Peak grain forecasts for the US High Plains amid withering waters

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    Irrigated agriculture contributes 40% of total global food production. In the US High Plains, which produces more than 50 million tons per year of grain, as much as 90% of irrigation originates from groundwater resources, including the Ogallala aquifer. In parts of the High Plains, groundwater resources are being depleted so rapidly that they are considered nonrenewable, compromising food security. When groundwater becomes scarce, groundwater withdrawals peak, causing a subsequent peak in crop production. Previous descriptions of finite natural resource depletion have utilized the Hubbert curve. By coupling the dynamics of groundwater pumping, recharge, and crop production, Hubbert-like curves emerge, responding to the linked variations in groundwater pumping and grain production. On a state level, this approach predicted when groundwater withdrawal and grain production peaked and the lag between them. The lags increased with the adoption of efficient irrigation practices and higher recharge rates. Results indicate that, in Texas, withdrawals peaked in 1966, followed by a peak in grain production 9 y later. After better irrigation technologies were adopted, the lag increased to 15 y from 1997 to 2012. In Kansas, where these technologies were employed concurrently with the rise of irrigated grain production, this lag was predicted to be 24 y starting in 1994. In Nebraska, grain production is projected to continue rising through 2050 because of high recharge rates. While Texas and Nebraska had equal irrigated output in 1975, by 2050, it is projected that Nebraska will have almost 10 times the groundwater-based production of Texas

    Does clinical examination aid in the diagnosis of urinary tract infections in women? A systematic review and meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Clinicians should be aware of the diagnostic values of various symptoms, signs and antecedents. This information is particularly important in primary care settings, where sophisticated diagnostic approaches are not always feasible. The aim of the study is to determine the probability that various symptoms, signs, antecedents and tests predict urinary tract infection (UTI) in women.</p> <p>Methods</p> <p>We conducted a systematic search of the MEDLINE and EMBASE databases to identify articles published in all languages through until December 2008. We particularly focused on studies that examined the diagnostic accuracy of at least one symptom, sign or patient antecedent related to the urinary tract. We included studies where urine culture, a gold standard, was preformed by primary care providers on female subjects aged at least 14 years. A meta-analysis of the likelihood ratio was performed to assess variables related to the urinary tract symptoms.</p> <p>Results</p> <p>Of the 1, 212 articles identified, 11 met the selection criteria. Dysuria, urgency, nocturia, sexual activity and urgency with dysuria were weak predictors of urinary tract infection, whereas increases in vaginal discharge and suprapubic pain were weak predictors of the absence of infection. Nitrites or leukocytes in the dipstick test are the only findings that clearly favored a diagnosis of UTI.</p> <p>Conclusions</p> <p>Clinical findings do not aid in the diagnosis of UTI among women who present with urinary symptoms. Vaginal discharge is a weak indicator of the absence of infection. The urine dipstick test was the most reliable tool for detecting UTI.</p

    Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences

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    The Lamb shift in muonic hydrogen 1

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    Abstract: The long quest for a measurement of the Lamb shift in muonic hydrogen is over. Last year we measured the energy splitting (Pohl et al., Nature, 466, 213 (2010)) in mp with an experimental accuracy of 15 ppm, twice better than our proposed goal. Using current QED calculations of the fine, hyperfine, QED, and finite size contributions, we obtain a rootmean-square proton charge radius of r p = 0.841 84 (67) fm. This value is 10 times more precise, but 5 standard deviations smaller, than the 2006 CODATA value of r p . The origin of this discrepancy is not known. Our measurement, together with precise measurements of the 1S-2S transition in regular hydrogen and deuterium, gives improved values of the Rydberg constant, R ? = 10 973 731.568 16
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