2,953 research outputs found
IMPLICATIONS OF FUEL SHORTAGES ON COTTON AND GRAIN SORGHUM PRODUCTION AND PRODUCER RETURNS -- SOUTHERN HIGH PLAINS OF TEXAS
Crop Production/Industries,
ESTIMATING REGIONAL OUTPUT RESPONSE TO AN EXHAUSTIBLE NATURAL RESOURCE
Resource /Energy Economics and Policy,
An American approach to anaesthesia research and a British perspective
The organisation of research in the Department of Anesthesiology at the University of Michigan is described and the comments of a British Senior Registrar working within the system are recorded.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74028/1/j.1365-2044.1981.tb08682.x.pd
REGIONAL IMPACT OF URBAN WATER USE ON IRRIGATED AGRICULTURE
Linear programming and regional input-output models were applied to estimate the impacts of increased pumping costs for irrigated agriculture due to groundwater depletion principally caused by the expanding urban area of San Antonio, Texas. A biophysical simulator was use to estimate linear programming coefficients of crop yield by irrigation level and timing. The results indicated significant local (county) economic impacts from groundwater mining but insignificant regional impacts. A major improvement on irrigation efficiency would be required to offset the increased pumping costs and reduce water availability associated with increased lifts due to urban expansion.Resource /Energy Economics and Policy,
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Electronic data interchange: If A perspective from Taiwan
This study presents findings about perceptions and use of Electronic Data Interchange (EDI) in Taiwan. It was undertaken to help build a framework within which to better understand EDI in a global setting. Findings indicate that there are differences and similarities between perceptions and use of EDI in Taiwan and what we know about EDI use in Western cultures. Possible explanations are offered for these findings. Several research questions arise out of the findings that can guide future research about EDI in a variety of cultures, and sets of propositions for each research question are suggested
Spa47 is an oligomerization-activated type three secretion system (T3SS) ATPase from \u3cem\u3eShigella flexneri\u3c/em\u3e
Gram-negative pathogens often use conserved type three secretion systems (T3SS) for virulence. The Shigella type three secretion apparatus (T3SA) penetrates the host cell membrane and provides a unidirectional conduit for injection of effectors into host cells. The protein Spa47 localizes to the base of the apparatus and is speculated to be an ATPase that provides the energy for T3SA formation and secretion. Here, we developed an expression and purification protocol, producing active Spa47 and providing the first direct evidence that Spa47 is a bona fide ATPase. Additionally, size exclusion chromatography and analytical ultracentrifugation identified multiple oligomeric species of Spa47 with the largest greater than 8 fold more active for ATP hydrolysis than the monomer. An ATPase inactive Spa47 point mutant was then engineered by targeting a conserved Lysine within the predicted Walker A motif of Spa47. Interestingly, the mutant maintained a similar oligomerization pattern as active Spa47, but was unable to restore invasion phenotype when used to complement a spa47 null S. flexneri strain. Together, these results identify Spa47 as a Shigella T3SS ATPase and suggest that its activity is linked to oligomerization, perhaps as a regulatory mechanism as seen in some related pathogens. Additionally, Spa47 catalyzed ATP hydrolysis appears to be essential for host cell invasion, providing a strong platform for additional studies dissecting its role in virulence and providing an attractive target for anti-infective agents
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Association of Systemic Inflammation With Retinal Vascular Caliber in Patients With AIDS.
PurposeTo evaluate relationships among retinal vascular caliber and biomarkers of systemic inflammation in patients with AIDS.MethodsA total of 454 participants with AIDS had retinal vascular caliber (central retinal artery equivalent and central retinal vein equivalent) determined from enrollment retinal photographs by reading center graders masked to clinical and biomarker information. Cryopreserved plasma specimens were assayed for inflammatory biomarkers, including C-reactive protein (CRP), IL-6, interferon-γ inducible protein (IP)-10, kynurenine/tryptophan (KT) ratio, and intestinal fatty acid binding protein (I-FABP).ResultsIn the simple linear regression of retinal vascular caliber on plasma biomarkers, elevated CRP, IL-6, and IP-10 were associated with retinal venular dilation, and elevated KT ratio with retinal arteriolar narrowing. In the multiple linear regression, including baseline characteristics and plasma biomarkers, AMD was associated with dilation of retinal arterioles (mean difference: 9.1 μm; 95% confidence interval [CI] 5.2, 12.9; P < 0.001) and venules (mean difference, 10.9 μm; 95% CI, 5.3, 16.6; P < 0.001), as was black race (P < 0.001). Hyperlipidemia was associated with retinal venular narrowing (mean difference, -7.5 μm; 95% CI, -13.7, -1.2; P = 0.02); cardiovascular disease with arteriolar narrowing (mean difference, -5.2 μm; 95% CI, -10.3, -0.1; P = 0.05); age with arteriolar narrowing (slope, -0.26 μm/year; 95% CI, -0.46, -0.06; P = 0.009); and IL-6 with venular dilation (slope, 5.3 μm/standard deviation log10[plasma IL-6 concentration]; 95% CI, 2.7, 8.0; P < 0.001).ConclusionsThese data suggest that retinal vascular caliber is associated with age, race, AMD, hyperlipidemia, cardiovascular disease, and selected biomarkers of systemic inflammation
Balmer-dominated shocks in Tycho's SNR: omnipresence of CRs
We present wide-field, spatially and highly resolved spectroscopic
observations of Balmer filaments in the northeastern rim of Tycho's supernova
remnant in order to investigate the signal of cosmic-ray (CR) acceleration. The
spectra of Balmer-dominated shocks (BDSs) have characteristic narrow (FWHM
10 kms) and broad (FWHM 1000 kms) H
components. CRs affect the H-line parameters: heating the cold neutrals
in the interstellar medium results in broadening of the narrow H-line
width beyond 20 kms, but also in reduction of the broad H-line
width due to energy being removed from the protons in the post-shock region.
For the first time we show that the width of the narrow H line, much
larger than 20 kms, is not a resolution or geometric effect nor a
spurious result of a neglected intermediate (FWHM 100 kms)
component resulting from hydrogen atoms undergoing charge exchange with warm
protons in the broad-neutral precursor. Moreover, we show that a narrow line
width 20 kms extends across the entire NE rim, implying CR
acceleration is ubiquitous, and making it possible to relate its strength to
locally varying shock conditions. Finally, we find several locations along the
rim, where spectra are significantly better explained (based on Bayesian
evidence) by inclusion of the intermediate component, with a width of 180
kms on average.Comment: Proceeding for contributed talk at the IAU Symposium No. 331: "SN
1987A, 30 years later - Cosmic Rays and Nuclei from Supernovae and their
Aftermaths", 2017, La Reunion Island; References correcte
Balmer filaments in Tycho's supernova remnant: an interplay between cosmic-ray and broad-neutral precursors
We present H spectroscopic observations and detailed modelling of the
Balmer filaments in the supernova remnant Tycho. We used Galaxy H
Fabry-P\'erot Spectrometer on the William Herschel Telescope with a
3.4'3.4' field-of-view, 0.2" pixel scale and \sigma_\rm{instr}=8.1
km/s resolution at 1" seeing for hours, resulting in 82
spatial-spectral bins that resolve the narrow H line in the entire
Tycho's northeastern rim. For the first time, we can mitigate artificial line
broadening from unresolved differential motion, and probe H emission
parameters in varying shock and ambient medium conditions. Broad H line
remains unresolved within spectral coverage of 392 km/s. We employed Bayesian
inference to obtain reliable parameter confidence intervals, and quantify the
evidence for models with multiple line components. The median H
narrow-line full-width at half-maximum of all bins and models is
W_\rm{NL}=(54.8\pm1.8) km/s at the confidence level, varying within
[35, 72] km/s between bins and clearly broadened compared to the intrinsic
(thermal) km/s. Possible line splits are accounted for, significant
in of the filament, and presumably due to remaining projection
effects. We also find wide-spread evidence for intermediate-line emission of a
broad-neutral precursor, with median W_\rm{IL}=(180\pm14) km/s (
confidence). Finally, we present a measurement of the remnant's systemic
velocity, V_\rm{LSR}=-34 km/s, and map differential line-of-sight motions.
Our results confirm the existence and interplay of shock precursors in Tycho's
remnant. In particular, we show that suprathermal narrow-line emission is
near-universal in Tycho and that, in absence of an alternative explanation,
collisionless supernova remnant shocks constitute a viable acceleration source
for Galactic TeV Cosmic-Ray protons.Comment: 36 pages, 17 figures, 5 tables, Paper accepted for publication in the
Astrophysical Journal; References correcte
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