5,577 research outputs found

    Multidisciplinary research in the space sciences

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    Research activities were carried out in the following areas during this reporting period: (1) astrophysics; (2) climate and atmospheric modeling; and (3) climate applications of earth observations & geological studies. An ultra-low-noise 115 GHz receiver based upon a superconducting tunnel diode mixer has been designed and constructed. The first laboratory tests have yielded spectacular results: a single-sideband noise temperature of 75 K considerably more sensitive than any other receiver at this frequency. The receiver will replace that currently in use on the Columbia-GISS CO Sky Survey telescope. The 1.2 meter millimeter-wave telescope at Columbia University has been used to complete two large-scale surveys of molecular matter in the part of the inner galaxy which is visible from the Northern hemisphere (the first galactic quadrant); one of the distant galaxy and one of the solar neighborhood. The research conducted during the past year in the climate and atmospheric modeling programs has been focused on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Principal models are a one-dimensional radiative-convective model, a three-dimensional global climate model, and an upper ocean model. During the past year this project has focused on development of 2-channel satellite analysis methods and radiative transfer studies in support of multichannel analysis techniques

    A study of trace contaminant identification by microwave double resonance spectroscopy

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    Trace contaminant identification using microwave double resonance spectroscop

    Pars plana vitrectomy for primary rhegmatogenous retinal detachment

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    Pars plana vitrectomy (PPV) is growing in popularity for the treatment of primary rhegmatogenous retinal detachment (RD). PPV achieves favorable anatomic and visual outcomes in a wide variety of patients, especially in pseudophakic RD. A growing number of clinical series, both retrospective and prospective, have demonstrated generally comparable outcomes comparing PPV and scleral buckling (SB) under a variety of circumstances. The Scleral Buckling Versus Primary Vitrectomy in Rhegmatogenous Retinal Detachment (SPR) study is a multicenter, randomized, prospective, controlled clinical trial comparing SB versus PPV. This study should provide useful guidelines in the future. At this time, the choice of SB versus PPV should be based on the characteristics of the RD, the patient as a whole, and the experience and preference of the individual retinal surgeon

    Pharmacotherapies for Diabetic Retinopathy: Present and Future

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    Diabetic retinopathy remains a major cause of worldwide preventable blindness. Measures to avoid blindness include medical management (control of blood sugar, blood pressure, and serum lipids) and ocular management (laser photocoagulation and pars plana vitrectomy). Adjunctive pharmacologic therapies (intravitreal triamcinolone acetonide and anti-vascular endothelial growth factor agents) have shown early promise in the treatment of both diabetic macular edema and proliferative diabetic retinopathy. Other medications under investigation include the fluocinolone acetonide implantable device, extended-release dexamethasone implant, oral ruboxistaurin, and intravitreal hyaluronidase

    Vibrational relaxation measurements in CO2 USING an induced fluorescence technique

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    Vibrational relaxation measurements in carbon dioxide using induced infrared fluorescence techniqu

    Emerging Pharmacotherapies for Diabetic Macular Edema

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    Diabetic macular edema (DME) remains an important cause of visual loss in patients with diabetes mellitus. Although photocoagulation and intensive control of systemic metabolic factors have been reported to achieve improved outcomes in large randomized clinical trials (RCTs), some patients with DME continue to lose vision despite treatment. Pharmacotherapies for DME include locally and systemically administered agents. We review several agents that have been studied for the treatment of DME

    Ultrafast control of inelastic tunneling in a double semiconductor quantum

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    In a semiconductor-based double quantum well (QW) coupled to a degree of freedom with an internal dynamics, we demonstrate that the electronic motion is controllable within femtoseconds by applying appropriately shaped electromagnetic pulses. In particular, we consider a pulse-driven AlxGa1-xAs based symmetric double QW coupled to uniformly distributed or localized vibrational modes and present analytical results for the lowest two levels. These predictions are assessed and generalized by full-fledged numerical simulations showing that localization and time-stabilization of the driven electron dynamics is indeed possible under the conditions identified here, even with a simultaneous excitations of vibrational modes.Comment: to be published in Appl.Phys.Let

    Endophthalmitis: state of the art

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    Endophthalmitis is an uncommon diagnosis but can have devastating visual outcomes. Endophthalmitis may be endogenous or exogenous. Exogenous endophthalmitis is caused by introduction of pathogens through mechanisms such as ocular surgery, open-globe trauma, and intravitreal injections. Endogenous endophthalmitis occurs as a result of hematogenous spread of bacteria or fungi into the eye. These categories of endophthalmitis have different risk factors and causative pathogens, and thus require different diagnostic, prevention, and treatment strategies. Novel diagnostic techniques such as real-time polymerase chain reaction (RT-PCR) have been reported to provide improved diagnostic results over traditional culture techniques and may have a more expanded role in the future. While the role of povidone-iodine in prophylaxis of postoperative endophthalmitis is established, there remains controversy with regard to the effectiveness of other measures, including prophylactic antibiotics. The Endophthalmitis Vitrectomy Study (EVS) has provided us with valuable treatment guidelines. However, these guidelines cannot be directly applied to all categories of endophthalmitis, highlighting the need for continued research into attaining improved treatment outcomes
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