290 research outputs found
Specific wavelength colorimeter
A self contained, specific wavelength, single beam colorimeter is described for direct spectrophotometric measurement of the concentration of a given solute in a test sample. An electrical circuit employing a photoconductive cell converts the optical output into a linear, directly readable meter output. The colorimeter is simple to operate and is adapted for use in zero gravity conditions. In a specific application, the colorimeter is designed to analyze the concentration of iodine in potable water carried aboard a space vehicle such as the 4B stage of Skylab
Screening Eucalyptus cloeziana and E. argophloia populations for resistance to Puccinia psidii
Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations.
Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations
Screening Eucalyptus cloeziana and E. argophloia populations for resistance to Puccinia psidii
Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations.
Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations
Lung cancer screening in 2008: A review and update
SummaryThis article discusses the strengths and weaknesses of using sputum cytology, plain chest radiograph and computerized tomography (CT) as screening modalities for lung cancer and provides recommendations for screening
Vortices and Quantum tunneling in Current-Biased 0-\pi-0 Josephson Junctions of d-wave Superconductors
We study a current-biased 0-\pi-0 Josephson junction made by high-T_c
superconductors, theoretically. When a length of the \pi junction is large
enough, this junction contains a vortex-antivortex pair at both ends of the \pi
junction. Magnetic flux carried by the vortices is calculated using the
sine-Gordon equation. The result shows that the magnetic flux of the vortices
is suppressed to zero as the distance between the vortices is reduced. By
applying an external current, the orientation of the vortices is reversed, and
a voltage pulse is generated. The current needed for this transition and
generated pulse energy are calculated. Macroscopic quantum tunneling (MQT) in
this transition is also studied. The tunneling rate has been evaluated by an
effective Hamiltonian with one degree of freedom.Comment: 12 pages, LaTeX with 5 PS figures, using jpsj.st
Macroscopic Symmetry Group Describes Josephson Tunneling in Twinned Crystals
A macroscopic symmetry group describing the superconducting state of an
orthorhombically twinned crystal of YBCO is introduced. This macroscopic
symmetry group is different for different symmetries of twin boundaries.
Josephson tunneling experiments performed on twinned crystals of YBCO determine
this macroscopic symmetry group and hence determine the twin boundary symmetry
(but do not experimentally determine whether the microscopic order parameter is
primarily d- or s-wave). A consequence of the odd-symmetry twin boundaries in
YBCO is the stability of vortices containing one half an elementary flux
quantum at the intersection of a twin boundary and certain grain boundaries.Comment: 6 pages, to be published in the Proceedings of the MOS96 Conference
in the Journal of Low Temperature Physic
Orthorhombically Mixed s and d Wave Superconductivity and Josephson Tunneling
The effect of orthorhombicity on Josephson tunneling in high T
superconductors such as YBCO is studied for both single crystals and highly
twinned crystals. It is shown that experiments on highly twinned crystals
experimentally determine the symmetry of the superconducting twin boundaries
(which can be either even or odd with respect to a reflection in the twinning
plane). Conversely, Josephson experiments on highly twinned crystals can not
experimentally determine whether the superconductivity is predominantly
-wave or predominantly -wave. The direct experimental determination of
the order-parameter symmetry by Josephson tunneling in YBCO thus comes from the
relatively few experiments which have been carried out on untwinned single
crystals.Comment: 5 pages, RevTeX file, 1 figure available on request
([email protected]
Flux-flow in d-wave superconductors: Low temperature universality and scaling
We demonstrate that superclean d-wave superconductors display a novel type of
vortex dynamics: At low temperatures, both dissipative and transverse
components of the flux-flow conductivity are found to approach universal values
even in the limit of infinite relaxation time. A finite dissipation in the
superclean limit is explained in terms of the Landau damping on zero-frequency
vortex modes which appear due to minigap nodes in the bound-state spectrum in
the vortex core. In the moderately clean regime the scaling law at low T and
low field is obtained.Comment: RevTex file, 4 pages, no figures, submitted to Phys. Rev. Lett.,
revised after referee report
Mesoscopic Superconducting Disc with Short-Range Columnar Defects
Short-range columnar defects essentially influence the magnetic properties of
a mesoscopic superconducting disc.They help the penetration of vortices into
the sample, thereby decrease the sample magnetization and reduce the upper
critical field. Even the presence of weak defects split a giant vortex state
(usually appearing in a clean disc in the vicinity of the transition to a
normal state) into a number of vortices with smaller topological charges. In a
disc with a sufficient number of strong enough defects vortices are always
placed onto defects. The presence of defects lead to the appearance of
additional magnetization jumps related to the redistribution of vortices which
are already present on the defects and not to the penetration of new vortices.Comment: 14 pgs. RevTex, typos and figures corrected. Submitted to Phys. Rev.
Phenomenological BCS theory of the high- cuprates
A BCS model characterized by a phenomenological pair potential with on-site
(), nearest (), and next nearest () neighbour coupling
constants, and an empirical quasiparticle dispersion taken from angle-resolved
photoemission spectra is considered. The model can consistently explain the
experimental data concerning the pair state of the hole doped cuprates. Three
ingredients are required to make the interpretation possible: the existence of
flat bands, a very small effective on-site repulsion, and a slightly dominating
effective nnn attraction of the order of 60-80meV with a ratio .Comment: 13 pages, uuencoded Postscrip
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