435 research outputs found

    The Dust and Molecular Gas in the Brightest Cluster Galaxy in MACS 1931.8-2635

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    We present new ALMA observations of the molecular gas and far-infrared continuum around the brightest cluster galaxy (BCG) in the cool-core cluster MACS 1931.8-2635. Our observations reveal 1.9±0.3×10101.9 \pm 0.3 \times 10^{10} M_{\odot} of molecular gas, on par with the largest known reservoirs of cold gas in a cluster core. We detect CO(1-0), CO(3-2), and CO(4-3) emission from both diffuse and compact molecular gas components that extend from the BCG center out to 30\sim30 kpc to the northwest, tracing the UV knots and Hα\alpha filaments observed by HST. Due to the lack of morphological symmetry, we hypothesize that the 300\sim300 km s1^{-1} velocity of the CO in the tail is not due to concurrent uplift by AGN jets, rather we may be observing the aftermath of a recent AGN outburst. The CO spectral line energy distribution suggests that molecular gas excitation is influenced by processes related to both star formation and recent AGN feedback. Continuum emission in Bands 6 and 7 arises from dust and is spatially coincident with young stars and nebular emission observed in the UV and optical. We constrain the temperature of several dust clumps to be 10\lesssim 10 K, which is too cold to be directly interacting with the surrounding 4.8\sim 4.8 keV intracluster medium (ICM). The cold dust population extends beyond the observed CO emission and must either be protected from interacting with the ICM or be surrounded by local volumes of ICM that are several keV colder than observed by Chandra.Comment: Accepted for Publication in ApJ, 19 pages, 11 figures. Minor revisions to the discussion and accompanying figur

    Drawing on the Margins of History: English-Language Graphic Narratives in Canada

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    This study analyzes the techniques that Canadian comics life writers develop to construct personal histories. I examine a broad selection of texts including graphic autobiography, biography, memoir, and diary in order to argue that writers and readers can, through these graphic narratives, engage with an eclectic and eccentric understanding of Canadian historical subjects. Contemporary Canadian comics are important for Canadian literature and life writing because they acknowledge the importance of contemporary urban and marginal subcultures and function as representations of people who occasionally experience economic scarcity. I focus on stories of “ordinary” people because their stories have often been excluded from accounts of Canadian public life and cultural history. Following the example of Barbara Godard, Heather Murray, and Roxanne Rimstead, I re-evaluate Canadian literatures by considering the importance of marginal literary products. Canadian comics authors rarely construct narratives about representative figures standing in place of and speaking for a broad community; instead, they create what Murray calls “history with a human face . . . the face of the daily, the ordinary” (“Literary History as Microhistory” 411). My research finds that contemporary Canadian graphic narratives create mundane personal histories using a medium that is inherently attuned to exaggeration and fragmentation. My reading of graphic narrative is based on “autographics,” a recent field of scholarship that analyzes the interactions between visual and verbal forms of communication in works of life writing. I draw on visual rhetorical studies and communication design in order to describe “the distinctive technology and aesthetics of life narrative that emerges in comics” (Whitlock 965). The medium of comics playfully manipulates the discourses of documentary evidence and testimonial authority. At the same time, it gives Canadian authors tools for depicting the experiences of ordinary individuals through a rich collection of emotional, sensorial, and perceptual information. Focusing on the work of such authors as Chester Brown, David Collier, Julie Doucet, Sarah Leavitt, and Seth, I suggest that Canadian comics authors exploit the unique formal properties of the medium of comics in order to interrogate dominant nationalist discourses. They also develop an alternative method for analyzing narratives about the past

    Dust and Molecular Gas in the Brightest Cluster Galaxy in MACS 1931.8-2635

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    We present new Atacama Large Millimeter Array observations of the molecular gas and far-infrared continuum around the brightest cluster galaxy (BCG) in the cool-core cluster MACS 1931.8-2635. Our observations reveal (1.9 ± 0.3) × 10^(10) M⊙ of molecular gas, on par with the largest known reservoirs of cold gas in a cluster core. We detect CO(1−0), CO(3−2), and CO(4−3) emission from both diffuse and compact molecular gas components that extend from the BCG center out to ~30 kpc to the northwest, tracing the UV knots and Hα filaments observed by the Hubble Space Telescope. Due to the lack of morphological symmetry, we hypothesize that the ~300 km s−1 velocity of the CO in the tail is not due to concurrent uplift by active galactic nucleus (AGN) jets; rather, we may be observing the aftermath of a recent AGN outburst. The CO spectral line energy distribution suggests that molecular gas excitation is influenced by processes related to both star formation and recent AGN feedback. Continuum emission in Bands 6 and 7 arises from dust and is spatially coincident with young stars and nebular emission observed in the UV and optical. We constrain the temperature of several dust clumps to be ≾10 K, which is too cold to be directly interacting with the surrounding ~4.8 keV intracluster medium (ICM). The cold dust population extends beyond the observed CO emission and must either be protected from interacting with the ICM or be surrounded by local volumes of ICM that are several keV colder than observed by Chandra

    The PPAR-γ agonist pioglitazone modulates inflammation and induces neuroprotection in parkinsonian monkeys

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    <p>Abstract</p> <p>Background</p> <p>Activation of the peroxisome proliferator-activated receptor gamma (PPAR-γ) has been proposed as a possible neuroprotective strategy to slow down the progression of early Parkinson's disease (PD). Here we report preclinical data on the use of the PPAR-γ agonist pioglitazone (Actos<sup>®</sup>; Takeda Pharmaceuticals Ltd.) in a paradigm resembling early PD in nonhuman primates.</p> <p>Methods</p> <p>Rhesus monkeys that were trained to perform a battery of behavioral tests received a single intracarotid arterial injection of 20 ml of saline containing 3 mg of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Twenty-four hours later the monkeys were assessed using a clinical rating scale, matched accordingly to disability, randomly assigned to one of three groups [placebo (n = 5), 2.5 (n = 6) or 5 (n = 5) mg/kg of pioglitazone] and their treatments started. Three months after daily oral dosing, the animals were necropsied.</p> <p>Results</p> <p>We observed significant improvements in clinical rating score (<it>P </it>= 0.02) in the animals treated with 5 mg/kg compared to placebo. Behavioral recovery was associated with preservation of nigrostriatal dopaminergic markers, observed as higher tyrosine hydroxylase (TH) putaminal optical density (<it>P </it>= 0.011), higher stereological cell counts of TH-ir (<it>P </it>= 0.02) and vesicular monoamine transporter-2 (VMAT-2)-ir nigral neurons (<it>P </it>= 0.006). Stereological cell counts of Nissl stained nigral neurons confirmed neuroprotection (<it>P </it>= 0.017). Pioglitazone-treated monkeys also showed a dose-dependent modulation of CD68-ir inflammatory cells, that was significantly decreased for 5 mg/kg treated animals compared to placebo (<it>P </it>= 0.018). A separate experiment to assess CSF penetration of pioglitazone revealed that 5 mg/kg p.o. induced consistently higher levels than 2.5 mg/kg and 7.5 mg/kg. p.o.</p> <p>Conclusions</p> <p>Our results indicate that oral administration of pioglitazone is neuroprotective when administered early after inducing a parkinsonian syndrome in rhesus monkeys and supports the concept that PPAR-γ is a viable target against neurodegeneration.</p

    Usage of NASA's Near Real-Time Solar and Meteorological Data for Monitoring Building Energy Systems Using RETScreen International's Performance Analysis Module

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    This paper describes building energy system production and usage monitoring using examples from the new RETScreen Performance Analysis Module, called RETScreen Plus. The module uses daily meteorological (i.e., temperature, humidity, wind and solar, etc.) over a period of time to derive a building system function that is used to monitor building performance. The new module can also be used to target building systems with enhanced technologies. If daily ambient meteorological and solar information are not available, these are obtained over the internet from NASA's near-term data products that provide global meteorological and solar information within 3-6 days of real-time. The accuracy of the NASA data are shown to be excellent for this purpose enabling RETScreen Plus to easily detect changes in the system function and efficiency. This is shown by several examples, one of which is a new building at the NASA Langley Research Center that uses solar panels to provide electrical energy for building energy and excess energy for other uses. The system shows steady performance within the uncertainties of the input data. The other example involves assessing the reduction in energy usage by an apartment building in Sweden before and after an energy efficiency upgrade. In this case, savings up to 16% are shown

    Renormalization-group study of Anderson and Kondo impurities in gapless Fermi systems

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    Thermodynamic properties are presented for four magnetic impurity models describing delocalized fermions scattering from a localized orbital at an energy-dependent rate Γ(ϵ)\Gamma(\epsilon) which vanishes precisely at the Fermi level, ϵ=0\epsilon = 0. Specifically, it is assumed that for small ϵ|\epsilon|, Γ(ϵ)ϵr\Gamma(\epsilon)\propto|\epsilon|^r with r>0r>0. The cases r=1r=1 and r=2r=2 describe dilute magnetic impurities in unconventional superconductors, ``flux phases'' of the two-dimensional electron gas, and zero-gap semiconductors. For the nondegenerate Anderson model, the depression of the low-energy scattering rate suppresses mixed valence in favor of local-moment behavior, and leads to a marked reduction in the exchange coupling on entry to the local-moment regime, with a consequent narrowing of the range of parameters within which the impurity spin becomes Kondo-screened. The relationship between the Anderson model and the exactly screened Kondo model with power-law exchange is examined. The intermediate-coupling fixed point identified in the latter model by Withoff and Fradkin (WF) has clear signatures in the thermodynamic properties and in the local magnetic response of the impurity. The underscreened, impurity-spin-one Kondo model and the overscreened, two-channel Kondo model both exhibit a conditionally stable intermediate-coupling fixed point in addition to unstable fixed points of the WF type. In all four models, the presence or absence of particle-hole symmetry plays a crucial role.Comment: 44 two-column REVTex pages, 31 epsf-embedded EPS figures. MINOR formatting changes. To appear in Phys. Rev.

    Dust and Molecular Gas in the Brightest Cluster Galaxy in MACS 1931.8-2635

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    We present new Atacama Large Millimeter Array observations of the molecular gas and far-infrared continuum around the brightest cluster galaxy (BCG) in the cool-core cluster MACS 1931.8-2635. Our observations reveal (1.9 ± 0.3) × 10^(10) M⊙ of molecular gas, on par with the largest known reservoirs of cold gas in a cluster core. We detect CO(1−0), CO(3−2), and CO(4−3) emission from both diffuse and compact molecular gas components that extend from the BCG center out to ~30 kpc to the northwest, tracing the UV knots and Hα filaments observed by the Hubble Space Telescope. Due to the lack of morphological symmetry, we hypothesize that the ~300 km s−1 velocity of the CO in the tail is not due to concurrent uplift by active galactic nucleus (AGN) jets; rather, we may be observing the aftermath of a recent AGN outburst. The CO spectral line energy distribution suggests that molecular gas excitation is influenced by processes related to both star formation and recent AGN feedback. Continuum emission in Bands 6 and 7 arises from dust and is spatially coincident with young stars and nebular emission observed in the UV and optical. We constrain the temperature of several dust clumps to be ≾10 K, which is too cold to be directly interacting with the surrounding ~4.8 keV intracluster medium (ICM). The cold dust population extends beyond the observed CO emission and must either be protected from interacting with the ICM or be surrounded by local volumes of ICM that are several keV colder than observed by Chandra

    Nanosatellite optical downlink experiment: design, simulation, and prototyping

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    The nanosatellite optical downlink experiment (NODE) implements a free-space optical communications (lasercom) capability on a CubeSat platform that can support low earth orbit (LEO) to ground downlink rates>10  Mbps. A primary goal of NODE is to leverage commercially available technologies to provide a scalable and cost-effective alternative to radio-frequency-based communications. The NODE transmitter uses a 200-mW 1550-nm master-oscillator power-amplifier design using power-efficient M-ary pulse position modulation. To facilitate pointing the 0.12-deg downlink beam, NODE augments spacecraft body pointing with a microelectromechanical fast steering mirror (FSM) and uses an 850-nm uplink beacon to an onboard CCD camera. The 30-cm aperture ground telescope uses an infrared camera and FSM for tracking to an avalanche photodiode detector-based receiver. Here, we describe our approach to transition prototype transmitter and receiver designs to a full end-to-end CubeSat-scale system. This includes link budget refinement, drive electronics miniaturization, packaging reduction, improvements to pointing and attitude estimation, implementation of modulation, coding, and interleaving, and ground station receiver design. We capture trades and technology development needs and outline plans for integrated system ground testing.United States. National Aeronautics and Space Administration. Research Fellowship ProgramLincoln Laboratory (Lincoln Scholars)Lincoln Laboratory (Military Fellowship Program)Fundación Obra Social de La Caixa (Fellowship)Samsung FellowshipUnited States. Air Force (Assistant Secretary of Defense for Research & Engineering. Contract FAs872105C0002

    The future of evapotranspiration : global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources

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    The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, and highlight both the outstanding science and applications questions and the actions, especially from a space-based perspective, necessary to advance them
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