2,288 research outputs found
Senecavirus A in Pigs, United States, 2015
Citation: Hause, B. M., Myers, O., Duff, J., & Hesse, R. A. (2016). Senecavirus A in Pigs, United States, 2015. Emerging Infectious Diseases, 22(7), 1323-1325. doi:10.3201/eid2207.151951Senecavirus A (SVA) has been sporadically identified in pigs with idiopathic vesicular disease in the United States and Canada (1–3). Clinical symptoms observed include ruptured vesicles and erosions on the snout and lameness associated with broken vesicles along the coronary band. A recent report characterized SVA in pigs in Brazil with similar clinical symptoms in addition to a higher proportion of deaths than would be expected in pigs 1–4 days of age (4,5). Several outbreaks of this infection in pigs were reported in the summer of 2015 in the United States; the more severe clinical features resembled those seen in outbreaks in Brazil (6). Subsequent testing by PCR of 2,033 oral fluid samples from material submitted during 441 routine diagnostic testing procedures (from 25 states) identified 5 SVA-positive cases (1%) (7). Besides affecting animal health, SVA infection is notable because its clinical symptoms resemble those caused by foot-and-mouth disease and vesicular stomatitis viruses. When vesicular disease is observed in US swine, mandatory reporting and testing of animals for foreign animal diseases are required
Gershgorin disks for multiple eigenvalues of non-negative matrices
Gershgorin's famous circle theorem states that all eigenvalues of a square
matrix lie in disks (called Gershgorin disks) around the diagonal elements.
Here we show that if the matrix entries are non-negative and an eigenvalue has
geometric multiplicity at least two, then this eigenvalue lies in a smaller
disk. The proof uses geometric rearrangement inequalities on sums of higher
dimensional real vectors which is another new result of this paper
Assessment of a sequential phase extraction procedure for uranium-series isotope analysis of soils and sediments
The study of uranium-series (U-series) isotopes in soil and sediment materials has been proposed to quantify rates and timescales of soil production and sediment transport. Previous works have studied bulk soil or sediment material, which is a complex assemblage of primary and secondary minerals and organic compounds. However, the approach relies on the fractionation between U-series isotopes in primary minerals since they were liberated from the parent rock via weathering. In addition, secondary minerals and organic compounds have their own isotopic compositions such that the composition of the bulk material may not reflect that of primary minerals. Hence, there is a need for a sample preparation procedure that allows the isolation of primary minerals in soil or fluvial sediment samples. In this study, a sequential extraction procedure to separate primary minerals from soils and sediments was assessed. The procedure was applied to standard rock sample powders (TML-3 and BCR-2) to test whether it introduced any artefactual radioactive disequilibrium. A new step was introduced to remove the clay-sized fraction (\u3c2 \u3eµm). Significant amounts (5–14%) of U and Th were removed from the rock standards during the procedure. No significant alteration in (234U/238U) and (230Th/238U) activity ratios of the rock standards occurred during the procedure. Aliquots of soil sample were subjected to the sequential extraction process to test how each step modifies the uranium-series activity ratios and mineralogy. Although no secondary minerals were detected in the unleached soil aliquots, the sequential leaching process removed up to 17% of U and Th and modified their activity ratios by up to 3%. The modification of the activity ratios poses a demand for careful means to avoid redistribution of isotopes back to the residual phase during phase extraction
The group law on the tropical Hesse pencil
We show that the addition of points on the tropical Hesse curve can be
realized via the intersection with a tropical line. Then the addition formula
for the tropical Hesse curve is reduced from those for the level-three theta
functions through the ultradiscretization procedure. A tropical analogue of the
Hessian group, the group of linear automorphisms acting on the Hesse pencil, is
also investigated; it is shown that the dihedral group of degree three is the
group of linear automorphisms acting on the tropical Hesse pencil.Comment: 17 pages, 1 figure, submitted to Special Issue of the Journal
Mathematics and Computers in Simulation on "Nonlinear Waves: Computation and
Theory
On the theory of Gordan-Noether on homogeneous forms with zero Hessian (Improved version)
We give a detailed proof for Gordan-Noether's results in "Ueber die
algebraischen Formen, deren Hesse'sche Determinante identisch verschwindet"
published in 1876 in Mathematische Annahlen. C. Lossen has written a paper in a
similar direction as the present paper, but did not provide a proof for every
result. In our paper, every result is proved. Furthermore, our paper is
independent of Lossen's paper and includes a considerable number of new
observations.
An earlier version of this paper has been printed in Proceedings of the
School of Science of Tokai University, Vol.49, Mar. 2014. In this version, a
serious error has been corrected and some new results have been added
On the geometry of C^3/D_27 and del Pezzo surfaces
We clarify some aspects of the geometry of a resolution of the orbifold X =
C3/D_27, the noncompact complex manifold underlying the brane quiver standard
model recently proposed by Verlinde and Wijnholt. We explicitly realize a map
between X and the total space of the canonical bundle over a degree 1 quasi del
Pezzo surface, thus defining a desingularization of X. Our analysis relys
essentially on the relationship existing between the normalizer group of D_27
and the Hessian group and on the study of the behaviour of the Hesse pencil of
plane cubic curves under the quotient.Comment: 23 pages, 5 figures, 2 tables. JHEP style. Added references.
Corrected typos. Revised introduction, results unchanged
INTEGRAL observations of the black hole candidate H 1743-322 in outburst
INTEGRAL made 3 observations in 2003 April of the black hole candidate H
1743-322 during the rising part, and close to the maximum, of an outburst. H
1743-322 was previously observed in outburst in 1977-1978. The source is
located in a crowded region of the sky (l = 357 deg, b = -2 deg) and at least
18 sources are clearly detected in the field of view of the gamma-ray imager
during a 277 ksec exposure. These are well known persistent X-ray binaries and
3 transient sources in outburst. The combined 5-200 keV JEM-X and SPI spectrum
of H 1743-322 is well fit with an absorbed ((2.5 10E22 atom/cm2) soft (photon
index 2.70 +/- 0.09) power-law model consistent with J 1743-322 being in a
high/soft state.Comment: 5 pages. Figs. 2 and 3 are best viewed in color. To appear in
INTEGRAL special edition of A&A
Equianalytic and equisingular families of curves on surfaces
We consider flat families of reduced curves on a smooth surface S such that
each member C has the same number of singularities of fixed singularity types
and the corresponding (locally closed) subscheme H of the Hilbert scheme of S.
We are mainly concerned with analytic resp. topological singularity types and
give a sufficient condition for the smoothness of H (at C). Our results for
S=P^2 seem to be quite sharp for families of cuves of small degree d.Comment: LaTeX v 2.0
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