2,676 research outputs found
NASA aviation safety reporting system
The origins and development of the NASA Aviation Safety Reporting System (ASRS) are briefly reviewed. The results of the first quarter's activity are summarized and discussed. Examples are given of bulletins describing potential air safety hazards, and the disposition of these bulletins. During the first quarter of operation, the ASRS received 1464 reports; 1407 provided data relevant to air safety. All reports are being processed for entry into the ASRS data base. During the reporting period, 130 alert bulletins describing possible problems in the aviation system were generated and disseminated. Responses were received from FAA and others regarding 108 of the alert bulletins. Action was being taken with respect to 70 of the 108 responses received. Further studies are planned of a number of areas, including human factors problems related to automation of the ground and airborne portions of the national aviation system
The Effect of γ-Guanidinobutyric Acid on the Clotting Time of Normal Plasma and on the Euglobulin Lysis Time of Fibrinolytically Active Plasma
It has been established that ε-aminocaproic acid (EACA) inhibits the activation of human plasminogen (Ablondi et al., 1959; Alkjaersig, Fletcher, and Sherry, 1959). Because of this observation, this compound has been used extensively to inhibit the pathologically occurring fibrinolytic system in patients. Recently Roberts (1965) reported that another compound, γ-guanidinobutyric acid (GGBA), like EACA, inhibits the lysis of human blood clots. Furthermore, GGBA, unlike EACA, retards the formation of these clots. The present investigation was undertaken to determine whether GGBA inhibits clot formation in the one-stage prothrombin and in the partial thromboplastin time tests. In addition, the ability of GGBA to inhibit clot lysis was tested using blood from a patient showing active fibrinolysis
UV Degradation of the Optical Properties of Acrylic for Neutrino and Dark Matter Experiments
UV-transmitting (UVT) acrylic is a commonly used light-propagating material
in neutrino and dark matter detectors as it has low intrinsic radioactivity and
exhibits low absorption in the detectors' light producing regions, from 350 nm
to 500 nm. Degradation of optical transmittance in this region lowers light
yields in the detector, which can affect energy reconstruction, resolution, and
experimental sensitivities. We examine transmittance loss as a result of short-
and long-term UV exposure for a variety of UVT acrylic samples from a number of
acrylic manufacturers. Significant degradation peaking at 343 nm was observed
in some UVT acrylics with as little as three hours of direct sunlight, while
others exhibited softer degradation peaking at 310 nm over many days of
exposure to sunlight. Based on their measured degradation results, safe time
limits for indoor and outdoor UV exposure of UVT acrylic are formulated.Comment: 13 pages, 6 figures, 3 tables; To be submitted to Journal of
Instrumentatio
Bolometric light curves and explosion parameters of 38 stripped-envelope core-collapse supernovae
Literature data are collated for 38 stripped-envelope core-collapse supernovae (SE SNe; i.e. SNe IIb, Ib, Ic and Ic-BL) that have good light curve coverage in more than one optical band. Using bolometric corrections derived in previous work, the bolometric light curve of each SN is recovered and template bolometric light curves provided. Peak light distributions and decay rates are investigated; SNe subtypes are not cleanly distinguished in this parameter space, although some grouping of types does occur and there is a suggestion of a Phillips-like relation for most SNe Ic-BL. The bolometric light curves are modelled with a simple analytical prescription and compared to results from more detailed modelling. Distributions of the explosion parameters shows the extreme nature of SNe Ic-BL in terms of their 56Ni mass and the kinetic energy, however ejected masses are similar to other subtypes. SNe Ib and Ic have very similar distributions of explosion parameters, indicating a similarity in progenitors. SNe~IIb are the most homogeneous subtype and have the lowest average values for 56Ni mass, ejected mass, and kinetic energy. Ejecta masses for each subtype and SE SNe as a whole are inconsistent with those expected from very massive stars. The majority of the ejecta mass distribution is well described by more moderately massive progenitors in binaries, indicating these are the dominant progenitor channel for SE SNe
Quality of survival: a new concept framework to assess the quality of prolonged life in cancer
Background: Improved cancer care means that more patients are surviving longer, but there is a need to examine how well patients survive. We conducted an exploratory analysis of a new conceptual framework termed ‘quality of survival’ (QoS) that delineates the quality of patients’ experience.
Methods: This project included an electronic database search to investigate the survivorship landscape and to create a visual QoS map and semi-structured interviews with patients (n = 35), clinicians (n = 40), and payers (n = 7) to support the QoS map. QoS was discussed in the context of two tumor types, metastatic non-small cell lung cancer and metastatic melanoma.
Results: Despite increased long-term survival, no specific definition of QoS exists. Patients reported many impacts that affect QoS, clinicians viewed QoS as relevant to treatment decisions, and payers felt it could help communicate different aspects relevant to the patient. Four interconnected QoS dimensions were developed (quality of life, survival, side effects, and economic impact), which vary in importance along the care continuum.
Conclusion: QoS is a patient-centric concept that could help decision-making and patient communication. The QoS map could provide a framework to monitor patient experience and help patients frame what treatment attribute is most important to them at any point in the cancer continuum
SUSY approach to Pauli Hamiltonians with an axial symmetry
A two-dimensional Pauli Hamiltonian describing the interaction of a neutral
spin-1/2 particle with a magnetic field having axial and second order
symmetries, is considered. After separation of variables, the one-dimensional
matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum
mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and
also to the Hamiltonian hierarchies generated by intertwining operators. The
spectrum is studied by means of the associated matrix shape-invariance. The
relation between the intertwining operators and the second order symmetries is
established and the full set of ladder operators that complete the dynamical
algebra is constructed.Comment: 18 pages, 3 figure
Superintegrability and higher order polynomial algebras II
In an earlier article, we presented a method to obtain integrals of motion
and polynomial algebras for a class of two-dimensional superintegrable systems
from creation and annihilation operators. We discuss the general case and
present its polynomial algebra. We will show how this polynomial algebra can be
directly realized as a deformed oscillator algebra. This particular algebraic
structure allows to find the unitary representations and the corresponding
energy spectrum. We apply this construction to a family of caged anisotropic
oscillators. The method can be used to generate new superintegrable systems
with higher order integrals. We obtain new superintegrable systems involving
the fourth Painleve transcendent and present their integrals of motion and
polynomial algebras.Comment: 11 page
An infinite family of superintegrable systems from higher order ladder operators and supersymmetry
We will discuss how we can obtain new quantum superintegrable Hamiltonians
allowing the separation of variables in Cartesian coordinates with higher order
integrals of motion from ladder operators. We will discuss also how higher
order supersymmetric quantum mechanics can be used to obtain systems with
higher order ladder operators and their polynomial Heisenberg algebra. We will
present a new family of superintegrable systems involving the fifth Painleve
transcendent which possess fourth order ladder operators constructed from
second order supersymmetric quantum mechanics. We present the polynomial
algebra of this family of superintegrable systems.Comment: 8 pages, presented at ICGTMP 28, accepted for j.conf.serie
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