1,344 research outputs found

    Introduction to SQL

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    This chapter provides a very brief introduction to the Structured Query Language (SQL) for getting information from relational databases. We make no pretense that this is a complete or comprehensive discussion of SQL. There are many aspects of the language the will be completely ignored in the presentation. The goal here is to provide enough background so that users understand the basic concepts involved in building and using relational databases. We also go through the steps involved in building a particular astronomical database used in some of the other presentations in this volume

    Ras/Raf-1/MAPK pathway mediates response to tamoxifen but not chemotherapy in breast cancer patients

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    <b>Purpose</b>: The expression and activation of the Ras/Raf-1/mitogen-activated protein kinase (MAPK) pathway plays an important role in the development and progression of cancer, and may influence response to treatments such as tamoxifen and chemotherapy. In this study we investigated whether the expression and activation of the key components of this pathway influenced clinical outcome, to test the hypothesis that activation of the MAPK pathway drives resistance to tamoxifen and chemotherapy in women with breast cancer. <b>Experimental Design</b>: Breast tumors from patients at the Glasgow Royal Infirmary and others treated within the BR9601 trial were analyzed for expression of the three Ras isoforms, total Raf-1, active and inactive forms of Raf-1 [pRaf(ser338) and pRaf(ser259), respectively], MAPK, and phospho-MAPK using an immunohistochemical approach. Analyses were done with respect to disease free-survival and overall survival. <b>Results</b>: Expression and activation of the Ras pathway was associated with loss of benefit from treatment with tamoxifen but not chemotherapy. Overexpression of pRaf(ser338) was associated with shortened disease-free and overall survival time in univariate analyses. Multivariate analysis suggested pRaf(ser338) was independent of known prognostic markers in predicting outcome following tamoxifen treatment (<i>P</i>=0.03). <b>Conclusion</b>: This study suggests that activation of the Ras pathway predicts for poor outcome on tamoxifen but not chemotherapy, and identifies pRaf(ser338) as a potential marker of resistance to estrogen receptor–targeted therapy. In addition, it suggests that expression of pRaf(ser338) could identify patients for whom tamoxifen alone is insufficient adjuvant systemic therapy, but for whom the addition of chemotherapy may be of benefit

    A Prediction of Observable Rotation in the ICM of Abell 3266

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    We present a numerical Hydro+N-body model of A3266 whose X-ray surface brightness, temperature distribution, and galaxy spatial and velocity distribution data are consistent with the A3266 data. The model is an old (~3 Gyr), off-axis merger having a mass ratio of ~2.5:1. The less massive subcluster in the model is moving on a trajectory from southwest to northeast passing on the western side of the dominant cluster while moving into the plane of the sky at ~45 degrees. Off-axis mergers such as this one are an effective mechanism for transferring angular momentum to the intracluster medium (ICM), making possible a large scale rotation of the ICM. We demonstrate here that the ICM rotation predicted by our fully 3-dimensional model of A3266 is observable with current technology. As an example, we present simulated observations assuming the capabilities of the high resolution X-ray spectrometer (XRS) which was to have flown on Astro-E.Comment: 9 pages, 7 postscript figures, Fig. 3 and 6 are color postscript, Accepted for publication in the Astrophysical Journa

    Chandra observation of the central galaxies in A1060 cluster of galaxies

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    Chandra observation of the central region of the A1060 cluster of galaxies resolved X-ray emission from two giant elliptical galaxies, NGC 3311 and NGC 3309. The emission from these galaxies consists of two components, namely the hot interstellar medium (ISM) and the low-mass X-ray binaries (LMXBs). We found the spatial extent of the ISM component was much smaller than that of stars for both galaxies, while the ratios of X-ray to optical blue-band luminosities were rather low but within the general scatter for elliptical galaxies. After subtracting the LMXB component, the ISM is shown to be in pressure balance with the intracluster medium of A1060 at the outer boundary of the ISM. These results imply that the hot gas supplied from stellar mass loss is confined by the external pressure of the intracluster medium, with the thermal conduction likely to be suppressed. The cD galaxy NGC 3311 does not exhibit the extended potential structure which is commonly seen in bright elliptical galaxies, and we discuss the possible evolution history of the very isothermal cluster A1060.Comment: 12 pages, 7 figures, Latex2e(emulateapj5), accepted in Ap

    Mapping the HealthPathways literature: a scoping review protocol

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    Objective: This scoping review will identify what literature exists on HealthPathways and make suggestions for the direction of future HealthPathways research. Background: HealthPathways is a free to access, password protected online tool containing practical, easy to use, localised clinical and referral information that is primarily aimed at GPs. HealthPathways originated in Canterbury, New Zealand in 2008. Since this time the program has spread and is being used in 50 health systems across New Zealand, Australia, and the United Kingdom (Streamliners, 2022a). Despite such large spread of the program there has been relatively little literature published on the utility, usefulness and cost-effectiveness of HealthPathways. This scoping review aims to identify and describe all current HealthPathways literature and make recommendations for the direction of future HealthPathways research. Methods: The Joanna Briggs Institute (JBI) methodology will be used to develop the scoping review. Databases included in the search include MEDLINE (PubMEd), Embase, CINAHL, Web of Science, Google Scholar, Emerald and Cochrane. The inclusion criteria are studies and grey literature on HealthPathways that are published in English, with no time limit. Grey literature will be identified through searching relevant credible organisations and websites. All results will be entered into Covidence to be assessed by two reviewers against a set tool. The PRISMA extension for scoping reviews will be used for reporting. Ethics approval is not required as only published information will be used. The research will be disseminated through publication in an open access peer reviewed journal. Conclusions: This protocol is published to make the process for the review transparent and replicable. The scoping review will highlight the extent of evidence that exists on HealthPathways and may provide direction for decision making and future research

    Time-Dependence of the Mass Accretion Rate in Cluster Cooling Flows

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    We analyze two time-dependent cluster cooling flow models in spherical symmetry. The first assumes that the intracluster gas resides in a static external potential, and includes the effects of optically thin radiative cooling and mass deposition. This corresponds to previous steady-state cooling flow models calculated by White & Sarazin (1987). Detailed agreement is found between steady-state models and time-dependent models at fixed times in the simulations. The mass accretion rate is found either to increase or remain nearly constant once flows reach a steady state. The time rate of change of the accretion rate is strongly sensitive to the value of the mass deposition parameter q, but only mildly sensitive to the ratio beta of gravitational binding energy to gas temperature. We show that previous scaling arguments presented by Bertschinger (1988) and White (1988) are valid only for mature cooling flows with weak mass deposition (q ~< 1). The second set of models includes the effects of a secularly deepening cluster potential and secondary infall of gas from the Hubble flow. We find that such heating effects do not prevent the flows from reaching a steady state within an initial central cooling time.Comment: 22 pages (AASTeX) with 16 EPS figures; accepted for publication in The Astrophysical Journa

    Physics of the Merging Clusters Cygnus A, A3667, and A2065

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    We present ASCA gas temperature maps of the nearby merging galaxy clusters Cygnus A, A3667, and A2065. Cygnus A appears to have a particularly simple merger geometry that allows an estimate of the subcluster collision velocity from the observed temperature variations. We estimate it to be ~2000 km/s. Interestingly, this is similar to the free-fall velocity that the two Cygnus A subclusters should have achieved at the observed separation, suggesting that merger has been effective in dissipating the kinetic energy of gas halos into thermal energy, without channeling its major fraction elsewhere (e.g., into turbulence). In A3667, we may be observing a spatial lag between the shock front seen in the X-ray image and the corresponding rise of the electron temperature. A lag of the order of hundreds of kiloparsecs is possible due to the combination of thermal conduction and a finite electron-ion equilibration time. Forthcoming better spatial resolution data will allow a direct measurement of these phenomena using such lags. A2065 has gas density peaks coincident with two central galaxies. A merger with the collision velocity estimated from the temperature map should have swept away such peaks if the subcluster total mass distributions had flat cores in the centers. The fact that the peaks have survived (or quickly reemerged) suggests that the gravitational potential also is strongly peaked. Finally, the observed specific entropy variations in A3667 and Cygnus A indicate that energy injection from a single major merger may be of the order of the full thermal energy of the gas. We hope that these order of magnitude estimates will encourage further work on hydrodynamic simulations, as well as more quantitative representation of the simulation results.Comment: Corrected the Cyg-A figure (errors shown were 1-sigma not 90%); text unchanged. ApJ in press. Latex, 5 pages, 3 figures (2 color), uses emulateapj.st

    Chandra Observation of the Cluster Environment of a WAT Radio Source in Abell 1446

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    Wide-angle tail (WAT) radio sources are often found in the centers of galaxy clusters where intracluster medium (ICM) ram pressure may bend the lobes into their characteristic C-shape. We examine the low redshift (z=0.1035) cluster Abell 1446, host to the WAT radio source 1159+583. The cluster exhibits possible evidence for a small-scale cluster-subcluster merger as a cause of the WAT radio source morphology. This evidence includes the presence of temperature and pressure substructure along the line that bisects the WAT as well as a possible wake of stripped interstellar material or a disrupted cool core to the southeast of the host galaxy. A filament to the north may represent cool, infalling gas that's contributing to the WAT bending while spectroscopically determined redshifts of member galaxies may indicate some component of a merger occurring along the line-of-sight. The WAT model of high flow velocity and low lobe density is examined as another scenario for the bending of 1159+583. It has been argued that such a model would allow the ram pressure due to the galaxy's slow motion through the ICM to shape the WAT source. A temperature profile shows that the cluster is isothermal (kT= 4.0 keV) in a series of annuli reaching a radius of 400 kpc. There is no evidence of an ongoing cooling flow. Temperature, abundance, pressure, density, and mass profiles, as well as two-dimensional maps of temperature and pressure are presented.Comment: 40 AASTeX pages including 15 postscript figures; accepted for publication in Ap

    Effect of high temperature VPT conditions on the development of aligned ZnO nanorod arrays grown by a three step catalyst-free method

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    Using Transmission Electron Microscopy-related techniques, we study the effect of the high temperature in the Vapour Phase Transport (VPT) process on the morphology and chemistry of VPT ZnO nanorod arrays deposited on a two-step Chemical Bath Deposition (CBD) buffer layers on silicon substrates. Though well-aligned and c-axis oriented arrays of ZnO nanorods are achieved, we have noticed the strong dependence of the nanorod morphology on the VPT growth conditions such as the temperature ramp rate and the placement of samples with respect to the metal source. The development of conical structures in the nanorod bases and the formation of a double intermediate layer below the base of nanorods are the main features found. The modifications of the ZnO nanostructures both in the base and in the underlying buffer layers due to the high VPT temperatures are also examined in detail
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