293 research outputs found

    Towards Automatic Blotch Detection for Film Restoration by Comparison of Spatio-Temporal Neighbours

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    In this paper, a new method of blotch detection for digitised film sequences is proposed. Due to the aging of film stocks, their poor storage and/or repeated viewing, it is estimated that approximately 50% of all films produced prior to 1950 have either been destroyed or rendered unwatchable [1,2]. To prevent their complete destruction, original film reels must be scanned into digital format; however, any defects such as blotches will be retained. By combining a variation of a linear time, contour tracing technique with a simple temporal nearest neighbour algorithm, a preliminary detection system has been created. Using component labelling of dirt and sparkle the overall performance of the completed system, in terms of time and accuracy, will compare favourably to traditional motion compensated detection methods. This small study (based on 13 film sequences) represents a significant first step towards automatic blotch detection

    Evolution of complex organic molecules in hot molecular cores: Synthetic spectra at (sub-)mm wavebands

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    Hot molecular cores (HMCs) are intermediate stages of high-mass star formation and are also known for their rich emission line spectra at (sub-)mm wavebands. The observed spectral feature of HMCs such as total number of emission lines and associated line intensities are also found to vary with evolutionary stages. We developed various 3D models for HMCs guided by the evolutionary scenarios proposed by recent empirical and modeling studies. We then investigated the spatio-temporal variation of temperature and molecular abundances in HMCs by consistently coupling gas-grain chemical evolution with radiative transfer calculations. We explored the effects of varying physical conditions on molecular abundances including density distribution and luminosity evolution of the central protostar(s). The time-dependent temperature structure of the hot core models provides a realistic framework for investigating the spatial variation of ice mantle evaporation as a function of evolutionary timescales. With increasing protostellar luminosity, the water ice evaporation font (∼\sim100K) expands and the spatial distribution of gas phase abundances of these COMs also spreads out. We simulated the synthetic spectra for these models at different evolutionary timescales to compare with observations. A qualitative comparison of the simulated and observed spectra suggests that these self-consistent hot core models can reproduce the notable trends in hot core spectral variation within the typical hot core timescales of 105^{5} year. These models predict that the spatial distribution of various emission line maps will also expand with evolutionary time. The model predictions can be compared with high resolution observation that can probe scales of a few thousand AU in high-mass star forming regions such as from ALMA.[Abridged]Comment: accepted for publication in A&

    Strategy and its discontents: the place of strategy in national policymaking

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    This paper presents a collection of views about the definition, role, purpose and health of strategic policymaking. Introduction One of the liveliest debates to have taken place on ASPI’s blog, The Strategist, concerned the place of strategy in Canberra’s policymaking community. It seems that there’s little consensus around what strategy’s core business should be, let alone who should practice it and whether indeed enough strategy is being done by DFAT, Defence or other parts of government. The 11 short pieces printed here by eight authors with quite diverse perspectives span a broad range of views about the definition, role, purpose and health of strategic policymaking. There’s no more important debate in public policy than on the place of strategy in meeting complex national challenges. This paper hopefully will encourage a more structured debate about strategy’s place at the heart of national policymaking

    Prevalence and geographical distribution of Papio hamadryas papillomavirus 1 (PhPV1) in Kenyan baboons

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    Papio hamadryas papillomavirus (PhPV) 1, 2, and 3, are Alphapapillomaviruses that have been detected in Kenyan Olive baboons but the distribution is unknown. Therefore, cervical screening for PhPV1 was performed in baboons from various areas in Kenya using a nested polymerase chain reaction. The prevalence rate was 33%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135993/1/jmp12247.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135993/2/jmp12247_am.pd

    Mapping Large-Scale CO Depletion in a Filamentary Infrared Dark Cloud

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    Infrared Dark Clouds (IRDCs) are cold, high mass surface density and high density structures, likely to be representative of the initial conditions for massive star and star cluster formation. CO emission from IRDCs has the potential to be useful for tracing their dynamics, but may be affected by depleted gas phase abundances due to freeze-out onto dust grains. Here we analyze C18O J=1-0 and J=2-1 emission line data, taken with the IRAM 30m telescope, of the highly filamentary IRDC G035.39.-0033. We derive the excitation temperature as a function of position and velocity, with typical values of ~7K, and thus derive total mass surface densities, Sigma_C18O, assuming standard gas phase abundances and accounting for optical depth in the line, which can reach values of ~1. The mass surface densities reach values of ~0.07 g/cm^2. We compare these results to the mass surface densities derived from mid-infrared (MIR) extinction mapping, Sigma_SMF, by Butler & Tan, which are expected to be insensitive to the dust temperatures in the cloud. With a significance of >10sigma, we find Sigma_C18O/Sigma_SMF decreases by about a factor of 5 as Sigma increases from ~0.02 to ~0.2 g/cm^2, which we interpret as evidence for CO depletion. Several hundred solar masses are being affected, making this one of the most massive clouds in which CO depletion has been observed directly. We present a map of the depletion factor in the filament and discuss implications for the formation of the IRDC.Comment: 9 pages, accepted to ApJ, Mac users: Figure 1 is best viewed with Adobe acroread rather than previe

    Broadband analysis techniques for Herschel/HIFI spectral surveys of chemically rich star-forming regions

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    The Heterodyne Instrument for the Far Infrared (HIFI) aboard the Herschel Space Observatory has acquired high-resolution broadband molecular spectra of star-forming regions in a wavelength range that is mostly inaccessible from ground-based astronomical observatories. These spectral surveys provide new insight into the chemical composition and physical properties of molecular clouds. In this manuscript, we present initial results from the HIFI spectral survey of the Sagittarius B2(N) molecular cloud, which contains spectral features assigned to at least 40 different molecules in a range of physical environments. While extensive line blending is observed due to the chemical complexity of this region, reliable molecular line identifications can be made, down to the noise floor, due to the large number of transitions detected for each species in the 1.2 THz survey bandwidth. This allows for the extraction of new weakly emitting species from the line forest. These HIFI surveys will be an invaluable archival resource for future investigations into interstellar chemistry.Comment: 14 pages, 2 figures; accepted to the Journal of Molecular Spectroscop

    A role for human brain pericytes in neuroinflammation

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    BACKGROUND: Brain inflammation plays a key role in neurological disease. Although much research has been conducted investigating inflammatory events in animal models, potential differences in human brain versus rodent models makes it imperative that we also study these phenomena in human cells and tissue. METHODS: Primary human brain cell cultures were generated from biopsy tissue of patients undergoing surgery for drug-resistant epilepsy. Cells were treated with pro-inflammatory compounds IFNγ, TNFα, IL-1β, and LPS, and chemokines IP-10 and MCP-1 were measured by immunocytochemistry, western blot, and qRT-PCR. Microarray analysis was also performed on late passage cultures treated with vehicle or IFNγ and IL-1β. RESULTS: Early passage human brain cell cultures were a mixture of microglia, astrocytes, fibroblasts and pericytes. Later passage cultures contained proliferating fibroblasts and pericytes only. Under basal culture conditions all cell types showed cytoplasmic NFκB indicating that they were in a non-activated state. Expression of IP-10 and MCP-1 were significantly increased in response to pro-inflammatory stimuli. The two chemokines were expressed in mixed cultures as well as cultures of fibroblasts and pericytes only. The expression of IP-10 and MCP-1 were regulated at the mRNA and protein level, and both were secreted into cell culture media. NFκB nuclear translocation was also detected in response to pro-inflammatory cues (except IFNγ) in all cell types. Microarray analysis of brain pericytes also revealed widespread changes in gene expression in response to the combination of IFNγ and IL-1β treatment including interleukins, chemokines, cellular adhesion molecules and much more. CONCLUSIONS: Adult human brain cells are sensitive to cytokine challenge. As expected 'classical' brain immune cells, such as microglia and astrocytes, responded to cytokine challenge but of even more interest, brain pericytes also responded to such challenge with a rich repertoire of gene expression. Immune activation of brain pericytes may play an important role in communicating inflammatory signals to and within the brain interior and may also be involved in blood brain barrier (BBB) disruption . Targeting brain pericytes, as well as microglia and astrocytes, may provide novel opportunities for reducing brain inflammation and maintaining BBB function and brain homeostasis in human brain disease

    Detection of extragalactic argonium, ArH+, toward PKS 1830−211

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    Context. Argonium has recently been detected as a ubiquitous molecule in our Galaxy. Model calculations indicate that its abundance peaks at molecular fractions in the range of 10^(-4) to 10^(-3) and that the observed column densities require high values of the cosmic ray ionization rate. Therefore, this molecular cation may serve as an excellent tracer of the very diffuse interstellar medium (ISM), as well as an indicator of the cosmic ray ionization rate. Aims. We attempted to detect ArH+ in extragalactic sources to evaluate its diagnostic power as a tracer of the almost purely atomic ISM in distant galaxies. Methods. We obtained ALMA observations of a foreground galaxy at z = 0.89 in the direction of the lensed blazar PKS 1830−211. Results. Two isotopologs of argonium, ^(36)ArH+ and ^(38)ArH+, were detected in absorption along two different lines of sight toward PKS 1830−211, known as the SW and NE images of the background blazar. The argonium absorption is clearly enhanced on the more diffuse line of sight (NE) compared to other molecular species. The isotopic ratio ^(36)Ar/^(38)Ar is 3.46 ± 0.16 toward the SW image, i.e., significantly lower than the solar value of 5.5. Conclusions. Our results demonstrate the suitability of argonium as a tracer of the almost purely atomic, diffuse ISM in high-redshift sources. The evolution of the isotopic ratio with redshift may help to constrain nucleosynthetic scenarios in the early Universe
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