2,382 research outputs found

    The Alternative Appeal

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    For decades, Americans expressed dissatisfaction with conventional cancer treatments. I examine the appeal of biological alternatives to surgery, chemotherapy, and radiation therapy for patients with cancer. The limited effectiveness and side effects of many conventional cancer therapies led many patients to pursue a variety of unconventional therapies. To improve the quality of care for cancer patients, mainstream providers must better understand, and even collaborate with, alternative practitioners

    The Alternative Appeal

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    For decades, Americans expressed dissatisfaction with conventional cancer treatments. I examine the appeal of biological alternatives to surgery, chemotherapy, and radiation therapy for patients with cancer. The limited effectiveness and side effects of many conventional cancer therapies led many patients to pursue a variety of unconventional therapies. To improve the quality of care for cancer patients, mainstream providers must better understand, and even collaborate with, alternative practitioners

    On the Detection of Molecules in the Atmosphere of HD189733b using HST NICMOS Transmission Spectroscopy

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    The HST/NICMOS transmission spectrum measurements of HD 189733b that suggest the detection of methane (CH4_{4}) in an exoplanet atmosphere have been a source of significant controversy. With what is probably the best analyzed exoplanet spectroscopy data set to date, different teams, using different methods, have claimed evidence both contradicting and supporting the original findings. Here, we report results from a uniform spectral retrieval analysis of the three, independent, published spectra together with null hypothesis testing. Based on Bayesian model comparison, we find that two of the three spectra show strong evidence (\geq 3.6σ\sigma) for the detection of molecular features mainly due to water and methane while the third is consistent with a weak molecular detection at the 2.2σ\sigma level. We interpret the agreement in the spectral modulation established by previous authors and the atmospheric retrieval results presented here, as a confirmation of the original detection of molecular absorbers in the atmosphere of HD 189733b.Comment: Accepted to Ap

    A study of the community schools concept : the Fort Rouge experiment

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    108 leaves : ill. ; 28 c

    Probing the terminator region atmosphere of the Hot-Jupiter XO-1b with transmission spectroscopy

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    We report here the first infrared spectrum of the hot-Jupiter XO-1b. The observations were obtained with NICMOS instrument onboard the Hubble Space Telescope during a primary eclipse of the XO-1 system. Near photon-noise-limited spectroscopy between 1.2 and 1.8 micron allows us to determine the main composition of this hot-Jupiter's planetary atmosphere with good precision. This is the third hot-Jupiter's atmosphere for which spectroscopic data are available in the near IR. The spectrum shows the presence of water vapor (H2O), methane (CH4) and carbon dioxide (CO2), and suggests the possible presence of carbon monoxide (CO). We show that the published IRAC secondary transit emission photometric data are compatible with the atmospheric composition at the terminator determined from the NICMOS spectrum, with a range of possible mixing-ratios and thermal profiles; additional emission spectroscopy data are needed to reduce the degeneracy of the possible solutions. Finally, we note the similarity between the 1.2-1.8 micron transmission spectra of XO-1b and HD 209458b, suggesting that in addition to having similar stellar/orbital and planetary parameters the two systems may also have a similar exoplanetary atmospheric composition.Comment: ApJ accepted, 4 figure

    Blind extraction of an exoplanetary spectrum through Independent Component Analysis

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    Blind-source separation techniques are used to extract the transmission spectrum of the hot-Jupiter HD189733b recorded by the Hubble/NICMOS instrument. Such a 'blind' analysis of the data is based on the concept of independent component analysis. The de-trending of Hubble/NICMOS data using the sole assumption that nongaussian systematic noise is statistically independent from the desired light-curve signals is presented. By not assuming any prior, nor auxiliary information but the data themselves, it is shown that spectroscopic errors only about 10 - 30% larger than parametric methods can be obtained for 11 spectral bins with bin sizes of ~0.09 microns. This represents a reasonable trade-off between a higher degree of objectivity for the non-parametric methods and smaller standard errors for the parametric de-trending. Results are discussed in the light of previous analyses published in the literature. The fact that three very different analysis techniques yield comparable spectra is a strong indication of the stability of these results.Comment: ApJ accepte

    Molecular Signatures in the Near Infrared Dayside Spectrum of HD 189733b

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    We have measured the dayside spectrum of HD 189733b between 1.5 and 2.5 microns using the NICMOS instrument on the Hubble Space Telescope. The emergent spectrum contains significant modulation, which we attribute to the presence of molecular bands seen in absorption. We find that water (H2O), carbon monoxide (CO), and carbon dioxide (CO2) are needed to explain the observations, and we are able to estimate the mixing ratios for these molecules. We also find temperature decreases with altitude in the ~0.01 < P < ~1 bar region of the dayside near-infrared photosphere and set an upper limit to the dayside abundance of methane (CH4) at these pressures.Comment: 13 pages, 3 figures. accepted in Astrophysical Journal Letter

    A market analysis and feasibility study for EMBLA Ltd.-Renovators

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    Report : 1 v. : ill

    Review of “Jacques Derrida: Opening Lines”

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