483 research outputs found
A new chemistry for managing soybean aphid
Since the arrival of soybean aphid, Aphis glycines Matsumura, to North America, entomologists have generated considerable research to effectively protect yield in soybean, Glycine max (L.). Population dynamics of this relatively new pest have been erratic between fields and among years, and timely insecticide applications must be used to prevent severe economic loss
Using bacterial biomarkers to identify early indicators of cystic fibrosis pulmonary exacerbation onset
Acute periods of pulmonary exacerbation are the single most important cause of morbidity in cystic fibrosis patients, and may be associated with a loss of lung function. Intervening prior to the onset of a substantially increased inflammatory response may limit the associated damage to the airways. While a number of biomarker assays based on inflammatory markers have been developed, providing useful and important measures of disease during these periods, such factors are typically only elevated once the process of exacerbation has been initiated. Identifying biomarkers that can predict the onset of pulmonary exacerbation at an early stage would provide an opportunity to intervene before the establishment of a substantial immune response, with major implications for the advancement of cystic fibrosis care. The precise triggers of pulmonary exacerbation remain to be determined; however, the majority of models relate to the activity of microbes present in the patient's lower airways of cystic fibrosis. Advances in diagnostic microbiology now allow for the examination of these complex systems at a level likely to identify factors on which biomarker assays can be based. In this article, we discuss key considerations in the design and testing of assays that could predict pulmonary exacerbations
Two Exoplanets Discovered at Keck Observatory
We present two exoplanets detected at Keck Observatory. HD 179079 is a G5
subgiant that hosts a hot Neptune planet with Msini = 27.5 M_earth in a 14.48
d, low-eccentricity orbit. The stellar reflex velocity induced by this planet
has a semiamplitude of K = 6.6 m/s. HD 73534 is a G5 subgiant with a
Jupiter-like planet of Msini = 1.1 M_jup and K = 16 m/s in a nearly circular
4.85 yr orbit. Both stars are chromospherically inactive and metal-rich. We
discuss a known, classical bias in measuring eccentricities for orbits with
velocity semiamplitudes, K, comparable to the radial velocity uncertainties.
For exoplanets with periods longer than 10 days, the observed exoplanet
eccentricity distribution is nearly flat for large amplitude systems (K > 80
m/s), but rises linearly toward low eccentricity for lower amplitude systems (K
> 20 m/s).Comment: 8 figures, 6 tables, accepted, Ap
Five planets and an independent confirmation of HD 196885Ab from Lick Observatory
We present time series Doppler data from Lick Observatory that reveal the
presence of long-period planetary companions orbiting nearby stars. The typical
eccentricity of these massive planets are greater than the mean eccentricity of
known exoplanets. HD30562b has Msini = 1.29 Mjup, with semi-major axis of 2.3
AU and eccentricity 0.76. The host star has a spectral type F8V and is metal
rich. HD86264b has Msini = 7.0 Mjup, arel = 2.86 AU, an eccentricity, e = 0.7
and orbits a metal-rich, F7V star. HD87883b has Msini = 1.78 Mjup, arel = 3.6
AU, e = 0.53 and orbits a metal-rich K0V star. HD89307b has Msini = 1.78 Mjup,
arel = 3.3 AU, e = 0.24 and orbits a G0V star with slightly subsolar
metallicity. HD148427b has Msini = 0.96 Mjup, arel = 0.93 AU, eccentricity of
0.16 and orbits a metal rich K0 subgiant. We also present velocities for a
planet orbiting the F8V metal-rich binary star, HD196885A. The planet has Msini
= 2.58 Mjup, arel = 2.37 AU, and orbital eccentricity of 0.48, in agreement
with the independent discovery by Correia et al. 2008.Comment: 12 figures, 8 tables, accepted Ap
Dietary Iron Deficiency Impaired Peripheral Immunity but Did Not Alter Brain Microglia in PRRSV-Infected Neonatal Piglets
During the postnatal period the developing brain is vulnerable to insults including nutrient insufficiency and infection that may lead to disrupted development and cognitive dysfunction. Since iron deficiency (ID) often presents with immunodeficiency, the objective of this study was to investigate peripheral viremia and inflammation as well as brain microglial phenotype and function when ID and respiratory infection occur simultaneously in a neonatal piglet model. On postnatal day 2 (PD 2) male and female piglets were assigned to one of four treatments and fed either control or ID milk replacer. On PD 8 half the pigs on each diet were inoculated with either vehicle or porcine reproductive and respiratory syndrome virus (PRRSV; P-129). Blood samples were collected prior to inoculation (PD 7) and repeated once weekly. Rectal temperature, feeding score, and sickness behavior were measured daily until PD 28. Hematocrit, hemoglobin, and serum iron were reduced by ID but not PRRSV infection. PRRSV-infected piglets displayed viremia by PD 14; however, those fed control diet had lower viral titer on PD 28, while circulating virus remained elevated in those fed an ID diet, suggesting that ID either impaired immune function necessary for viral clearance or increased viral replication. ID piglets infected with PRRSV displayed reduced sickness behavior compared to those fed control diet on PD 13-15 and 18-20. While ID piglet sickness behavior progressively worsened, piglets fed control diet displayed improved sickness score after PD 21. Microglia isolated from PRRSV piglets had increased MHCII expression and phagocytic activity ex vivo compared to uninfected piglets. ID did not alter microglial activation or phagocytic activity. Similarly, microglial cytokine expression was increased by PRRSV but unaffected by ID, in stark contrast to peripheral blood mononuclear cell (PBMC) cytokine expression, which was increased by infection and generally decreased by ID. Taken together, these data suggest that ID decreases peripheral immune function leading to increased viremia, but immune activity in the brain is protected from acute ID
Se Isotopes as Groundwater Redox Indicators:Detecting Natural Attenuation of Se at an in Situ Recovery U Mine
One
of the major ecological concerns associated with the in situ
recovery (ISR) of uranium (U) is the environmental release of soluble,
toxic selenium (Se) oxyanions generated by mining. Post-mining natural
attenuation by the residual reductants in the ore body and reduced
down-gradient sediments should mitigate the risk of Se contamination
in groundwater. In this work, we investigate the Se concentrations
and Se isotope systematics of groundwater and of U ore bearing sediments
from an ISR site at Rosita, TX, USA. Our results show that selenate
(SeΒ(VI)) is the dominant Se species in Rosita groundwater, and while
several up-gradient wells have elevated SeΒ(VI), the majority of the
ore zone and down-gradient wells have little or no Se oxyanions. In
addition, the Ξ΄<sup>82</sup>Se<sub>VI</sub> of Rosita groundwater
is generally elevated relative to the U ore up to +6.14β°, with
the most enriched values observed in the ore-zone wells. Increasing
Ξ΄<sup>82</sup>Se with decreasing SeΒ(VI) conforms to a Rayleigh
type distillation model with an Ξ΅ of β2.25β° Β±
0.61β°, suggesting natural SeΒ(VI) reduction occurring along
the hydraulic gradient at the Rosita ISR site. Furthermore, our results
show that Se isotopes are excellent sensors for detecting and monitoring
post-mining natural attenuation of Se oxyanions at ISR sites
Opportunity rover localization and topographic mapping at the landing site of Meridiani Planum, Mars
This paper presents the results of Mars topographic mapping and lander and rover localization for the Opportunity rover at Meridiani Planum during the Mars Exploration Rover (MER) 2003 mission. By Sol 458, the Opportunity rover traversed a distance of 5.20 km. We localized the lander using two-way Doppler radio positioning and cartographic triangulation of craters visible in both orbital and ground images. Additional high-resolution orbital images were taken to verify the determined lander position. Visual odometry and bundle adjustment techniques were applied to overcome wheel slippages, azimuthal angle drift, and other navigation errors (as large as 21% within Eagle crater). In addition, orbit-to-ground image-based adjustment was applied to correct rover location errors where bundle adjustment was not applicable. We generated timely topographic products, including orthoimages, digital terrain models (DTMs), three-dimensional (3-D) crater models, and rover traverse maps. In particular, detailed 3-D terrain models of major features, such as Endurance crater, have been generated using multisite panoramic stereo images based on bundle adjustment and wide baseline stereo technique
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