1,182 research outputs found
The Effect of Information on the Bidding and Survival of Entrants in Procurement Auctions
In government procurement auctions of construction contracts, entrants are typically less informed and bid more aggressively than incumbent firms. This bidding behavior makes them more susceptible to losses a¤ecting their prospect of survival. In April of 2000, the Oklahoma Department of Transportation started releasing the internal cost estimates to complete highway construction projects. Using newly developed quantile regression approaches, this paper examines the impact of the policy change on aggressive entrants. First, we find that the information release eliminates the bidding differential between entrants and incumbents attributed to informational asymmetries. Second, we argue that the policy change a¤ects the prospects of survival of entrants in the market. We find that those who used to exit the market relatively soon are now staying 37 percent longer, while at the median level bidding duration increased by roughly 68 percent. The policy has the potential to encourage entry in government procurement auctions and thus increase competition.Entry; Survival; Information Release; Procurement Auctions
Disadvantaged business enterprise goals in government procurement contracting: an analysis of bidding behavior and costs
Programs that encourage the participation of disadvantaged business enterprises (DBE) as subcontractors have been a part of government procurement auctions for over three decades. In this paper, we examine the impact of a program that requires prime contractors to subcontract out a portion of a highway procurement project to DBE firms. We study how DBE subcontracting requirements affect bidding behavior in federally funded projects. Within a symmetric independent private value framework, we use the equilibrium bidding function to obtain the cost distribution of firms undertaking projects either with or without subcontracting goals. We then use nonparametric estimation methodsto uncover and compare the cost of firms bidding on a class of asphalt projects related to surface treatment in Texas. The analysis shows little differences in the cost structure between auctions that have subcontracting goals and those that do not.Auctions ; Government purchasing
About low field memory and negative magnetization in semiconductors and polymers
Ginzburg-Landau bulk magnetization of itinerant electrons can provide a
negative effective field in the Weiss model by coupling to localized magnetic
moments. The coupling enforces remnant magnetization, which can be negative or
positive depending on the sample magnetic history. Stable magnetic
susceptibility of coupled nonequilibrium subsystems with magnetization reversal
is always positive. Gauss-scale fields could be expected for switching between
negative and positive remnant moments in semiconductors with coupling at
ambient temperatures. Negative magnetization in ultra-high conducting polymers
is also discussed within the developed framework.Comment: 8 pages, no figure
Resolving Star Formation on Sub-Kiloparsec Scales in the High-Redshift Galaxy SDP.11 Using Gravitational Lensing
We investigate the properties of the interstellar medium, star formation, and
the current-day stellar population in the strongly-lensed star-forming galaxy
H-ATLAS J091043.1-000321 (SDP.11), at z = 1.7830, using new Herschel and ALMA
observations of far-infrared fine-structure lines of carbon, oxygen and
nitrogen. We report detections of the [O III] 52 um, [N III] 57 um, and [O I]
63 um lines from Herschel/PACS, and present high-resolution imaging of the [C
II] 158 um line, and underlying continuum, using ALMA. We resolve the [C II]
line emission into two spatially-offset Einstein rings, tracing the red- and
blue-velocity components of the line, in the ALMA/Band-9 observations at 0.2"
resolution. The values seen in the [C II]/FIR ratio map, as low as ~ 0.02% at
the peak of the dust continuum, are similar to those of local ULIRGs,
suggesting an intense starburst in this source. This is consistent with the
high intrinsic FIR luminosity (~ 3 x 10^12 Lo), ~ 16 Myr gas depletion
timescale, and < 8 Myr timescale since the last starburst episode, estimated
from the hardness of the UV radiation field. By applying gravitational lensing
models to the visibilities in the uv-plane, we find that the lensing
magnification factor varies by a factor of two across SDP.11, affecting the
observed line profiles. After correcting for the effects of differential
lensing, a symmetric line profile is recovered, suggesting that the starburst
present here may not be the result of a major merger, as is the case for local
ULIRGs, but instead could be powered by star-formation activity spread across a
3-5 kpc rotating disk.Comment: 17 pages, 8 figures, 3 tables, accepted for publication in the
Astrophysical Journa
CO-Dark Star Formation and Black Hole Activity in 3C 368 at z = 1.131: Coeval Growth of Stellar and Supermassive Black Hole Masses
We present the detection of four far-infrared fine-structure oxygen lines, as
well as strong upper limits for the CO(2-1) and [N II] 205 um lines, in 3C 368,
a well-studied radio-loud galaxy at z = 1.131. These new oxygen lines, taken in
conjunction with previously observed neon and carbon fine-structure lines,
suggest a powerful active galactic nucleus (AGN), accompanied by vigorous and
extended star formation. A starburst dominated by O8 stars, with an age of ~6.5
Myr, provides a good fit to the fine-structure line data. This estimated age of
the starburst makes it nearly concurrent with the latest episode of AGN
activity, suggesting a link between the growth of the supermassive black hole
and stellar population in this source. We do not detect the CO(2-1) line, down
to a level twelve times lower than the expected value for star forming
galaxies. This lack of CO line emission is consistent with recent star
formation activity if the star-forming molecular gas has low metallicity, is
highly fractionated (such that CO is photodissociated through much of the
clouds), or is chemically very young (such that CO has not yet had time to
form). It is also possible, though we argue unlikely, that the ensemble of fine
structure lines are emitted from the region heated by the AGN.Comment: 10 pages, 4 figures, 2 tables, accepted for publication in the
Astrophysical Journa
L'aléa tsunami à Wallis et Futuna : modélisation numérique et inventaire des tsunamis (préparé pour l'Administration supérieure du Territoire de Wallis et Futuna)
Biocatalytic preparation and absolute configuration of enantiomerically pure fungistatic anti-2-benzylindane derivatives. Study of the detoxification mechanism by Botrytis cinerea
Enantiomerically pure 2-benzylindane derivatives were prepared using biocatalytic methods and their
absolute configuration determined. (1R,2S)-2-Benzylindan-1-ol ((1R,2S)-2) and
(S)-2-benzylindan-1-one ((S)-3) were produced by fermenting baker’s yeast. Lipase-mediated
esterifications and hydrolysis of the corresponding racemic substrates gave rise to the enantiopure
compounds (1S,2R)-2-benzylindan-1-ol ((1S,2R)-2) and (1R,2S)-2-benzylindan-1-ol ((1R,2S)-2),
respectively. The antifungal activity of these products against two strains of the plant pathogen Botrytis
cinerea was tested. The metabolism of anti-(±)-2-benzylindan-1-ol (anti-(±)-2) by B. cinerea as part of
the fungal detoxification mechanism is also described and revealed interesting differences in the genome
of both strains
Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films
All rights reserved. The origins of spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized d-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a σπ-d exchange analogous to sp-d interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified g-factor of -4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials
Genome-wide transcriptional response of an avian pathogenic Escherichia coli (APEC) pst mutant
<p>Abstract</p> <p>Background</p> <p>Avian pathogenic <it>E</it>. <it>coli </it>(APEC) are associated with extraintestinal diseases in poultry. The <it>pstSCAB</it>-<it>phoU </it>operon belongs to the Pho regulon and encodes the phosphate specific transport (Pst) system. A functional Pst system is required for full virulence in APEC and other bacteria and contributes to resistance of APEC to serum, to cationic antimicrobial peptides and acid shock. The global mechanisms contributing to the attenuation and decreased resistance of the APEC <it>pst </it>mutant to environmental stresses have not been investigated at the transcriptional level. To determine the global effect of a <it>pst </it>mutation on gene expression, we compared the transcriptomes of APEC strain χ7122 and its isogenic <it>pst </it>mutant (K3) grown in phosphate-rich medium.</p> <p>Results</p> <p>Overall, 470 genes were differentially expressed by at least 1.5-fold. Interestingly, the <it>pst </it>mutant not only induced systems involved in phosphate acquisition and metabolism, despite phosphate availability, but also modulated stress response mechanisms. Indeed, transcriptional changes in genes associated with the general stress responses, including the oxidative stress response were among the major differences observed. Accordingly, the K3 strain was less resistant to reactive oxygen species (ROS) than the wild-type strain. In addition, the <it>pst </it>mutant demonstrated reduced expression of genes involved in lipopolysaccharide modifications and coding for cell surface components such as type 1 and F9 fimbriae. Phenotypic tests also established that the <it>pst </it>mutant was impaired in its capacity to produce type 1 fimbriae, as demonstrated by western blotting and agglutination of yeast cells, when compared to wild-type APEC strain χ7122.</p> <p>Conclusion</p> <p>Overall, our data elucidated the effects of a <it>pst </it>mutation on the transcriptional response, and further support the role of the Pho regulon as part of a complex network contributing to phosphate homeostasis, adaptive stress responses, and <it>E. coli </it>virulence.</p
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