132 research outputs found
Full-Depth Reclamation (FDR) for Preventive Maintenance: SR 65 Analysis
The INDOT and HNTB field inspection and management team for the I-65 Northwest Indiana Design-Build-Best Value project in Lake County, Indiana, will discuss differences in the implementation and reporting requirements for field personnel via this project delivery method versus a traditional design-bidbuild INDOT project
Full-Depth Reclamation (FDR) for Preventive Maintenance: SR 65 Analysis
The INDOT and HNTB field inspection and management team for the I-65 Northwest Indiana Design-Build-Best Value project in Lake County, Indiana, will discuss differences in the implementation and reporting requirements for field personnel via this project delivery method versus a traditional design-bidbuild INDOT project
Grouping Promotes Equality: The Effect of Recipient Grouping on Allocation of Limited Medical Resources
Decisions about allocation of scarce resources, such as transplant organs, often entail a trade-off between efficiency (i.e., maximizing the total benefit) and fairness (i.e., dividing resources equally). In three studies, we used a hypothetical scenario for transplant-organ allocation to examine allocation to groups versus individuals. Study 1 demonstrated that allocation to individuals is more efficient than allocation to groups. Study 2 identified a factor that triggers the use of fairness over efficiency: presenting the beneficiaries as one arbitrary group rather than two. Specifically, when beneficiaries were presented as one group, policymakers tended to allocate resources efficiently, maximizing total benefit. However, when beneficiaries were divided into two arbitrary groups (by hospital name), policymakers divided resources more equally across the groups, sacrificing efficiency. Study 3 replicated this effect using a redundant attribute (prognosis) to create groups and found evidence for a mediator of the grouping effect—the use of individualizing information to rationalize a more equitable allocation decision
CCAT-prime: a novel telescope for submillimeter astronomy
The CCAT-prime telescope is a 6-meter aperture, crossed-Dragone telescope,
designed for millimeter and sub-millimeter wavelength observations. It will be
located at an altitude of 5600 meters, just below the summit of Cerro
Chajnantor in the high Atacama region of Chile. The telescope's unobscured
optics deliver a field of view of almost 8 degrees over a large, flat focal
plane, enabling it to accommodate current and future instrumentation fielding
>100k diffraction-limited beams for wavelengths less than a millimeter. The
mount is a novel design with the aluminum-tiled mirrors nested inside the
telescope structure. The elevation housing has an integrated shutter that can
enclose the mirrors, protecting them from inclement weather. The telescope is
designed to co-host multiple instruments over its nominal 15 year lifetime. It
will be operated remotely, requiring minimum maintenance and on-site activities
due to the harsh working conditions on the mountain. The design utilizes
nickel-iron alloy (Invar) and carbon-fiber-reinforced polymer (CFRP) materials
in the mirror support structure, achieving a relatively temperature-insensitive
mount. We discuss requirements, specifications, critical design elements, and
the expected performance of the CCAT-prime telescope. The telescope is being
built by CCAT Observatory, Inc., a corporation formed by an international
partnership of universities. More information about CCAT and the CCAT-prime
telescope can be found at www.ccatobservatory.org.Comment: Event: SPIE Astronomical Telescope + Instrumentation, 2018, Austin,
Texas, USA; Proceedings Volume 10700, Ground-based and Airborne Telescopes
VII; 107005X (2018
Molecular Gas in Redshift 6 Quasar Host Galaxies
We report our new observations of redshifted carbon monoxide emission from
six z~6 quasars, using the PdBI. CO (6-5) or (5-4) line emission was detected
in all six sources. Together with two other previous CO detections, these
observations provide unique constraints on the molecular gas emission
properties in these quasar systems close to the end of the cosmic reionization.
Complementary results are also presented for low-J CO lines observed at the GBT
and the VLA, and dust continuum from five of these sources with the SHARC-II
bolometer camera at the CSO. We then present a study of the molecular gas
properties in our combined sample of eight CO-detected quasars at z~6. The
detections of high-order CO line emission in these objects indicates the
presence of highly excited molecular gas, with estimated masses on the order of
10^10 M_sun within the quasar host galaxies. No significant difference is found
in the gas mass and CO line width distributions between our z~6 quasars and
samples of CO-detected quasars and submillimeter galaxies.
Most of the CO-detected quasars at z~6 follow the far infrared-CO luminosity
relationship defined by actively star-forming galaxies at low and high
redshifts. This suggests that ongoing star formation in their hosts contributes
significantly to the dust heating at FIR wavelengths. The result is consistent
with the picture of galaxy formation co-eval with supermassive black hole
(SMBH) accretion in the earliest quasar-host systems. We investigate the black
hole--bulge relationships of our quasar sample, using the CO dynamics as a
tracer for the dynamical mass of the quasar host. The results place important
constraints on the formation and evolution of the most massive SMBH-spheroidal
host systems at the highest redshift.Comment: 34 pages, 8 figures, accepted for publication in Ap
Software systems for operation, control, and monitoring of the EBEX instrument
We present the hardware and software systems implementing autonomous
operation, distributed real-time monitoring, and control for the EBEX
instrument. EBEX is a NASA-funded balloon-borne microwave polarimeter designed
for a 14 day Antarctic flight that circumnavigates the pole. To meet its
science goals the EBEX instrument autonomously executes several tasks in
parallel: it collects attitude data and maintains pointing control in order to
adhere to an observing schedule; tunes and operates up to 1920 TES bolometers
and 120 SQUID amplifiers controlled by as many as 30 embedded computers;
coordinates and dispatches jobs across an onboard computer network to manage
this detector readout system; logs over 3~GiB/hour of science and housekeeping
data to an onboard disk storage array; responds to a variety of commands and
exogenous events; and downlinks multiple heterogeneous data streams
representing a selected subset of the total logged data. Most of the systems
implementing these functions have been tested during a recent engineering
flight of the payload, and have proven to meet the target requirements. The
EBEX ground segment couples uplink and downlink hardware to a client-server
software stack, enabling real-time monitoring and command responsibility to be
distributed across the public internet or other standard computer networks.
Using the emerging dirfile standard as a uniform intermediate data format, a
variety of front end programs provide access to different components and views
of the downlinked data products. This distributed architecture was demonstrated
operating across multiple widely dispersed sites prior to and during the EBEX
engineering flight.Comment: 11 pages, to appear in Proceedings of SPIE Astronomical Telescopes
and Instrumentation 2010; adjusted metadata for arXiv submissio
BLAST: Correlations in the Cosmic Far-Infrared Background at 250, 350, and 500 microns Reveal Clustering of Star-Forming Galaxies
We detect correlations in the cosmic far-infrared background due to the
clustering of star-forming galaxies in observations made with the Balloon-borne
Large Aperture Submillimeter Telescope, BLAST, at 250, 350, and 500 microns. We
perform jackknife and other tests to confirm the reality of the signal. The
measured correlations are well fit by a power law over scales of 5-25
arcminutes, with Delta I/I = 15.1 +/- 1.7%. We adopt a specific model for
submillimeter sources in which the contribution to clustering comes from
sources in the redshift ranges 1.3 <= z <= 2.2, 1.5 <= z <= 2.7, and 1.7 <= z
<= 3.2, at 250, 350, and 500 microns, respectively. With these distributions,
our measurement of the power spectrum, P(k_theta), corresponds to linear bias
parameters, b = 3.8 +/- 0.6, 3.9 +/- 0.6 and 4.4 +/- 0.7, respectively. We
further interpret the results in terms of the halo model, and find that at the
smaller scales, the simplest halo model fails to fit our results. One way to
improve the fit is to increase the radius at which dark matter halos are
artificially truncated in the model, which is equivalent to having some
star-forming galaxies at z >= 1 located in the outskirts of groups and
clusters. In the context of this model we find a minimum halo mass required to
host a galaxy is log (M_min / M_sun) = 11.5 (+0.4/-0.1), and we derive
effective biases $b_eff = 2.2 +/- 0.2, 2.4 +/- 0.2, and 2.6 +/- 0.2, and
effective masses log (M_eff / M_sun) = 12.9 +/- 0.3, 12.8 +/- 0.2, and 12.7 +/-
0.2, at 250, 350, and 500 microns, corresponding to spatial correlation lengths
of r_0 = 4.9, 5.0, and 5.2 +/- 0.7 h^-1 Mpc, respectively. Finally, we discuss
implications for clustering measurement strategies with Herschel and Planck.Comment: Accepted for publication in the Astrophysical Journal. Maps and other
results available at http://blastexperiment.info
Radio and mid-infrared identification of BLAST source counterparts in the Chandra Deep Field South
We have identified radio and/or mid-infrared counterparts to 198 out of 350
sources detected at >=5 sigma over ~ 9 square degrees centered on the Chandra
Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter
Telescope (BLAST) at 250, 350 and 500 um. We have matched 114 of these
counterparts to optical sources with previously derived photometric redshifts
and fitted SEDs to the BLAST fluxes and fluxes at 70 and 160 um acquired with
the Spitzer Space Telescope. In this way, we have constrained dust
temperatures, total far-infrared/sub-millimeter luminosities and star formation
rates for each source. Our findings show that on average, the BLAST sources lie
at significantly lower redshifts and have significantly lower rest-frame dust
temperatures compared to submm sources detected in surveys conducted at 850 um.
We demonstrate that an apparent increase in dust temperature with redshift in
our sample arises as a result of selection effects. Finally, we provide the
full multi-wavelength catalog of >= 5 sigma BLAST sources contained within the
complete ~ 9 square degree survey area.Comment: Published in the Astrophysical Journal: 2009, ApJ, 703, 285. 23
pages, 13 figures. Data available at http://blastexperiment.inf
The Case against a Smoker's License
Tobacco continues to kill millions of people around the world each year and its use is increasing in some countries, which makes the need for new, creative, and radical efforts to achieve the tobacco control endgame vitally important. One such effort is discussed in this PLOS Medicine Debate, where Simon Chapman presents his proposal for a "smoker's license" and Jeff Collin argues against. Chapman sets out a case for introducing a smart card license for smokers designed to limit access to tobacco products and encourage cessation. Key elements of the smoker's license include smokers setting daily limits, financial incentives for permanent license surrender, and a test of health risk knowledge for commencing smokers. Collin argues against the proposal, saying that it would shift focus away from the real vector of the epidemic--the tobacco industry--and that by focusing on individuals it would censure victims, increase stigmatization of smokers, and marginalize the poor
Comparative Phylogeography in a Specific and Obligate Pollination Antagonism
In specific and obligate interactions the nature and abundance of a given species can have important effects on the survival and population dynamics of associated organisms. In a phylogeographic framework, we therefore expect that the fates of organisms interacting specifically are also tightly interrelated. Here we investigate such a scenario by analyzing the genetic structures of species interacting in an obligate plant-insect pollination lure-and-trap antagonism, involving Arum maculatum (Araceae) and its specific psychodid (Diptera) visitors Psychoda phalaenoides and Psycha grisescens. Because the interaction is asymmetric (i.e., only the plant depends on the insect), we expect the genetic structure of the plant to be related with the historical pollinator availability, yielding incongruent phylogeographic patterns between the interacting organisms
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