3,088 research outputs found

    Consideration of Abiotic Natural Resources in Life Cycle Assessments

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    The book contains a collection of articles dealing with how the extraction of mineral resources can be considered in environmental analyses such as Life Cycle Assessment (LCA). The consumption of resources, e.g., metals, is increasing strongly worldwide. This is associated with more energy use; environmental pollution; and social, economic, and political consequences. An increase is also expected for the coming decades. At the same time, modern products and technologies, even in the field of renewable energies, require a large number of critical raw materials. A crucial question here is the exhaustibility of natural resources. What is the relevance of resource depletion today? Must a geological shortage of metals be expected in the foreseeable future? How could such a thing be considered in the LCA of products and weighed against other environmental aspects? The articles in question have been written over the past three years by leading experts in both geology and environmental sciences and show the breadth of the controversial discussion

    Overview of the Tevatron Collider Complex: Goals, Operations and Performance

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    For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatron's operational history, and briefly describe operations of each accelerator in the chain and achieved performance.Comment: Includes modifications suggested by reviewer

    Magnetic Resonance Imaging-Based Assessment of Breast Cancer-Related Lymphoedema Tissue Composition.

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    OBJECTIVES: The aim of this study was to propose a magnetic resonance imaging acquisition and analysis protocol that uses image segmentation to measure and depict fluid, fat, and muscle volumes in breast cancer-related lymphoedema (BCRL). This study also aims to compare affected and control (unaffected) arms of patients with diagnosed BCRL, providing an analysis of both the volume and the distribution of the different tissue components. MATERIALS AND METHODS: The entire arm was imaged with a fluid-sensitive STIR and a 2-point 3-dimensional T1W gradient-echo-based Dixon sequences, acquired in sagittal orientation and covering the same imaging volume. An automated image postprocessing procedure was developed to simultaneously (1) contour the external volume of the arm and the muscle fascia, allowing separation of the epifacial and subfascial volumes; and to (2) separate the voxels belonging to the muscle, fat, and fluid components. The total, subfascial, epifascial, muscle (subfascial), fluid (epifascial), and fat (epifascial) volumes were measured in 13 patients with unilateral BCRL. Affected versus unaffected volumes were compared using a 2-tailed paired t test; a value of P < 0.05 was considered to be significant. Pearson correlation was used to investigate the linear relationship between fat and fluid excess volumes. The distribution of fluid, fat, and epifascial excess volumes (affected minus unaffected) along the arm was also evaluated using dedicated tissue composition maps. RESULTS: Total arm, epifascial, epifascial fluid, and epifascial fat volumes were significantly different (P < 0.0005), with greater volume in the affected arms. The increase in epifascial volume (globally, 94% of the excess volume) constituted the bulk of the lymphoedematous swelling, with fat comprising the main component. The total fat excess volume summed over all patients was 2.1 times that of fluid. Furthermore, fat and fluid excess volumes were linearly correlated (Pearson r = 0.75), with the fat excess volume being greater than the fluid in 11 subjects. Differences in muscle compartment volume between affected and unaffected arms were not statistically significant, and contributed only 6% to the total excess volume. Considering the distribution of the different tissue excess volumes, fluid accumulated prevalently around the elbow, with substantial involvement of the upper arm in only 3 cases. Fat excess volume was generally greater in the upper arm; however, the relative increase in epifascial volume, which considers the total swelling relative to the original size of the arm, was in 9 cases maximal within the forearm. CONCLUSIONS: Our measurements indicate that excess of fat within the epifascial layer was the main contributor to the swelling, even when a substantial accumulation of fluid was present. The proposed approach could be used to monitor how the internal components of BCRL evolve after presentation, to stratify patients for treatment, and to objectively assess treatment response. This methodology provides quantitative metrics not currently available during the standard clinical assessment of BCRL and shows potential for implementation in clinical practice

    Exile Vol. X No. 2

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    FICTION The Fragile Colour of Eyes by Susan Brady 6-17 The Trickster by Ed Brunner 19-26 On Passing by Sharon Haddock 32-42 POETRY Fishing with Light Tackle by Robert Hoyt 18 Poem by Sharon Haddock 27 On Insects by Robert Hoyt 28 A Chopper of Trees by Jerry Bryce 29 Nefertiti by Peggy Schmidt 31 The Gambler and the Corinthian by Robert Chester 42 Shades of Spring by Jane Cogie 43 GRAPHICS Monocut by Carol Kubie 5 Monocut by Parker Waite 18 Monocut by Doris Farrington 27 Watercolor by Kathy Koenig 31 Pen and Ink by Karen Gernenz 43 Awarded the semi-annual EXILE-Denison Bookstore Writing Prize: The Fragile Colour of Eyes by Susan Brady 6-17 Page numbers in the published table of contents are off by one. Page numbers given indicate where the works actually appear in the issue

    Exile Vol. XI No. 1

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    FICTION By the Fire of the Chief by Peggy Schmidt 9-17 From the Diary of a Vanishing Man by Ed Brunner 19-29 Dialogue by Ken Booth 35-37 POETRY Johnny Joe by Bill West 6-7 Caterpillar by Barb Bergantz 17 Poem by Bonnie McCarthy 29 The Queen by Hugh Wilder 31 The Clown by Barb Bergantz 32 Poem by Gretchen Schenck 33 Treatise on Cosmology by P. M. Grout 37 Stimulus by Susan Sherwood 37 Depot by Susan Sherwood 39 GRAPHICS Pen and Ink by Dave Goodwin 7 Pen and Ink by Ramona Gibbs 8 Pen and Ink by Tod Riddell 18 Charcoal by Dave Goodwin 30 Woodcut by Parker Waite III 34 Woodcut by Lela Giles 3

    Towards deterministic optical quantum computation with coherently driven atomic ensembles

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    Scalable and efficient quantum computation with photonic qubits requires (i) deterministic sources of single-photons, (ii) giant nonlinearities capable of entangling pairs of photons, and (iii) reliable single-photon detectors. In addition, an optical quantum computer would need a robust reversible photon storage devise. Here we discuss several related techniques, based on the coherent manipulation of atomic ensembles in the regime of electromagnetically induced transparency, that are capable of implementing all of the above prerequisites for deterministic optical quantum computation with single photons.Comment: 11 pages, 7 figure

    The Age of the Galactic Disk

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    I review different methods devised to derive the age of the Galactic Disk, namely the Radio-active Decay (RD), the Cool White Dwarf Luminosity Function (CWDLF), old opne clusters (OOC) and the Color Magnitude Diagram (CMD) of the stars in the solar vicinity. I argue that the disk is likely to be 8-10 Gyr old. Since the bulk of globulars has an age around 13 Gyr, the possibility emerges that the Galaxy experienced a minimum of Star Formation at the end of the halo/bulge formation. This minimum might reflect the time at which the Galaxy started to acquire material to form the disk inside-out.Comment: 10 pages, 4 figure, invited review, in "The chemical evolution of the Milky Way : Stars vs Clusters, Vulcano (Italy), 20-24 September 199

    The possible detection of a binary companion to a Type Ibn supernova progenitor

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    We present late-time observations of the site of the Type Ibn supernova (SN) 2006jc, acquired with the Hubble Space Telescope Advanced Camera for Surveys. A faint blue source is recovered at the SN position, with brightness mF W 435 = 26.76 0.20, mF W 555 = 26.60 0.23 and mF W 625 = 26.32 0.19 mag, although there is no detection in a contemporaneous narrow-band Ha image. The spectral energy distribution of the late-time source is well-fit by a stellar-like spectrum (log 3.7 Teff > and log L L > 4), subject to only a small degree of reddening —consistent with that estimated for SN 2006jc itself at early-times. The lack of further outbursts after the explosion of SN 2006jc suggests that the precursor outburst originated from the progenitor. The possibility of the source being a compact host cluster is ruled out on the basis of the source’s faintness; however, the possibility that the late-time source may be an unresolved light echo originating in a shell or sphere of pre-SN dust (within a radius 1 pc) is also discussed. Irrespective of the nature of the late-time source, these observations rule out a luminous blue variable as a companion to the progenitor of SN 2006jc
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