23,705 research outputs found
STARLINK: IMPACTS ON THE U.S. CORN MARKET AND WORLD TRADE
StarLink disrupted the U.S. corn market during the marketing year of 2000/01 as a result of inadvertent commingling. The potential volume of marketed StarLink-commingled corn from the 2000 crop located in areas near wet and dry millers prior to October 1, 2000, is estimated at 124 million bushels. Price differentials between StarLink-free and StarLink-commingled corn existed during the early stage of the incident, but eroded quickly. While StarLink has had a negative impact on U.S. corn exports, most of the reduction in exports to Japan and South Korea during November 2000 and March 2002 is due to Japan's increased purchases from South Africa, China's decision to continue to subsidize exports, increased competition from the large back-to-back crops in Argentina, and a record Brazilian crop.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
Intersectional Discrimination Is Associated with Housing Instability among Trans Women Living in the San Francisco Bay Area.
Trans women face numerous structural barriers to health due to discrimination. Housing instability is an important structural determinant of poor health outcomes among trans women. The purpose of this study was to determine if experiences of intersectional anti-trans and racial discrimination are associated with poor housing outcomes among trans women in the San Francisco Bay Area. A secondary analysis of baseline data from the Trans *National study (n = 629) at the San Francisco Department of Public Health (2016-2018) was conducted. Multivariable logistic regression was used to analyze the association between discrimination as an ordered categorical variable (zero, one to two, or three or more experiences) and housing status adjusting for age, years lived in the Bay Area, and gender identity. We found that the odds of housing instability increased by 1.25 for every categorical unit increase (1-2, or 3+) in reported experiences of intersectional (both anti-trans and racial) discrimination for trans women (95% CI = 1.01-1.54, p-value < 0.05). Intersectional anti-trans and racial discrimination is associated with increased housing instability among trans women, giving some insight that policies and programs are needed to identify and address racism and anti-trans stigma towards trans women. Efforts to address intersectional discrimination may positively impact housing stability, with potential for ancillary effects on increasing the health and wellness of trans women who face multiple disparities
Tunneling and delocalization in hydrogen bonded systems: a study in position and momentum space
Novel experimental and computational studies have uncovered the proton
momentum distribution in hydrogen bonded systems. In this work, we utilize
recently developed open path integral Car-Parrinello molecular dynamics
methodology in order to study the momentum distribution in phases of high
pressure ice. Some of these phases exhibit symmetric hydrogen bonds and quantum
tunneling. We find that the symmetric hydrogen bonded phase possesses a
narrowed momentum distribution as compared with a covalently bonded phase, in
agreement with recent experimental findings. The signatures of tunneling that
we observe are a narrowed distribution in the low-to-intermediate momentum
region, with a tail that extends to match the result of the covalently bonded
state. The transition to tunneling behavior shows similarity to features
observed in recent experiments performed on confined water. We corroborate our
ice simulations with a study of a particle in a model one-dimensional double
well potential that mimics some of the effects observed in bulk simulations.
The temperature dependence of the momentum distribution in the one-dimensional
model allows for the differentiation between ground state and mixed state
tunneling effects.Comment: 14 pages, 13 figure
On the Mechanical Energy Available to Drive Solar Flares
Where does solar flare energy come from? More specifically, assuming that the
ultimate source of flare energy is mechanical energy in the convection zone,
how is this translated into energy dissipated or stored in the corona? This
question appears to have been given relatively little thought, as attention has
been focussed predominantly on mechanisms for the rapid dissipation of coronal
magnetic energy by way of MHD instabilities and plasma micro instabilities. We
consider three types of flare theory: the steady state "photospheric dynamo"
model in which flare power represents coronal dissipation of currents generated
simultaneously by sub-photospheric flows; the "magnetic energy storage" model
where sub-photospheric flows again induce coronal currents but which in this
case are built up over a longer period before being released suddenly; and
"emerging flux" models, in which new magnetic flux rising to the photosphere
already contains free energy, and does not require subsequent stressing by
photospheric motions. We conclude that photospheric dynamos can power only very
minor flares; that coronal energy storage can in principle meet the
requirements of a major flare, although perhaps not the very largest flares,
but that difficulties in coupling efficiently to the energy source may limit
this mechanism to moderate sized flares; and that emerging magnetic flux tubes,
generated in the solar interior, can carry sufficient free energy to power even
the largest flares ever observed.Comment: 14 pages, 1 figur
Specific Heat of Sr4Ru3O10
We have measured the specific heat of single crystals of the triple-layer
Ruddlesden-Popper material, Sr4Ru3O10, grown both in an image furnace and by
flux-growth. The flux grown sample has a sharp mean-field-like anomaly at the
onset of magnetic order, Tc = 102 K, but a much broader anomaly, indicative of
residual heterogeneity, is observed for the image furnace sample. Even for the
flux grown sample, however, the anomaly is at least an order of magnitude
smaller than one would expect for complete ordering of the spins. Neither
sample exhibits an anomaly at Tm ~ 50 K, where magnetic measurements suggest
that basal plane antiferromagnetism sets in. Anomalous behavior (e.g.
consistent with a term in the specific heat ~ T^3/2 as would be observed for a
three-dimensional ferromagnet with weak exchange) is observed at low
temperatures for both samples, indicative of the unusual magnetic order in this
material.Comment: 14 pages including 4 figure
Pitch Angle Restrictions in Late Type Spiral Galaxies Based on Chaotic and Ordered Orbital Behavior
We built models for low bulge mass spiral galaxies (late type as defined by
the Hubble classification) using a 3-D self-gravitating model for spiral arms,
and analyzed the orbital dynamics as a function of pitch angle, going from
10 to 60. Testing undirectly orbital self-consistency, we search
for the main periodic orbits and studied the density response. For pitch angles
up to approximately , the response supports closely the potential
permitting readily the presence of long lasting spiral structures. The density
response tends to "avoid" larger pitch angles in the potential, by keeping
smaller pitch angles in the corresponding response. Spiral arms with pitch
angles larger than , would not be long-lasting structures but
rather transient. On the other hand, from an extensive orbital study in phase
space, we also find that for late type galaxies with pitch angles larger than
, chaos becomes pervasive destroying the ordered phase space
surrounding the main stable periodic and quasi-periodic orbits and even
destroying them. This result is in good agreement with observations of late
type galaxies, where the maximum observed pitch angle is .Comment: ApJL accepted (12 pages, 3 figures
Maximum relative excitation of a specific vibrational mode via optimum laser pulse duration
For molecules and materials responding to femtosecond-scale optical laser
pulses, we predict maximum relative excitation of a Raman-active vibrational
mode with period T when the pulse has an FWHM duration of 0.42 T. This result
follows from a general analytical model, and is precisely confirmed by detailed
density-functional-based dynamical simulations for C60 and a carbon nanotube,
which include anharmonicity, nonlinearity, no assumptions about the
polarizability tensor, and no averaging over rapid oscillations within the
pulse. The mode specificity is, of course, best at low temperature and for
pulses that are electronically off-resonance, and the energy deposited in any
mode is proportional to the fourth power of the electric field.Comment: 5 pages, 4 figure
Inhibition of interleukin-1 signaling enhances elimination of tyrosine kinase inhibitor treated CML stem cells
Treatment of chronic myelogenous leukemia (CML) with BCR-ABL tyrosine kinase inhibitors
(TKI) fails to eliminate leukemia stem cells (LSC). Patients remain at risk for relapse, and
additional approaches to deplete CML LSC are needed to enhance the possibility of
discontinuing TKI treatment. We have previously reported that expression of the pivotal proinflammatory
cytokine interleukin-1 (IL-1) is increased in CML bone marrow (BM). We show
here that CML LSC demonstrated increased expression of the IL-1 receptors, IL-1RAP and IL-
1R1, and enhanced sensitivity to IL-1-induced NF-KB signaling compared to normal stem cells.
Treatment with recombinant IL-1 receptor antagonist (IL-1RA) inhibited IL-1 signaling in CML
LSC and inhibited growth of CML LSC. Importantly, the combination of IL-1RA with TKI resulted
in significantly greater inhibition of CML LSC compared with TKI alone. Our studies also suggest
that IL-1 signaling contributes to overexpression of inflammatory mediators in CML LSC,
suggesting that blocking IL-1 signaling could modulate the inflammatory milieu. We conclude
that IL-1 signaling contributes to maintenance of CML LSC following TKI treatment, and that IL-
1 blockade with IL-1RA enhances elimination of TKI-treated CML LSC. These results provide a
strong rationale for further exploration of anti-IL-1 strategies to enhance LSC elimination in CML
Integrated Regulatory and Metabolic Networks of the Marine Diatom Phaeodactylum tricornutum Predict the Response to Rising CO2 Levels.
Diatoms are eukaryotic microalgae that are responsible for up to 40% of the ocean's primary productivity. How diatoms respond to environmental perturbations such as elevated carbon concentrations in the atmosphere is currently poorly understood. We developed a transcriptional regulatory network based on various transcriptome sequencing expression libraries for different environmental responses to gain insight into the marine diatom's metabolic and regulatory interactions and provide a comprehensive framework of responses to increasing atmospheric carbon levels. This transcriptional regulatory network was integrated with a recently published genome-scale metabolic model of Phaeodactylum tricornutum to explore the connectivity of the regulatory network and shared metabolites. The integrated regulatory and metabolic model revealed highly connected modules within carbon and nitrogen metabolism. P. tricornutum's response to rising carbon levels was analyzed by using the recent genome-scale metabolic model with cross comparison to experimental manipulations of carbon dioxide. IMPORTANCE Using a systems biology approach, we studied the response of the marine diatom Phaeodactylum tricornutum to changing atmospheric carbon concentrations on an ocean-wide scale. By integrating an available genome-scale metabolic model and a newly developed transcriptional regulatory network inferred from transcriptome sequencing expression data, we demonstrate that carbon metabolism and nitrogen metabolism are strongly connected and the genes involved are coregulated in this model diatom. These tight regulatory constraints could play a major role during the adaptation of P. tricornutum to increasing carbon levels. The transcriptional regulatory network developed can be further used to study the effects of different environmental perturbations on P. tricornutum's metabolism
- …
