369 research outputs found
Studies of group velocity reduction and pulse regeneration with and without the adiabatic approximation
We present a detailed semiclassical study on the propagation of a pair of
optical fields in resonant media with and without adiabatic approximation. In
the case of near and on resonance excitation, we show detailed calculation,
both analytically and numerically, on the extremely slowly propagating probe
pulse and the subsequent regeneration of a pulse via a coupling laser. Further
discussions on the adiabatic approximation provide many subtle understandings
of the process including the effect on the band width of the regenerated
optical field. Indeed, all features of the optical pulse regeneration and most
of the intricate details of the process can be obtained with the present
treatment without invoke a full field theoretical method. For very far off
resonance excitation, we show that the analytical solution is nearly detuning
independent, a surprising result that is vigorously tested and compared to
numerical calculations with very good agreement.Comment: 13 pages, 15 figures, submitted to Phys. Rev.
Limits on precursor and afterglow radio emission from a fast radio burst in a star-forming galaxy
We present a new fast radio burst at 920 MHz discovered during commensal
observations conducted with the Australian Square Kilometre Array Pathfinder
(ASKAP) as part of the Commensal Real-time ASKAP Fast Transients (CRAFT)
survey. FRB 191001 was detected at a dispersion measure (DM) of 506.92(4) pc
cm and its measured fluence of 143(15) Jy ms is the highest of the
bursts localized to host galaxies by ASKAP to date. The sub-arcsecond
localisation of the FRB provided by ASKAP reveals that the burst originated in
the outskirts of a highly star-forming spiral in a galaxy pair at redshift
. Radio observations show no evidence for a compact persistent
radio source associated with the FRB 191001 above a flux density of Jy.
However, we detect diffuse synchrotron radio emission from the disk of the host
galaxy that we ascribe to ongoing star formation. FRB 191001 was also detected
as an image-plane transient in a single 10-s snapshot with a flux density of
19.3 mJy in the low-time-resolution visibilities obtained simultaneously with
CRAFT data. The commensal observation facilitated a search for repeating and
slowly varying radio emissions 8 hrs before and 1 hr after the burst. We found
no variable radio emission on timescales ranging from 1 ms to 1.4 hr. We report
our upper limits and briefly review FRB progenitor theories in the literature
which predict radio afterglows. Our data are still only weakly constraining of
any afterglows at the redshift of the FRB. Future commensal observations of
more nearby and bright FRBs will potentially provide stronger constraints.Comment: 12 pages, 6 figures, Accepted for publication in ApJ Letter
Cosmological results from the RAISIN survey: Using type Ia supernovae in the near infrared as a novel path to measure the dark energy equation of state
Jones et al.Type Ia supernovae (SNe Ia) are more precise standardizable candles when measured in the near-infrared (NIR) than in the optical. With this motivation, from 2012 to 2017 we embarked on the RAISIN program with the Hubble Space Telescope (HST) to obtain rest-frame NIR light curves for a cosmologically distant sample of 37 SNe Ia (0.2 ≲ z ≲ 0.6) discovered by Pan-STARRS and the Dark Energy Survey. By comparing higher-z HST data with 42 SNe Ia at z < 0.1 observed in the NIR by the Carnegie Supernova Project, we construct a Hubble diagram from NIR observations (with only time of maximum light and some selection cuts from optical photometry) to pursue a unique avenue to constrain the dark energy equation-of-state parameter, w. We analyze the dependence of the full set of Hubble residuals on the SN Ia host galaxy mass and find Hubble residual steps of size ∼0.06-0.1 mag with 1.5σ−2.5σ significance depending on the method and step location used. Combining our NIR sample with cosmic microwave background constraints, we find 1 + w = −0.17 ± 0.12 (statistical + systematic errors). The largest systematic errors are the redshift-dependent SN selection biases and the properties of the NIR mass step. We also use these data to measure H0 = 75.9 ± 2.2 km s−1 Mpc−1 from stars with geometric distance calibration in the hosts of eight SNe Ia observed in the NIR versus H0 = 71.2 ± 3.8 km s−1 Mpc−1 using an inverse distance ladder approach tied to Planck. Using optical data, we find 1 + w = −0.10 ± 0.09, and with optical and NIR data combined, we find 1 + w = −0.06 ± 0.07; these shifts of up to ∼0.11 in w could point to inconsistency in the optical versus NIR SN models. There will be many opportunities to improve this NIR measurement and better understand systematic uncertainties through larger low-z samples, new light-curve models, calibration improvements, and eventually by building high-z samples from the Roman Space Telescope.Support for this work was provided by a Gordon and Betty Moore Foundation postdoctoral fellowship to D.O.J.at the University of California, Santa Cruz, and by NASA through the NASA Hubble Fellowship grant HF2-51462.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. The Cambridge University team acknowledges support from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC grant agreement No. 101002652); the ASTROSTAT-II collaboration, enabled by the Horizon 2020, EU grant agreement No. 873089; and the Cambridge Centre for Doctoral Training in Data-Intensive Science funded by the UK Science and Technology Facilities Council (STFC). L.G. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN), the Agencia Estatal de Investigación (AEI) 10.13039/ 501100011033, and the European Social Fund (ESF) “Investing in your future” under the 2019 Ramón y Cajal program RYC2019027683-I and the PID2020-115253GA-I00 HOSTFLOWS project, from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016, and the program Unidad de Excelencia Mara de Maeztu CEX2020-001058-M. M. R.S. is supported by the NSF Graduate Research Fellowship Program under grant 1842400. The UCSC team is supported in part by NASA grants 14-WPS14-0048, NNG16PJ34C, and NNG17PX03C; NSF grants AST-1518052 and AST-1815935; NASA through grant No. AR-14296 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; and fellowships from the Alfred P. Sloan Foundation and the David and Lucile Packard Foundation to R.J.F. Based on observations with the NASA/ESA Hubble Space Telescope obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for program Nos. 13046 and 14216 was provided through grants from the STScI under NASA contract NAS5-26555. The Carnegie Supernova Project has been supported by the National Science Foundation under grants AST0306969, AST0607438, AST1008343, AST1613426, AST1613455, and AST1613472. L.K. thanks the UKRI Future Leaders Fellowship for support through the grant MR/T01881X/ 1. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology.Peer reviewe
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Negotiating Value: Comparing Human and Animal Fracture Care in Industrial Societies
At the beginning of the twentieth-century, human and veterinary surgeons faced the challenge of a medical marketplace transformed by technology. The socio-economic value ascribed to their patients – people and domestic animals – was changing, reflecting the increasing mechanisation of industry and the decreasing dependence of society upon non-human animals for labour. In human medicine, concern for the economic consequences of fractures “pathologised” any significant level of post-therapeutic disability, a productivist perspective contrary to the traditional corpus of medical values. In contrast, veterinarians adapted to the mechanisation of horse-power by shifting their primary professional interest to companion animals; a type of veterinary patient generally valued for the unique emotional attachment of the owner, and not the productive capacity of the animal. The economic rationalisation of human fracture care and the “sentimental” transformation of veterinary orthopaedic expertise indicates how these specialists utilised increasingly convergent rhetorical arguments to justify the application of innovative fracture care technologies to their humans and animal patients. Keywords: Fracture care, Industrialisation, Veterinary History, Human/animal relation
The Lantern, 2011-2012
• Frangipani • A Shadow • Dear Anne, In this Place, Stringbean Girls • Back to a Dandelion • How to Plant a Room • Swimming Pool Poem 30 • The Naming of Daughters • Berman Museum Photographs • Truth or Dare • The Song of Remembrance, L\u27vov, Poland, 1940 • Headlights • Prayer of Thanks • Numbers Game • Pediment • Home Sick • Lust • Sand Lining Instructions • A-A-Ask a Question • Flash Cards • Columbus Day • Mr. Yoest Gives His Report to the Police Officers on Wednesday Night • Gender Trouble • The Internet Connection at Ursinus College • Assuming You\u27ll Still be Here • 10/28/11, Third Poem • October • Actions that Affirm and Confirm Us as a Community • Why I Hate The Lantern • Confessions of an Ex-Vegetarian • Run • Lunch at Caltort • Schemers • You Will Make Beautiful Babies in America • The Black Dirt Region • Il Travatore • Ghost Story • Blue Eyes and Sunny Skies • A Little Sincerity • The Bookstore • The Opposite of Serendipity • The Human Doll • Evil Deeds • Francesca • Sunday Morning • Jersey Aesthetic • Jump! • Behind Reimert • Seaweed in New Zealand • Tombee de L\u27elegance • The Window • Esperando • Rainbow to the Heavens • Encased • In Springtime • A Fiesolan Monk\u27s Room • Inside a Bone • Neon Indian • Moments of Clarity • OneFeral: A Feral Self-Portrait • Cover Image: The Conquerorhttps://digitalcommons.ursinus.edu/lantern/1177/thumbnail.jp
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
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