23,705 research outputs found

    STARLINK: IMPACTS ON THE U.S. CORN MARKET AND WORLD TRADE

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    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.

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    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

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    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

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    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

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    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

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    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 10deg\deg to 60deg\deg. Testing undirectly orbital self-consistency, we search for the main periodic orbits and studied the density response. For pitch angles up to approximately 20deg\sim 20\deg, 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 20deg\sim 20\deg, 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 50deg\sim 50\deg, 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 50deg\sim 50\deg.Comment: ApJL accepted (12 pages, 3 figures

    Maximum relative excitation of a specific vibrational mode via optimum laser pulse duration

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    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

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    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.

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    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
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