185 research outputs found

    Field Localization and Enhancement of Phase Locked Second and Third Harmonic Generation in Absorbing Semiconductor Cavities

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    We predict and experimentally observe the enhancement by three orders of magnitude of phase mismatched second and third harmonic generation in a GaAs cavity at 650nm and 433nm, respectively, well above the absorption edge. Phase locking between the pump and the harmonics changes the effective dispersion of the medium and inhibits absorption. Despite hostile conditions the harmonics become localized inside the cavity leading to relatively large conversion efficiencies. Field localization plays a pivotal role and ushers in a new class of semiconductor-based devices in the visible and UV ranges

    Axial Vector JPC=1++J^{PC}=1^{++} Charmonium and Bottomonium Hybrid Mass Predictions with QCD Sum-Rules

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    Axial vector (JPC=1++)(J^{PC}=1^{++}) charmonium and bottomonium hybrid masses are determined via QCD Laplace sum-rules. Previous sum-rule studies in this channel did not incorporate the dimension-six gluon condensate, which has been shown to be important for 11^{--} and 0+0^{-+} heavy quark hybrids. An updated analysis of axial vector charmonium and bottomonium hybrids is presented, including the effects of the dimension-six gluon condensate. The axial vector charmonium and bottomonium hybrid masses are predicted to be 5.13 GeV and 11.32 GeV, respectively. We discuss the implications of this result for the charmonium-like XYZ states and the charmonium hybrid multiplet structure observed in recent lattice calculations.Comment: 10 pages, 7 figures. Updated to match published versio

    Ultrastructural, cytogenetic, and molecular findings in mast cell leukemia : Case report

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    We report a de novo aleukemic form of MCL with a complex monosomic karyotype with LOH for multiple chromosomes and TP53 mutation. Additionally, whereas D816V KIT was not found, the c-Kit transmembrane domain p.M541L variant was detected which is the most common SNP of KIT gene in humans with controversial pathogenic role. In these cases, it is crucial to perform a rapid broad molecular study for an accurate diagnosis which could help to initiate targeted therapy

    Salvage carbon dioxide transoral laser microsurgery for laryngeal cancer after (chemo)radiotherapy: a European Laryngological Society consensus statement

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    Purpose: To provide expert opinion and consensus on salvage carbon dioxide transoral laser microsurgery (CO2 TOLMS) for recurrent laryngeal squamous cell carcinoma (LSCC) after (chemo)radiotherapy [(C)RT]. Methods: Expert members of the European Laryngological Society (ELS) Cancer and Dysplasia Committee were selected to create a dedicated panel on salvage CO2 TOLMS for LSCC. A series of statements regarding the critical aspects of decision-making were drafted, circulated, and modified or excluded in accordance with the Delphi process. Results: The expert panel reached full consensus on 19 statements through a total of three sequential evaluation rounds. These statements were focused on different aspects of salvage CO2 TOLMS, with particular attention on preoperative diagnostic work-up, treatment indications, postoperative management, complications, functional outcomes, and follow-up. Conclusion: Management of recurrent LSCC after (C)RT is challenging and is based on the need to find a balance between oncologic and functional outcomes. Salvage CO2 TOLMS is a minimally invasive approach that can be applied to selected patients with strict and careful indications. Herein, a series of statements based on an ELS expert consensus aimed at guiding the main aspects of CO2 TOLMS for LSCC in the salvage setting is presented

    Dynamics of coherently pumped lasers with linearly polarized pump and generated fields

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    The influence of light polarization on the dynamics of an optically pumped single-mode laser with a homogeneously broadened four-level medium is theoretically investigated in detail. Pump and laser fields with either parallel or crossed linear polarizations are considered, as are typical in far-infrared-laser experiments. Numerical simulations reveal dramatically different dynamic behaviors for these two polarization configurations. The analysis of the model equations allows us to find the physical origin of both behaviors. In particular, the crossed-polarization configuration is shown to be effective in decoupling the pump and laser fields, thus allowing for the appearance of Lorenz-type dynamics

    GNSS transpolar earth reflectometry exploriNg system (G-TERN): Mission concept

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    The global navigation satellite system (GNSS) Transpolar Earth Reflectometry exploriNg system (G-TERN) was proposed in response to ESA's Earth Explorer 9 revised call by a team of 33 multi-disciplinary scientists. The primary objective of the mission is to quantify at high spatio-temporal resolution crucial characteristics, processes and interactions between sea ice, and other Earth system components in order to advance the understanding and prediction of climate change and its impacts on the environment and society. The objective is articulated through three key questions. 1) In a rapidly changing Arctic regime and under the resilient Antarctic sea ice trend, how will highly dynamic forcings and couplings between the various components of the ocean, atmosphere, and cryosphere modify or influence the processes governing the characteristics of the sea ice cover (ice production, growth, deformation, and melt)? 2) What are the impacts of extreme events and feedback mechanisms on sea ice evolution? 3) What are the effects of the cryosphere behaviors, either rapidly changing or resiliently stable, on the global oceanic and atmospheric circulation and mid-latitude extreme events? To contribute answering these questions, G-TERN will measure key parameters of the sea ice, the oceans, and the atmosphere with frequent and dense coverage over polar areas, becoming a "dynamic mapper" of the ice conditions, the ice production, and the loss in multiple time and space scales, and surrounding environment. Over polar areas, the G-TERN will measure sea ice surface elevation (<10 cm precision), roughness, and polarimetry aspects at 30-km resolution and 3-days full coverage. G-TERN will implement the interferometric GNSS reflectometry concept, from a single satellite in near-polar orbit with capability for 12 simultaneous observations. Unlike currently orbiting GNSS reflectometry missions, the G-TERN uses the full GNSS available bandwidth to improve its ranging measurements. The lifetime would be 2025-2030 or optimally 2025-2035, covering key stages of the transition toward a nearly ice-free Arctic Ocean in summer. This paper describes the mission objectives, it reviews its measurement techniques, summarizes the suggested implementation, and finally, it estimates the expected performance

    Electromagnetically induced transparency with a standing-wave drive in the frequency up-conversion regime

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    We study electromagnetically induced transparency for a probe traveling-wave (TW) laser field in closed Doppler-broadened three-level systems driven by a standing-wave (SW) laser field of moderate intensity (its Rabi frequencies are smaller than the Doppler width of the driven transition). We show that probe windows of transparency occur for values of the probe to drive field frequency ratio R close to half-integer values. For optical transitions and typical values of Doppler broadening for atoms in a vapor cell, we show that for R>1 a SW drive field is appreciably more efficient than a TW drive in inducing probe transparency. As examples, we consider parameters for real cascade schemes in barium atoms with R≈1.5 and in beryllium atoms with R≈3.5 showing that probe transmission values well above 50% are possible for conditions in which it is almost negligible either without driving field or with only one of the TW components of the drive. We show that a strongly asymmetric drive having two TW components with unequal intensities is even more eficient than a symmetric SW drive in inducing probe transparency. The case of arbitrary probe intensity is also considered

    Spatial Solitons and Anderson Localization

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    Stochastic (Anderson) localization is the spatial localization of the wave-function of quantum particles in random media. We show, that a corresponding phenomenon can stabilize spatial solitons in optical resonators: spatial solitons in resonators with randomly distorted mirrors are more stable than in perfect mirror resonators. We demonstrate the phenomenon numerically, by investigating solitons in lasers with saturable absorber, and analytically by deriving and analyzing coupled equations of spatially coherent and incoherent field components.Comment: submitted to Phys.Rev.

    Salvage carbon dioxide transoral laser microsurgery for laryngeal cancer after (chemo)radiotherapy: a European Laryngological Society consensus statement

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    Purpose To provide expert opinion and consensus on salvage carbon dioxide transoral laser microsurgery (CO2 TOLMS) for recurrent laryngeal squamous cell carcinoma (LSCC) after (chemo)radiotherapy [(C)RT].Methods Expert members of the European Laryngological Society (ELS) Cancer and Dysplasia Committee were selected to create a dedicated panel on salvage CO2 TOLMS for LSCC. A series of statements regarding the critical aspects of decision-making were drafted, circulated, and modified or excluded in accordance with the Delphi process.Results The expert panel reached full consensus on 19 statements through a total of three sequential evaluation rounds. These statements were focused on different aspects of salvage CO2 TOLMS, with particular attention on preoperative diagnostic work-up, treatment indications, postoperative management, complications, functional outcomes, and follow-up.Conclusion Management of recurrent LSCC after (C)RT is challenging and is based on the need to find a balance between oncologic and functional outcomes. Salvage CO2 TOLMS is a minimally invasive approach that can be applied to selected patients with strict and careful indications. Herein, a series of statements based on an ELS expert consensus aimed at guiding the main aspects of CO2 TOLMS for LSCC in the salvage setting is presented.Otorhinolaryngolog

    Transoral laser microsurgery for laryngeal cancer: A primer and review of laser dosimetry

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    Transoral laser microsurgery (TLM) is an emerging technique for the management of laryngeal and other head and neck malignancies. It is increasingly being used in place of traditional open surgery because of lower morbidity and improved organ preservation. Since the surgery is performed from the inside working outward as opposed to working from the outside in, there is less damage to the supporting structures that lie external to the tumor. Coupling the laser to a micromanipulator and a microscope allows precise tissue cutting and hemostasis; thereby improving visualization and precise ablation. The basic approach and principles of performing TLM, the devices currently in use, and the associated dosimetry parameters will be discussed. The benefits of using TLM over conventional surgery, common complications and the different settings used depending on the location of the tumor will also be discussed. Although the CO2 laser is the most versatile and the best-suited laser for TLM applications, a variety of lasers and different parameters are used in the treatment of laryngeal cancer. Improved instrumentation has lead to an increased utilization of TLM by head and neck cancer surgeons and has resulted in improved outcomes. Laser energy levels and spot size are adjusted to vary the precision of cutting and amount of hemostasis obtained
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