1,236 research outputs found

    The temperature dependence of inelastic light scattering from small particles for use in combustion diagnostic instrumentation

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    A computer calculation of the expected angular distribution of coherent anti-Stokes Raman scattering (CARS) from micrometer size polystyrene spheres based on a Mie-type model, and a pilot experiment to test the feasibility of measuring CARS angular distributions from micrometer size polystyrene spheres by simply suspending them in water are discussed. The computer calculations predict a very interesting structure in the angular distributions that depends strongly on the size and relative refractive index of the spheres

    Surveyor spacecraft system - Surveyor 6 flight performance Final report

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    Surveyor 6 spacecraft flight performance characteristics, including data on television equipment, alpha scattering experiment, and powered flight translatio

    A simplified instrument for recording strong motion earthquakes

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    A strong-motion earthquake recorder for the direct measurement of one point on the response spectrum curve is described, and results obtained with the instrument under field conditions are compared with those obtained by a standard spectrum analysis of accelerograph records. The device has the advantages of low initial cost and of low maintenance expense, and can thus be installed in relatively large numbers. A network of such instruments located at points having various local geological conditions is proposed as a supplement to the U. S. Coast and Geodetic Survey strong-motion seismograph system

    A General Framework for Complex Time-Driven Simulations on Hypercubes

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    We describe a general framework for building and running complex time-driven simulations with several levels of concurrency. The framework has been implemented on the Caltech/JPL Mark IIIfp hypercube using the Centaur communications protocol. Our framework allows the programmer to break the hypercube up into one or more subcubes of arbitrary size (task parallelism). Each subcube runs a separate application using data parallelism and synchronous communications internal to the subcube. Communications between subcubes are performed with asynchronous messages. Subcubes can each define their own parameters and commands which drive their particular application. These are collected and organized by the Control Processor (CP) in order that the entire simulation can be driven from a single command-driven shell. This system allows several programmers to develop disjoint pieces of a large simulation in parallel and to then integrate them with little effort. Each programmer is, of course, also able to take advantage of the separate data and I/O processors on each hypercube node in order to overlap calculation and communication (on-board parallelism) as well as the pipelined floating point processor on each node (pipelined processor parallelism). We show, as an example of the framework, a large space defense simulation. Functions (sensing, tracking, etc.) each comprise a subcube; functions are collected into defense platforms (satellites); and many platforms comprise the defense architecture. Software in the CP uses simple input to determine the node allocation to each function based on the desired defense architecture and number of platforms simulated in the hypercube. This allows many different architectures to be simulated. The set of simulated platforms, the results, and the messages between them are shown on color graphics displays. The methods used herein can be generalized to other simulations of a similar nature in a straightforward manner

    Athol D. Cloud to Dr. Silver, 1 March 1961

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    Personal correspondenc

    Tumor innate immunity primed by specific interferon-stimulated endogenous retroviruses.

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    Mesenchymal tumor subpopulations secrete pro-tumorigenic cytokines and promote treatment resistance1-4. This phenomenon has been implicated in chemorefractory small cell lung cancer and resistance to targeted therapies5-8, but remains incompletely defined. Here, we identify a subclass of endogenous retroviruses (ERVs) that engages innate immune signaling in these cells. Stimulated 3 prime antisense retroviral coding sequences (SPARCS) are oriented inversely in 3' untranslated regions of specific genes enriched for regulation by STAT1 and EZH2. Derepression of these loci results in double-stranded RNA generation following IFN-γ exposure due to bi-directional transcription from the STAT1-activated gene promoter and the 5' long terminal repeat of the antisense ERV. Engagement of MAVS and STING activates downstream TBK1, IRF3, and STAT1 signaling, sustaining a positive feedback loop. SPARCS induction in human tumors is tightly associated with major histocompatibility complex class 1 expression, mesenchymal markers, and downregulation of chromatin modifying enzymes, including EZH2. Analysis of cell lines with high inducible SPARCS expression reveals strong association with an AXL/MET-positive mesenchymal cell state. While SPARCS-high tumors are immune infiltrated, they also exhibit multiple features of an immune-suppressed microenviroment. Together, these data unveil a subclass of ERVs whose derepression triggers pathologic innate immune signaling in cancer, with important implications for cancer immunotherapy

    Assessment of digital image correlation measurement errors: methodology and results

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    Optical full-field measurement methods such as Digital Image Correlation (DIC) are increasingly used in the field of experimental mechanics, but they still suffer from a lack of information about their metrological performances. To assess the performance of DIC techniques and give some practical rules for users, a collaborative work has been carried out by the Workgroup “Metrology” of the French CNRS research network 2519 “MCIMS (Mesures de Champs et Identification en Mécanique des Solides / Full-field measurement and identification in solid mechanics, http://www.ifma.fr/lami/gdr2519)”. A methodology is proposed to assess the metrological performances of the image processing algorithms that constitute their main component, the knowledge of which being required for a global assessment of the whole measurement system. The study is based on displacement error assessment from synthetic speckle images. Series of synthetic reference and deformed images with random patterns have been generated, assuming a sinusoidal displacement field with various frequencies and amplitudes. Displacements are evaluated by several DIC packages based on various formulations and used in the French community. Evaluated displacements are compared with the exact imposed values and errors are statistically analyzed. Results show general trends rather independent of the implementations but strongly correlated with the assumptions of the underlying algorithms. Various error regimes are identified, for which the dependence of the uncertainty with the parameters of the algorithms, such as subset size, gray level interpolation or shape functions, is discussed

    Social identity, social networks and recovery capital in emerging adulthood: a pilot study

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    Background It has been argued that recovery from substance dependence relies on a change in identity, with past research focused on ‘personal identity’. This study assessed support for a social identity model of recovery in emerging adults through examining associations between social identity, social networks, recovery capital, and quality of life. Methods Twenty participants aged 18–21 in residential treatment for substance misuse were recruited from four specialist youth drug treatment services - three detoxification facilities and one psychosocial rehabilitation facility in Victoria, Australia. Participants completed a detailed social network interview exploring the substance use of groups in their social networks and measures of quality of life, recovery capital, and social identity. Results Lower group substance use was associated with higher recovery capital, stronger identification with non-using groups, and greater importance of non-using groups in the social network. Additionally, greater identification with and importance of non-using groups were associated with better environmental quality of life, whereas greater importance conferred on using groups was associated with reduced environmental quality of life. Conclusions Support was found for the role of social identity processes in reported recovery capital and quality of life. Future research in larger, longitudinal samples is required to improve understanding of social identity processes during treatment and early recovery and its relationship to recovery stability. Keywords Social network Social identity Emerging adult Substance use Treatment Recovery Quality of lif

    Abiotic formation of O2 and O3 in high-CO2 terrestrial atmospheres

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    Previous research has indicated that high amounts of ozone (O3) and oxygen (O2) may be produced abiotically in atmospheres with high concentrations of CO2. The abiotic production of these two gases, which are also characteristic of photosynthetic life processes, could pose a potential "false-positive" for remote-sensing detection of life on planets around other stars.We show here that such false positives are unlikely on any planet that possesses abundant liquid water, as rainout of oxidized species onto a reduced planetary surface should ensure that atmospheric H2 concentrations remain relatively high, and that O2 and O3 remain low. Our aim is to determine the amount of O3 and O2 formed in a high CO2 atmosphere for a habitable planet without life. We use a photochemical model that considers hydrogen (H2) escape and a detailed hydrogen balance to calculate the O2 and O3 formed on planets with 0.2 of CO2 around the Sun, and 0.02, 0.2 and 2 bars of CO2 around a young Sun-like star with higher UV radiation. The concentrations obtained by the photochemical model were used as input in a radiative transfer model that calculated the spectra of the modeled planets. The O3 and O2 concentrations in the simulated planets are extremely small, and unlikely to produce a detectable signature in the spectra of those planets. We conclude that with a balanced hydrogen budget, and for planets with an active hydrological cycle, abiotic formation of O2 and O3 is unlikely to create a possible false positive for life detection in either the visible/near-infrared or mid-infrared wavelength regimes.Comment: 27 pages, 15 figures, Astronomy & Astrophysics accepte

    The laurentian record of neoproterozoic glaciation, tectonism, and eukaryotic evolution in Death Vally, California

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    Neoproterozoic strata in Death Valley, California contain eukaryotic microfossils and glacial deposits that have been used to assess the severity of putative Snowball Earth events and the biological response to extreme environmental change. These successions also contain evidence for syn-sedimentary faulting that has been related to the rifting of Rodinia, and in turn the tectonic context of the onset of Snowball Earth. These interpretations hinge on local geological relationships and both regional and global stratigraphic correlations. Here we present new geological mapping, measured stratigraphic sections, carbon and strontium isotope chemostratigraphy, and micropaleontology from the Neoproterozoic glacial deposits and bounding strata in Death Valley. These new data enable us to refine regional correlations both across Death Valley and throughout Laurentia, and construct a new age model for glaciogenic strata and microfossil assemblages. Particularly, our remapping of the Kingston Peak Formation in the Saddle Peak Hills and near the type locality shows for the first time that glacial deposits of both the Marinoan and Sturtian glaciations can be distinguished in southeastern Death Valley, and that beds containing vase-shaped microfossils are slump blocks derived from the underlying strata. These slump blocks are associated with multiple overlapping unconformities that developed during syn-sedimentary faulting, which is a common feature of Cyrogenian strata along the margin of Laurentia from California to Alaska. With these data, we conclude that all of the microfossils that have been described to date in Neoproterozoic strata of Death Valley predate the glaciations and do not bear on the severity, extent or duration of Neoproterozoic Snowball Earth events
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