327 research outputs found
Bordetella Holmesii-Like Organisms Associated with Septicemia, Endocarditis, and Respiratory Failure
We recovered an unusual bacterial strain from blood or sputum of three patients with septicemia, endocarditis, and/or respiratory failure. The three isolates were thin, curved, gram-negative, light brown, pigment-producing bacilli with variable catalase activity. They were asaccharolytic, oxidasenegative, nonmotile, and fastidious. Identification was not possible on the basis of these characteristics alone or in combination with cellular fatty acid profiles. Nucleic acid amplification and sequence analysis of the 16S rRNA gene revealed that all three isolates were identical and most closely related to the emerging pathogen Bordetella holmesii, diverging from the published sequence at three nucleotide positions (99.8% similarity). Isolation of a B. holmesii-like pathogen from sputum suggests that, in addition to producing septicemia, the organism may inhabit the respiratory tract like other Bordetella species
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Origin of two-band chorus in the radiation belt of Earth.
Naturally occurring chorus emissions are a class of electromagnetic waves found in the space environments of the Earth and other magnetized planets. They play an essential role in accelerating high-energy electrons forming the hazardous radiation belt environment. Chorus typically occurs in two distinct frequency bands separated by a gap. The origin of this two-band structure remains a 50-year old question. Here we report, using NASA's Van Allen Probe measurements, that banded chorus waves are commonly accompanied by two separate anisotropic electron components. Using numerical simulations, we show that the initially excited single-band chorus waves alter the electron distribution immediately via Landau resonance, and suppress the electron anisotropy at medium energies. This naturally divides the electron anisotropy into a low and a high energy components which excite the upper-band and lower-band chorus waves, respectively. This mechanism may also apply to the generation of chorus waves in other magnetized planetary magnetospheres
The Halo Masses of Galaxies to z ∼3: A Hybrid Observational and Theoretical Approach
© 2018. The American Astronomical Society. All rights reserved.. We use a hybrid observational/theoretical approach to study the relation between galaxy kinematics and the derived stellar and halo masses of galaxies up to z =3 as a function of stellar mass, redshift, and morphology. Our observational sample consists of a concatenation of 1125 galaxies with kinematic measurements at 0.4 < z < 3 from long-slit and integral field studies. We investigate several ways to measure halo masses from observations based on results from semi-analytical models, showing that galaxy halo masses can be retrieved with a scatter of ∼0.4 dex by using only stellar masses. We discover a third parameter, relating to the time of the formation of the halo, that reduces the scatter in the relation between the stellar and halo masses such that systems forming earlier have a higher stellar mass-to-halo mass ratio, which we also find observationally. We find that this scatter correlates with morphology such that early-type or older stellar systems have higher M ∗/M halo ratios. We furthermore show, using this approach and through weak lensing and abundance matching, that the ratio of stellar to halo mass does not significantly evolve with redshift at 1 < z < 3. This is evidence for the regulated hierarchical assembly of galaxies such that the ratio of stellar to dark matter mass remains approximately constant since z =2. We use these results to show that the dark matter accretion rate evolves from dM halo/d t ∼4000 yr-1 at z ∼2.5 to a few 100 yr-1 by z ∼0.5
The pneumococcal alpha-glycerophosphate oxidase enhances nasopharyngeal colonization through binding to host glycoconjugates
Streptococcus pneumoniae (the pneumococcus) is a major human pathogen, causing a broad spectrum of diseases including otitis media, pneumonia, bacteraemia and meningitis. Here we examined the role of a potential pneumococcal meningitis vaccine antigen, alpha-glycerophosphate oxidase (SpGlpO), in nasopharyngeal colonization. We found that serotype 4 and serotype 6A strains deficient in SpGlpO have significantly reduced capacity to colonize the nasopharynx of mice, and were significantly defective in adherence to human nasopharyngeal carcinoma cells in vitro. We also demonstrate that intranasal immunization with recombinant SpGlpO significantly protects mice against subsequent nasal colonization by wild type serotype 4 and serotype 6A strains. Furthermore, we show that SpGlpO binds strongly to lacto/neolacto/ganglio host glycan structures containing the GlcNAcβ1-3Galβ disaccharide, suggesting that SpGlpO enhances colonization of the nasopharynx through its binding to host glycoconjugates. We propose that SpGlpO is a promising vaccine candidate against pneumococcal carriage, and warrants inclusion in a multi-component protein vaccine formulation that can provide robust, serotype-independent protection against all forms of pneumococcal disease
Enhanced weathering in the U.S. Corn Belt delivers carbon removal with agronomic benefits
Enhanced weathering (EW) with crushed basalt on farmlands is a promising
scalable atmospheric carbon dioxide removal strategy that urgently requires
performance assessment with commercial farming practices. Our large-scale
replicated EW field trial in the heart of the U.S. Corn Belt shows cumulative
time-integrated carbon sequestration of 15.4 +/- 4.1 t CO2 ha-1 over four
years, with additional emissions mitigation of ~0.1 - 0.4 t CO2,e ha-1 yr-1 for
soil nitrous oxide, a potent long-lived greenhouse gas. Maize and soybean
yields increased 12-16% with EW following improved soil fertility, decreased
soil acidification, and upregulation of root nutrient transport genes. Our
findings suggest that widespread adoption of EW across farming sectors has the
potential to contribute significantly to net-zero greenhouse gas emissions
goals and global food and soil security
Targeted recovery of metals from Thermoelectric Generators (TEGs) using chloride brines and ultrasound
Recovery of elemental copper, bismuth, tellurium, antimony and tin from Thermoelectric Generators (TEGs) is vital to recover the high content of critical metals and potential risk of environmental pollution as a result of incorrect disposal of TEGs and to enable the circular economy. In this work, aqueous choline chloride and calcium chloride hexahydrate brines were characterised and used in combination with copper(II) as an oxidising agent to leach copper and tin from TEGs. This permitted the Bi2-xSbxTe3 legs to readily separated from the ceramic substrates by filtration. It was shown that at low chloride content, surface passivation and solubility of the oxidised species was the limiting factor towards oxidation, whereas solvent viscosity (mass transport) was the limiting factor at high chloride content. The copper(II) species formed in the different brines were determined via UV-vis spectroscopy. The redox potentials of the oxidising species were found to be significantly altered by choline chloride content, but not so much by calcium chloride hexahydrate content, suggesting variation in chloride activity within the different brines. The developed approach has been shown to be a viable and scalable method to recover high value critical metals from e-waste containing TEGs
Quantum dynamics as a physical resource
How useful is a quantum dynamical operation for quantum information
processing? Motivated by this question we investigate several strength measures
quantifying the resources intrinsic to a quantum operation. We develop a
general theory of such strength measures, based on axiomatic considerations
independent of state-based resources. The power of this theory is demonstrated
with applications to quantum communication complexity, quantum computational
complexity, and entanglement generation by unitary operations.Comment: 19 pages, shortened by 3 pages, mainly cosmetic change
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