556 research outputs found

    Economics of Dairy Manure Management in Iowa

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    Dairy producers have many duties to carry out in their dairy operations, one of which is storing, handling and applying manure. Manure handling can be a significant cost on most dairies even when considering the value of the nutrients in the manure. Seldom do producers consider their costs of handling and applying manure on a per hundredweight (cwt) of milk sold basis like they do with many of their other costs. This project encompassed surveys of manure management systems and nutrient management practices on 22 Iowa Dairy Farms, including economic costs and returns. Key findings are that the cost of storing, hauling and applying manure averaged 306.13percowor306.13 per cow or 1.33 per / cwt. If we subtract the nutrient value of the manure applied (using book values and assuming perfect utilization) the net cost of storing, hauling and applying manure averaged 104.10percowor104.10 per cow or 0.45per/cwt.Thetiestallbarnshadacumulativecostpercwt.of0.45 per / cwt. The tie stall barns had a cumulative cost per cwt. of 1.42; the mattress/waterbed barns had a cumulative cost per cwt. of 1.50;the2stagesandsystemshadacumulativecostpercwt.of1.50; the 2 stage sand systems had a cumulative cost per cwt. of 0.97; the 1 stage sand systems had a cumulative cost per cwt. of 1.44;andthedriedmanuresolidbarnshadacumulativecostpercwt.of1.44; and the dried manure solid barns had a cumulative cost per cwt. of 1.24

    Student reactions to traumatic material in literature: Implications for trigger warnings

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    Introduction While trigger warnings have garnered significant debate, few studies have investigated how students typically respond to potentially triggering material. Method In this study, three hundred and fifty-five undergraduate students from four universities read a passage describing incidences of both physical and sexual assault. Longitudinal mea- sures of subjective distress, PTSD symptoms, and emotional reactivity were taken. Results Greater than 96% of participants read the triggering passage even when given a non-trig- gering alternative to read. Of those who read the triggering passage, those with triggering traumas did not report more distress although those with higher PTSD scores did. Two weeks later, those with trigger traumas and/or PTSD did not report an increase in trauma symptoms as a result of reading the triggering passage. Conclusions Students with relevant traumas do not avoid triggering material and the effects appear to be brief. Students with PTSD do not report an exacerbation of symptoms two weeks later as a function of reading the passage

    Science Journals in the Preschool Classroom

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    Abstract We believe that science journals can be used in the preschool classroom as tools for supporting and assessing children's learning of science-and literacy-relevant content and procedures. To support this argument, we review changes in attitudes about the cognitive competencies of preschoolers and in teaching and learning expectations for early childhood education. We describe practical aspects of using science notebooks with this age group and discuss specific ways that journals support children's learning. Finally, the role of journals in assessment is discussed

    An X-Ray View of the Jet-Cycle in the Radio Loud AGN 3C120

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    We present a study of the central engine in the broad-line radio galaxy 3C120 using a multi-epoch analysis of a deep XMM-Newton observation and two deep Suzaku pointings (in 2012). In order to place our spectral data into the context of the disk-disruption/jet-ejection cycles displayed by this object, we monitor the source in the UV/X-ray bands, and in the radio band. We find three statistically acceptable spectral models, a disk-reflection model, a jet-model and a jet+disk model. Despite being good descriptions of the data, the disk-reflection model violates the radio constraints on the inclination, and the jet-model has a fine-tuning problem, requiring a jet contribution exceeding that expected. Thus, we argue for a composite jet+disk model. Within the context of this model, we verify the basic predictions of the jet-cycle paradigm, finding a truncated/refilling disk during the Suzaku observations and a complete disk extending down to the innermost stable circular orbit (ISCO) during the XMM-Newton observation. The idea of a refilling disk is further supported by the detection of the ejection of a new jet knot approximately one month after the Suzaku pointings. We also discover a step-like event in one of the Suzaku pointings in which the soft band lags the hard band. We suggest that we are witnessing the propagation of a disturbance from the disk into the jet on a timescale set by the magnetic field.Comment: 14 pages, 10 figures, accepted for publication in Ap

    Blunt Liver Trauma at Sunnybrook Medical Centre: A 13 Year Experience

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    Between June 1, 1976 and June 30, 1989 The Regional Trauma Unit at Sunnybrook Medical Centre in Toronto, Ontario, Canada received 3730 patients. Of these 335 (9%) sustained a liver injury, 95% being due to blunt trauma. Open peritoneal lavage was performed on 80% of liver trauma patients (267/335), 99% being true positive

    A Hard Look at NGC 5347: Revealing a Nearby Compton-thick AGN

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    Current measurements show that the observed fraction of Compton-thick (CT) active galactic nuclei (AGN) is smaller than the expected values needed to explain the cosmic X-ray background. Prior fits to the X-ray spectrum of the nearby Seyfert-2 galaxy NGC 5347 (z = 0.00792, D = 35.5 Mpc ) have alternately suggested a CT and Compton-thin source. Combining archival data from Suzaku, Chandra, and—most importantly—new data from NuSTAR, ... See full text for complete abstrac

    NuSTAR and Suzaku X-ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk

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    We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin a>0.9 accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the inner disk reflection model, and we find that a compact corona is consistent with the observed features.Comment: 20 pages, 12 figures, accepted for publication in Ap

    Self-consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection Emission

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    Continuum and reflection spectral models have each been widely employed in measuring the spins of accreting black holes. However, the two approaches have not been implemented together in a photon-conserving, self-consistent framework. We develop such a framework using the black hole X-ray binary GX 339–4 as a touchstone source, and we demonstrate three important ramifications. (1) Compton scattering of reflection emission in the corona is routinely ignored, but is an essential consideration given that reflection is linked to the regimes with strongest Comptonization. Properly accounting for this causes the inferred reflection fraction to increase substantially, especially for the hard state. Another important impact of the Comptonization of reflection emission by the corona is the downscattered tail. Downscattering has the potential to mimic the relativistically broadened red wing of the Fe line associated with a spinning black hole. (2) Recent evidence for a reflection component with a harder spectral index than the power-law continuum is naturally explained as Compton-scattered reflection emission. (3) Photon conservation provides an important constraint on the hard state's accretion rate. For bright hard states, we show that disk truncation to large scales R ≫ R[subscript ISCO] is unlikely as this would require accretion rates far in excess of the observed [dotM] of the brightest soft states. Our principal conclusion is that when modeling relativistically broadened reflection, spectral models should allow for coronal Compton scattering of the reflection features, and when possible, take advantage of the additional constraining power from linking to the thermal disk component.United States. National Aeronautics and Space Administration (PF5-160144

    NuSTAR Reveals the Comptonizing Corona of the Broad-Line Radio Galaxy 3C 382

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    Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of Γ=1.68−0.02+0.03\Gamma=1.68^{+0.03}_{-0.02}, while the photon-index of the higher flux spectrum is Γ=1.78−0.03+0.02\Gamma=1.78^{+0.02}_{-0.03}. Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from kTe=330±30kT_e=330\pm 30 keV in the low flux data to 231−88+50231^{+50}_{-88} keV in the high flux observation. This cooling behavior is typical of Comptonizing corona in Seyfert galaxies and is distinct from the variations observed in jet-dominated sources. In the high flux observation, simultaneous Swift data are leveraged to obtain a broadband spectral energy distribution and indicates that the corona intercepts ∼10\sim 10% of the optical and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection features, with no detectable relativistic Fe Kα\alpha line, that may be best explained by an outflowing corona combined with an ionized inner accretion disk.Comment: 8 pages, 8 figures, accepted by Ap
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