6,535 research outputs found

    A Quasi-Global Presentation of TIROS III Radiation Data

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    The TIROS III meteorological satellite was equipped with a five-channel medium resolution radiometer to measure the reflected solar radiation as well as the infrared emission of the earth-atmosphere system in five different spectral regions (Reference 1). According to the initial design of this radiation experiment, one of the most useful applications of the infrared measurements was to be the derivation of day and nighttime cloudiness from Channel 2, which was sensitive within the atmospheric "window" region (8 to 12 microns). Several authors already have demonstrated and discussed the principal usefulness of these data for this particular purpose (References 2, 3, and 4). This present study was performed to investigate and demonstrate the utility of the TIROS radiation data for global synoptic analyses

    Performance Pressure and Resource Allocation in Washington

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    Based on interviews with state, district, and school officials, explores how performance pressures have changed resource allocation decisions. Examines reform goals and how Washington's finance system impedes efforts to link resources to student learning

    On-Chip Cavity Optomechanical Coupling

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    On-chip cavity optomechanics, in which strong co-localization of light and mechanical motion is engineered, relies on efficient coupling of light both into and out of the on-chip optical resonator. Here we detail our particular style of tapered and dimpled optical fibers, pioneered by the Painter group at Caltech, which are a versatile and reliable solution to efficient on-chip coupling. First, a brief overview of tapered, single mode fibers is presented, in which the single mode cutoff diameter is highlighted. The apparatus used to create a dimpled tapered fiber is then described, followed by a comprehensive account of the procedure by which a dimpled tapered fiber is produced and mounted in our system. The custom-built optical access vacuum chambers in which our on-chip optomechanical measurements are performed are then discussed. Finally, the process by which our optomechanical devices are fabricated and the method by which we explore their optical and mechanical properties is explained. It is our expectation that this manuscript will enable the novice to develop advanced optomechanical experiments.Comment: 31 pages, 9 figure

    Thin n-i-p radiation-resistant solar cell feasibility study

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    Silicon solar cells were fabricated to verify the predictions that: (1) thin n(+)pp(+) cells can provide high values of open circuit voltage even when high resistivity base material ( 1000 omega-cm) is used; (2) cells with good p(+) back contacts will display an increase in open circuit voltage with decreasing cell thickness; and (3) high quality, thin, high resistivity, solar cells can be made using processing compatible with conventional practice. Analysis of I-V and spectral response measurements of these cells confirmed theoretical predictions and thereby pointed to voltages beyond the near 600 mV obtained in this study

    Further Correlations of Cell Metabolism and Resistance to Tuberculosis: Studies on Mononuclear Peritoneal Exudate Cells from Mice and Guinea Pigs

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    The metabolic activity of mononuclear exudate cells from mice of different strains, and from the guinea pig, have been compared to the rabbit with the aim of relating metabolic activity of these cells to resistance of these species to tuberculosis. The presence of mast cells in the peritoneal exudates of mice was thought to interfere with the dehydrogenation of certain substrates due to the release of histamine. Some experimental evidence presented by the authors seems to support this thesis

    Surgical management of metastatic disease to the adrenal gland

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    Metastatic disease to the adrenal glands can occur in a wide array of malignancies. With the increased use of abdominal imaging, these lesions are diagnosed with more frequency. Diagnostic and laboratory evaluation is essential for the differentiation of benign lesions from primary malignant adrenal tumors or extra-adrenal metastasis. Computed tomography (CT) and magnetic resonance imaging (MRI) characteristics, as well as the adjunctive use of immunocytochemical techniques on biopsy specimens, can allow accurate identification of metastatic lesions. Surgical management of metastastic lesions is appropriate in selected patients, primarily when representing the solitary site of metastatic disease. The surgical approach, while debatable, can de done either through open surgery or laparoscopically. Either approach appears comparable in terms of oncologic efficacy in the carefully selected patient, although laparoscopic adrenalectomy is associated with decreased pain and improved convalescence. The surgeon’s skill in laparoscopic technique, appropriate patient selection, and the ability to adhere to oncologic principles, including complete excision without tumor spillage, are of utmost importance when deciding the appropriate surgical intervention

    PKSB1740-517: An ALMA view of the cold gas feeding a distant interacting young radio galaxy

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    Cold neutral gas is a key ingredient for growing the stellar and central black hole mass in galaxies throughout cosmic history. We have used the Atacama Large Millimetre Array (ALMA) to detect a rare example of redshifted 12^{12}CO(2-1) absorption in PKS B1740-517, a young (t1.6×103t \sim 1.6 \times 10^{3} yr) and luminous (L5GHz6.6×1043L_{\rm 5 GHz} \sim 6.6 \times 10^{43} erg s1^{-1} ) radio galaxy at z=0.44z = 0.44 that is undergoing a tidal interaction with at least one lower-mass companion. The coincident HI 21-cm and molecular absorption have very similar line profiles and reveal a reservoir of cold gas (Mgas107108M_{\rm gas} \sim 10^{7} - 10^{8} M_{\odot}), likely distributed in a disc or ring within a few kiloparsecs of the nucleus. A separate HI component is kinematically distinct and has a very narrow line width (ΔvFWHM5\Delta{v}_{\rm FWHM} \lesssim 5 km s1^{-1}), consistent with a single diffuse cloud of cold (Tk100T_{\rm k} \sim 100 K) atomic gas. The 12^{12}CO(2-1) absorption is not associated with this component, which suggests that the cloud is either much smaller than 100 pc along our sight-line and/or located in low-metallicity gas that was possibly tidally stripped from the companion. We argue that the gas reservoir in PKS B1740-517 may have accreted onto the host galaxy \sim50 Myr before the young radio AGN was triggered, but has only recently reached the nucleus. This is consistent with the paradigm that powerful luminous radio galaxies are triggered by minor mergers and interactions with low-mass satellites and represent a brief, possibly recurrent, active phase in the life cycle of massive early type galaxies.Comment: 15 pages, 7 figures, accepted for publication in MNRA

    Radiative association and inverse predissociation of oxygen atoms

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    The formation of \mbox{O}_2 by radiative association and by inverse predissociation of ground state oxygen atoms is studied using quantum-mechanical methods. Cross sections, emission spectra, and rate coefficients are presented and compared with prior experimental and theoretical results. At temperatures below 1000~K radiative association occurs by approach along the 13Πu1\,{}^3\Pi_u state of \mbox{O}_2 and above 1000~K inverse predissociation through the \mbox{B}\,{}^3\Sigma_u^- state is the dominant mechanism. This conclusion is supported by a quantitative comparison between the calculations and data obtained from hot oxygen plasma spectroscopy.Comment: submitted to Phys. Rev. A (Sept. 7., 1994), 19 pages, 4 figures, latex (revtex3.0 and epsf.sty

    BNCI systems as a potential assistive technology: ethical issues and participatory research in the BrainAble project

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    This paper highlights aspects related to current research and thinking about ethical issues in relation to Brain Computer Interface (BCI) and Brain-Neuronal Computer Interfaces (BNCI) research through the experience of one particular project, BrainAble, which is exploring and developing the potential of these technologies to enable people with complex disabilities to control computers. It describes how ethical practice has been developed both within the multidisciplinary research team and with participants. Results: The paper presents findings in which participants shared their views of the project prototypes, of the potential of BCI/BNCI systems as an assistive technology, and of their other possible applications. This draws attention to the importance of ethical practice in projects where high expectations of technologies, and representations of “ideal types” of disabled users may reinforce stereotypes or drown out participant “voices”. Conclusions: Ethical frameworks for research and development in emergent areas such as BCI/BNCI systems should be based on broad notions of a “duty of care” while being sufficiently flexible that researchers can adapt project procedures according to participant needs. They need to be frequently revisited, not only in the light of experience, but also to ensure they reflect new research findings and ever more complex and powerful technologies
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