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Full-Text Articles in Physical Sciences and Mathematics
Neutron-Irradiation Effects On The V-I Characteristics Of Yba2cu3o7-Δ Twinned Crystals:Linking Transport Results In A Variety Of Copper Oxide Superconductors, Brandon R. Brown
Neutron-Irradiation Effects On The V-I Characteristics Of Yba2cu3o7-Δ Twinned Crystals:Linking Transport Results In A Variety Of Copper Oxide Superconductors, Brandon R. Brown
Physics and Astronomy
We have investigated the depinning process of magnetic flux vortices in twinned crystals of YBa2Cu3O7-δ in intermediate applied magnetic fields parallel to the crystallographic c axis through precise resistivity measurements before and after fast-neutron irradiation. Of particular interest for each field is the power-law dependence of the electric field on current density, E∝Jn, at a well defined temperature which separates a nonlinear region below from a more linear, dissipative region above. We find that n shows a striking dependence on the estimated value of the Larkin-Ovchinnikov length. The relation is not only manifest …
Detecting Fire And Grazing Patterns In Tallgrass Prairie Using Spectral Mixture Analysis, Carol A. Wessman, C Ann Bateson, Tracy Benning
Detecting Fire And Grazing Patterns In Tallgrass Prairie Using Spectral Mixture Analysis, Carol A. Wessman, C Ann Bateson, Tracy Benning
Environmental Science
Global grasslands are typically under management practices (such as fire and grazing) that alter nutrient cycling, ecosystem composition, and distribution of organic matter from the unmanaged condition. We evaluated landscape-level response to fire and grazing treatments in the Konza Tallgrass Prairie Research Natural Area, Kansas, using spectral mixture analysis of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired 31 August 1990. Spectral mixture analysis derives the fractional abundances of spectrally unique components in the landscape. The reflectance spectra of these components are called endmembers. Endmember fractions values were compared against ground values of live biomass, current standing dead biomass, and litter …
Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella
Identification Of The Adp-L-Glycero-D-Manno-Heptose-6-Epimerase (Rfad) And Heptosyltransferase Ii (Rfaf) Biosynthesis Genes From Nontypeable Haemophilus Influenzae 2019, W A. Nichols, B W. Gibson, William Melaugh, N G. Lee, M Sunshine, M A. Apicella
Chemistry Faculty Publications
Haemophilus influenzae is an important human pathogen. The lipooligosaccharide (LOS) of H. influenzae has been implicated as a virulence determinant. To better understand the assembly of LOS in nontypeable H. influenzae (NtHi), we have cloned and characterized the rfaD and rfaF genes of NtHi 2019, which encode the ADP-L-glycero-D-manno-heptose-6-epimerase and heptosyltransferase II enzymes, respectively. This cloning was accomplished by the complementation of Salmonella typhimurium lipopolysaccharide (LPS) biosynthesis gene mutants. These deep rough mutants are novobiocin susceptible until complemented with the appropriate gene. In this manner, we are able to use novobiocin resistance to select for specific NtHi LOS inner core …
Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson
Characterization Of A Transposon Tn916-Generated Mutant Of Haemophilus Ducreyi 35000 Defective In Lipooligosaccharide Biosynthesis, B W. Gibson, A A. Campagnari, William Melaugh, M A. Apicella, S Grass, Jing Wang, Katherine L. Palmer, R S. Munson
Chemistry Faculty Publications
To define the role of the surface lipooligosaccharide (LOS) of Haemophilus ducreyi in the pathogenesis of chancroid, Tn916 mutants of H. ducreyi 35000 defective in expression of the murine monoclonal antibody (MAb) 3F11 epitope on H. ducreyi LOS were identified by immunologic screening. One mutant, designated 1381, has an LOS which lacks the MAb 3F11 epitope and migrates with an increased mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gene disrupted by the Tn916 element in strain 1381 was identified by cloning the sequences flanking the Tn916 element. The sequences were then used to probe a lambda DASHII genomic library. …
Constraints On The Production Of Ultra–High-Energy Cosmic Rays By Isolated Neutron Stars, Aparna Venkatesan, M Coleman Miller, Angela V. Olinto
Constraints On The Production Of Ultra–High-Energy Cosmic Rays By Isolated Neutron Stars, Aparna Venkatesan, M Coleman Miller, Angela V. Olinto
Physics and Astronomy
The energetics, spectrum, and composition of cosmic rays with energies below ~1015 eV are fairly well explained by models involving supernova shocks. In contrast, no widely accepted theory exists for the origin of ultra-high-energy cosmic rays (UHECRs), which have energies above 1015 eV. Instead of proposing a specific model, here we place strong constraints on any model of UHECRs involving isolated neutron stars (no companions). We consider the total power requirements and show that the only viable power source associated with isolated neutron stars is rotation. Mechanisms based on accretion from the interstellar medium fall short of the …