611 research outputs found

    Evaluating Flight Delay Benefits From The NextGen Program

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    This research proposes a method to simulate the flight delay effects of the NextGen program against an actual flight schedule. With the advent of the NextGen program and the substantial cost associated with the program, this research studies the impact the NextGen program may have on flight delays, an area critical to air carrier operations. This research is based on historical results from the summer of 2013 flight schedule to study the impact of a simulated NextGen implementation. The research studied aircraft on a given day looking specifically at the propagation effects of a flight delay and how it would change the total delay for a day. This study was conducted used a delay reduction distribution applied to historical flight delays attributed to the National Airspace System category. The research found a significant reduction in median flight delays per aircraft per day between the simulation results and historical delay. The delay reduction distribution was sampled to estimate the reduction for each segment in the flights for an aircraft\u27s day. Therefore, only reductions of delay or no changes to delay are possible in this study.

    Evidence for narrow resonant structures at W1.68W \approx 1.68 and W1.72W \approx 1.72 GeV in real Compton scattering off the proton

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    First measurement of the beam asymmetry Σ\Sigma for Compton scattering off the proton in the energy range Eγ=0.851.25E_{\gamma}=0.85 - 1.25 GeV is presented. The data reveals two narrow structures at Eγ=1.036E_{\gamma}= 1.036 and Eγ=1.119E_{\gamma}=1.119 GeV. They may signal narrow resonances with masses near 1.681.68 and 1.721.72 GeV, or they may be generated by the sub-threshold KΛK\Lambda and ωp\omega p production. Their decisive identification requires additional theoretical and experimental efforts.Comment: Published versio

    Evidence for Narrow N*(1685) Resonance in Quasifree Compton Scattering on the Neutron

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    The first study of quasi-free Compton scattering on the neutron in the energy range of Eγ=0.751.5E_{\gamma}=0.75 - 1.5 GeV is presented. The data reveals a narrow peak at W1.685W\sim 1.685 GeV. This result, being considered in conjunction with the recent evidence for a narrow structure at W1.68W\sim 1.68GeV in the η\eta photoproduction on the neutron, suggests the existence of a new nucleon resonance with unusual properties: the mass M1.685M\sim 1.685GeV, the narrow width Γ30\Gamma \leq 30MeV, and the much stronger photoexcitation on the neutron than on the proton.Comment: Replaced with the version published in Phys. Rev.

    The melanoma-specific graded prognostic assessment does not adequately discriminate prognosis in a modern population with brain metastases from malignant melanoma

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    The melanoma-specific graded prognostic assessment (msGPA) assigns patients with brain metastases from malignant melanoma to 1 of 4 prognostic groups. It was largely derived using clinical data from patients treated in the era that preceded the development of newer therapies such as BRAF, MEK and immune checkpoint inhibitors. Therefore, its current relevance to patients diagnosed with brain metastases from malignant melanoma is unclear. This study is an external validation of the msGPA in two temporally distinct British populations.Performance of the msGPA was assessed in Cohort I (1997-2008, n=231) and Cohort II (2008-2013, n=162) using Kaplan-Meier methods and Harrell's c-index of concordance. Cox regression was used to explore additional factors that may have prognostic relevance.The msGPA does not perform well as a prognostic score outside of the derivation cohort, with suboptimal statistical calibration and discrimination, particularly in those patients with an intermediate prognosis. Extra-cerebral metastases, leptomeningeal disease, age and potential use of novel targeted agents after brain metastases are diagnosed, should be incorporated into future prognostic models.An improved prognostic score is required to underpin high-quality randomised controlled trials in an area with a wide disparity in clinical care

    Eta photoproduction off the neutron at GRAAL: Evidence for a resonant structure at W=1.67 GeV

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    New (preliminary) data on eta photoproduction off the neutron are presented. These data reveal a resonant structure at W=1.67 GeV.Comment: 8 pages, 4 figures. Published in Proceedings of Workshop on the Physics of Excited Nucleons NSTAR2004, Grenoble, France, March 24 - 27, pg.19

    Eta photoproduction off the neutron at GRAAL

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    The gamma n -> eta n quasi-free cross section reveals a resonant structure at W ~ 1.675 GeV. This structure may be a manifestation of a baryon resonance. A priori its properties, the possibly narrow width and the strong photocoupling to the neutron, look surprising. This structure may also signal the existence of a narrow state.Comment: To appear in Proceedings of Workshop on the Physics of Excited Nucleons NSTAR2005, 12 - 15 October 2005, Tallahassee, Florida, US

    Derivation Of Functional Human Astrocytes From Cerebral Organoids

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Astrocytes play a critical role in the development and homeostasis of the central nervous system (CNS). Astrocyte dysfunction results in several neurological and degenerative diseases. However, a major challenge to our understanding of astrocyte physiology and pathology is the restriction of studies to animal models, human post-mortem brain tissues, or samples obtained from invasive surgical procedures. Here, we report a protocol to generate human functional astrocytes from cerebral organoids derived from human pluripotent stem cells. The cellular isolation of cerebral organoids yielded cells that were morphologically and functionally like astrocytes. Immunolabelling and proteomic assays revealed that human organoid-derived astrocytes express the main astrocytic molecular markers, including glutamate transporters, specific enzymes and cytoskeletal proteins. We found that organoid-derived astrocytes strongly supported neuronal survival and neurite outgrowth and responded to ATP through transient calcium wave elevations, which are hallmarks of astrocyte physiology. Additionally, these astrocytes presented similar functional pathways to those isolated from adult human cortex by surgical procedures. This is the first study to provide proteomic and functional analyses of astrocytes isolated from human cerebral organoids. The isolation of these astrocytes holds great potential for the investigation of developmental and evolutionary features of the human brain and provides a useful approach to drug screening and neurodegenerative disease modelling.7Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroFAPERJConselho Nacional para o Desenvolvimento Cientifico e TecnologicoCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel SuperiorCAPESFundacao de Amparo a Pesquisa do Estado de Sao PauloFAPESP [13/08711-3, 14/10068-4, 14/21035-0, 16/07332-7]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Eta photoproduction on the neutron at GRAAL: Measurement of the differential cross section

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    In this contribution, we will present our first preliminary measurement of the differential cross section for the reaction gamma+n->eta+n. Comparison of the reactions gamma+p->eta+p for free and bound proton (D2 target) will also be discussed.Comment: 6 pages, 4 figures, Proceedings of the 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, August 29-September 4 2004, Beijing, Chin
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