90 research outputs found
Fact Sheet no.2: Water Quality and Poultry Disposal Pits
Disposing of poultry that die during grow out is a serious management problem for poultry producers in Northwest Arkansas and across the country. Poultry disposal can affect water quality and the health of wildlife, livestock and people
Characterization of impact pile driving signals during installation of offshore wind turbine foundations
Author Posting. © Acoustical Society of America, 2020. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 147(4), (2020): 2323, doi:10.1121/10.0001035.Impact pile driving creates intense, impulsive sound that radiates into the surrounding environment. Piles driven vertically into the seabed generate an azimuthally symmetric underwater sound field whereas piles driven on an angle will generate an azimuthally dependent sound field. Measurements were made during pile driving of raked piles to secure jacket foundation structures to the seabed in waters off the northeastern coast of the U.S. at ranges between 500 m and 15 km. These measurements were analyzed to investigate variations in rise time, decay time, pulse duration, kurtosis, and sound received levels as a function of range and azimuth. Variations in the radiated sound field along opposing azimuths resulted in differences in measured sound exposure levels of up to 10 dB and greater due to the pile rake as the sound propagated in range. The raked pile configuration was modeled using an equivalent axisymmetric FEM model to describe the azimuthally dependent measured sound fields. Comparable sound level differences in the model results confirmed that the azimuthal discrepancy observed in the measured data was due to the inclination of the pile being driven relative to the receiver.This paper was presented at the fifth International Meeting on The Effects of Noise on Aquatic Life held in Den Haag, July 2019. Study concept, oversight, and funding for the experiment were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program, Washington, DC, under Contract No. M15PC00002, Task Order M16PD00025. Collaborators in this project include Randy Gallien and Anwar Khan (HDR, Inc.).2020-10-1
3C 220.3: a radio galaxy lensing a submillimeter galaxy
Herschel Space Observatory photometry and extensive multiwavelength followup
have revealed that the powerful radio galaxy 3C 220.3 at z=0.685 acts as a
gravitational lens for a background submillimeter galaxy (SMG) at z=2.221. At
an observed wavelength of 1mm, the SMG is lensed into three distinct images. In
the observed near infrared, these images are connected by an arc of 1.8" radius
forming an Einstein half-ring centered near the radio galaxy. In visible light,
only the arc is apparent. 3C 220.3 is the only known instance of strong
galaxy-scale lensing by a powerful radio galaxy not located in a galaxy cluster
and therefore it offers the potential to probe the dark matter content of the
radio galaxy host. Lens modeling rejects a single lens, but two lenses centered
on the radio galaxy host A and a companion B, separated by 1.5", provide a fit
consistent with all data and reveal faint candidates for the predicted fourth
and fifth images. The model does not require an extended common dark matter
halo, consistent with the absence of extended bright X-ray emission on our
Chandra image. The projected dark matter fractions within the Einstein radii of
A (1.02") and B (0.61") are about 0.4 +/- 0.3 and 0.55 +/- 0.3. The mass to
i-band light ratios of A and B, M/L ~ 8 +/- 4 Msun/Lsun, appear comparable to
those of radio-quiet lensing galaxies at the same redshift in the CASTLES, LSD,
and SL2S samples. The lensed SMG is extremely bright with observed f(250um) =
440mJy owing to a magnification factor mu~10. The SMG spectrum shows luminous,
narrow CIV 154.9nm emission, revealing that the SMG houses a hidden quasar in
addition to a violent starburst. Multicolor image reconstruction of the SMG
indicates a bipolar morphology of the emitted ultraviolet (UV) light suggestive
of cones through which UV light escapes a dust-enshrouded nucleus.Comment: 17 pages, 14 Figures, accepted for publication in Ap
The Chandra Multi-Wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-ray Selected AGN
From optical spectroscopy of X-ray sources observed as part of ChaMP, we
present redshifts and classifications for a total of 1569 Chandra sources from
our targeted spectroscopic follow up using the FLWO, SAAO, WIYN, CTIO, KPNO,
Magellan, MMT and Gemini telescopes, and from archival SDSS spectroscopy. We
classify the optical counterparts as 50% BLAGN, 16% NELG, 14% ALG, and 20%
stars. We detect QSOs out to z~5.5 and galaxies out to z~3. We have compiled
extensive photometry from X-ray to radio bands. Together with our spectroscopic
information, this enables us to derive detailed SEDs for our extragalactic
sources. We fit a variety of templates to determine bolometric luminosities,
and to constrain AGN and starburst components where both are present. While
~58% of X-ray Seyferts require a starburst event to fit observed photometry
only 26% of the X-ray QSO population appear to have some kind of star formation
contribution. This is significantly lower than for the Seyferts, especially if
we take into account torus contamination at z>1 where the majority of our X-ray
QSOs lie. In addition, we observe a rapid drop of the percentage of starburst
contribution as X-ray luminosity increases. This is consistent with the
quenching of star formation by powerful QSOs, as predicted by the merger model,
or with a time lag between the peak of star formation and QSO activity. We have
tested the hypothesis that there should be a strong connection between X-ray
obscuration and star-formation but we do not find any association between X-ray
column density and star formation rate both in the general population or the
star-forming X-ray Seyferts. Our large compilation also allows us to report
here the identification of 81 XBONG, 78 z>3 X-ray sources and 8 Type-2 QSO
candidates. Also we have identified the highest redshift (z=5.4135) X-ray
selected QSO with optical spectroscopy.Comment: 17 pages, 16 figures, accepted for publication in ApJS. Full data
table and README file can be found online at
http://hea-www.harvard.edu/~pgreen/Papers.htm
Gauge Invariant Smearing and Matrix Correlators using Wilson Fermions at beta=6.2
We present an investigation of gauge invariant smearing for Wilson fermions
on a lattice at . We demonstrate a smearing
algorithm that allows a substantial improvement in the determination of the
baryon spectrum obtained using propagators smeared at both source and sink, at
only a small computational cost. We investigate the matrix of correlators
constructed from local and smeared operators, and are able to expose excited
states of both the mesons and baryons.Comment: at lattice `92. 4 pages latex + 3 postscript figures. Edinburgh
preprint: 92/51
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Very High Density Clumps and Outflowing Winds in QSO Broad-Line Regions
Intercomparison of the spectra of seven high-luminosity quasi-stellar objects (QSOs) shows that there is a gradation of properties in their broad emission-line regions (BELRs) that can be understood as differing mixtures of different gas components. Six of these seven objects have unusually narrow BELR profiles, which greatly facilitates the disentangling of blends and measuring of weak lines. In the QSO 0207 - 398, the BELR is made up of at least three kinematically distinct components; its spectrum is in fact a composite of the spectra of the more homogeneous BELRs in the QSOs at either end of our sequence of properties. This paper focuses on the properties of the line-emitting region in Q0207 - 398 dubbed component "A," which has sharp (FWHM = 1000 km s^-1^), symmetric line profiles centered at zero velocity. We find that these lines are emitted in very dense (n_H_ ~ 10^12.5^ cm^-3^) gas at a characteristic radius r ~ 10^17.7^ cm from the continuum source and which emits a low-ionization spectrum including strong A1 III λ1857. The second component, "B," in Q0207 - 398 is the subject of a companion paper. It is characterized by high-ionization lines such as N V λ1240, O VI λ1034, and C IV λ1549 with profiles that peak at zero velocity but have a blue tail extending out to - 11,000 km s^-1^. It receives about the same incident flux as component A and therefore may lie at the same distance from the continuum source, but it is significantly less dense (n_H_ ~ 10^11^ cm^-3^). The remaining line emission from Q0207 - 398 is attributed to a component "C" which has reasonably broad (FWHM = 2000 km s^-1^), symmetric line profiles centered at zero velocity. Most of the Lyα and C III] λ1909 emission comes from this region, but it also contributes to C IV, N V, and many other lines. The spectrum of component C is in fact quite similar to that of "normal" QSOs. We interpret component A as the dense source for radiatively accelerated, outward flowing gas which we see as component B. Component A may consist of the ablated atmospheres of stars which have strayed too close to the QSO nucleus. In addition, component A's velocity width is essentially the same as that of the stellar population in the nucleus of M87. From the radius and velocity, we infer the presence of a central mass of only 10^7^-10^8^ M_sun_, if we are measuring virial motions and if the ionizing continuum is isotropic. An alternate possibility is that the narrow single-peaked component A profile comes from a rotating torus/accretion disk, probably seen face-on, in which case it is impossible to measure the central mass. We discuss the similarity between Mg II-type broad absorption line (BAL) QSOs and Q0207 - 398, which does not have BALs. In fact, the two Mg II-type BAL objects in our sample have spectra almost exactly like that of Q0207 - 398, except that component B is seen in absorption rather than in emission.Astronom
A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Early Data Release
We present a catalog of 224 broad absorption line quasars (BALQSOs) from the
Sloan Digital Sky Survey's Early Data Release Quasar Catalog, including a
relatively complete and homogeneous subsample of 131 BALQSOs. Since the
identification of BALQSOs is subject to considerable systematic uncertainties,
we attempt to create a complete sample of SDSS BALQSOs by combining the results
of two automated selection algorithms and a by-eye classification scheme. One
of these automated algorithms finds broad absorption line troughs by comparison
with a composite quasar spectrum. We present the details of this algorithm and
compare this method to that which uses a power-law fit to the continuum. The
BALQSOs in our sample are further classified as high-ionization BALQSOs
(HiBALs), low-ionization BALQSOs (LoBALs), and BALQSOs with excited iron
absorption features (FeLoBALs); composite spectra of each type are presented.
We further present a study of the properties of the BALQSOs in terms of the
balnicity distribution, which rises with decreasing balnicity. This
distribution of balnicities suggests that the fraction of quasars with
intrinsic outflows may be significantly underestimated.Comment: 36 pages, 7 figures (1 color), 2 tables, accepted by A
Role of Complement Activation in Obliterative Bronchiolitis Post Lung Transplantation
Obliterative bronchiolitis (OB) post lung transplantation involves IL-17 regulated autoimmunity to type V collagen and alloimmunity, which could be enhanced by complement activation. However, the specific role of complement activation in lung allograft pathology, IL-17 production, and OB are unknown. The current study examines the role of complement activation in OB. Complement regulatory protein (CRP) (CD55, CD46, Crry/CD46) expression was down regulated in human and murine OB; and C3a, a marker of complement activation, was up regulated locally. IL-17 differentially suppressed Crry expression in airway epithelial cells in vitro. Neutralizing IL-17 recovered CRP expression in murine lung allografts and decreased local C3a production. Exogenous C3a enhanced IL-17 production from alloantigen or autoantigen (type V collagen) reactive lymphocytes. Systemically neutralizing C5 abrogated the development of OB, reduced acute rejection severity, lowered systemic and local levels of C3a and C5a, recovered CRP expression, and diminished systemic IL-17 and IL-6 levels. These data indicated that OB induction is in part complement dependent due to IL-17 mediated down regulation of CRPs on airway epithelium. C3a and IL-17 are part of a feed forward loop that may enhance CRP down regulation, suggesting that complement blockade could be a therapeutic strategy for OB
The HMGB1-RAGE axis mediates traumatic brain injury-induced pulmonary dysfunction in lung transplantation
Traumatic brain injury (TBI) results in systemic inflammatory responses that affect the lung. This is especially critical in the setting of lung transplantation, where more than half of donor allografts are obtained postmortem from individuals with TBI. The mechanism by which TBI causes pulmonary dysfunction remains unclear but may involve the interaction of high-mobility group box-1 (HMGB1) protein with the receptor for advanced glycation end products (RAGE). To investigate the role of HMGB1 and RAGE in TBI-induced lung dysfunction, RAGE-sufficient (wild-type) or RAGE-deficient (RAGE(-/-)) C57BL/6 mice were subjected to TBI through controlled cortical impact and studied for cardiopulmonary injury. Compared to control animals, TBI induced systemic hypoxia, acute lung injury, pulmonary neutrophilia, and decreased compliance (a measure of the lungs' ability to expand), all of which were attenuated in RAGE(-/-) mice. Neutralizing systemic HMGB1 induced by TBI reversed hypoxia and improved lung compliance. Compared to wild-type donors, lungs from RAGE(-/-) TBI donors did not develop acute lung injury after transplantation. In a study of clinical transplantation, elevated systemic HMGB1 in donors correlated with impaired systemic oxygenation of the donor lung before transplantation and predicted impaired oxygenation after transplantation. These data suggest that the HMGB1-RAGE axis plays a role in the mechanism by which TBI induces lung dysfunction and that targeting this pathway before transplant may improve recipient outcomes after lung transplantation
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