1,628 research outputs found
Hermitian Symmetric Matrices, the Schur-Horn Theorem, and Constructibility
No full textA theorem first published in 1923 by Schur showed how the diagonal\ud
elements of a Hermitian symmetric matrix are related to its eigenvalues.\ud
Thirty-one years later, the converse was proved by Horn, and together\ud
these results became known as the Schur-Horn Theorem for Hermitian\ud
symmetric matrices. In this paper, we present novel proofs (due to S.F.\ud
Singer and the author) of both directions of this theorem. The proof\ud
of Horn's Theorem gives a new algorithm for explicitly constructing a\ud
Hermitian symmetric matrix with a determined diagonal from a point in\ud
the convex hull of the set of permutations of a set of eigenvalues
Reconciling astrochronological and 40Ar/39Ar ages for the Matuyama-Brunhes boundary and late Matuyama Chron
No full textWhen five Matuyama-Brunhes (M-B) boundary records from the North Atlantic are placed on isotope age models, produced by correlation of the ?18O record directly or indirectly to an ice volume model, the M-B boundary lies consistently at the young end of marine isotope stage 19 with a mean age for the midpoint of the reversal of 773.1 ka (standard deviation = 0.4 kyr), ?7 kyr younger than the presently accepted astrochronological age for this polarity reversal (780–781 ka). Two recently proposed revisions of the age of the 40Ar/39Ar Fish Canyon sanidine (FCs) standard to 28.201 ± 0.046 Ma and 28.305 ± 0.036 Ma would adjust 40Ar/39Ar ages applicable to the M-B boundary (and other reversals and excursions back to 1.2 Ma) to ages older than the new astrochronological ages by 8–24 kyr. The variables used to construct the ice volume models cannot account for the discrepancy. The FCs standard age that best fits the astrochronological ages is 27.93 Ma, which is within the uncertainty associated with the commonly used value of 28.02 (±0.16) Ma but younger than the recently proposed FCs ages. The EDC2 and EDC3 age models in the Dome C (Antarctic) ice core yield ages of 771.7 ka and 766.4 ka, respectively, for the 10Be flux peak that denotes the paleointensity minimum at the reversal boundary, implying that the EDC2 (rather than EDC3) age model is consistent with the observations from marine sediments, at least close to the M-B boundary
Conference papers of Barc Scientists and engineers : a citation based study
No full textThis paper highlights the importance of conference papers in the scientific communication process. Carried out a citation analysis of 474 (8.52%) conference papers of BARC Scientists and Engineers published during 1999-2007 as per Scopus database. The highest number of papers (117) were published in 2004 and these papers have received the highest (183) number of citations. The average number of papers published per year was 52.66 and the average number of citations per paper was 1.81. Identified highly cited authors and highly cited conference papers. Concludes that conference literature has to be integrated with the databases so as to avoid the missing link in the knowledge development process
BONDEFRIHED OG ANDRE VERDENSBILLEDER IDEHISTORISKE STUDIER AF B.S. INGEMANNS DANMARKSHISTORIE 1824-1836
No full textABSTRACTPeasants’ Freedom and other Ideas of History:Studies in the Historical Literature of B.S. Ingemann 1824-1836Using a New Historicist approach this article examines four worldviews imbedded in a reading of B.S. Ingemanns historical literature which was published between 1824-1836 in the genre of two poems and four historical novels. The worldview of the author-subject (1), a worldview related to the relationship between the monarchy and the people, largely conceived within the so called ‘myth of an original peasants freedom’, a founding myth within Danish historiography (2), a worldview related to the defense of the Danish version of monarchism, in particular the thoughts put forward by the Danish lawyer Jacob Mandix (3), and finally a worldview related to notions of the ideal ‘Rechtsstat’, where Ingemanns literature is read within the context of the discipline “Law and Literature” (4). The article displays personal experiences with monarchism which becomes the primary object of investigation in the context of empirical analysis of prose fiction
Kandel, Phoebe M., B.S. A.M.
No full textPhoebe Kandel was born in Greentown, Ohio in 1882. Ms Kandel received her diploma from Canton Actual Business College and was a graduate of the Lakeside Hospital Training School for Nurses (now the Frances Bolton School of Nursing, Case Western Reserve University) in 1908. Ms Kandel received her both her B.S. (1923) and A.M. (1934) from The Teachers College, Columbia University. Ms Kandel was an Instructor at the Jewish Hospital School of Nursing, Cincinnati, Ohio from 1916-1918; Superintendent of City Hospital, Springfield, Ohio 1918 and Instructor of Nursing at the University of Cincinnati (1919-1924) and Director and Associate Professor of Nursing (1924-1926). Ms Kandel was State Director of Nursing Education for Nebraska from 1928-1930. Ms Kandel was Professor and Director of Nursing Education at Colorado State College, Greeley from 1930-1941. Ms Kandel came to the University as Professor of and Director of Nursing Education (1941-1943). Ms Kandel was later associated with the University of Georgia (1944-1949) and with the Mississippi State Board of Nurses Examiners and Registration (1949). Ms. Kandel was the author of the books, From Mud to Crystal (1923) and Hospital Economics for Nurses (1930). Phoebe Kandel died in 1982
Revised ages of blueschist metamorphism and the youngest pre-thrusting rocks in the San Juan Islands, Washington
No full textNew ages of rocks in the San Juan Islands (SJI), northwest Washington, significantly change our understanding of the evolution of the SJI thrust system. Re-examination of foram-bearing mudstones at Richardson on Lopez Island indicates a late Aptian (112-115 Ma), not late Albian (100 Ma) age as currently in the literature. The age brackets of thrusting, marked by these pre-thrusting mudstones and 84 Ma post-thrusting sedimentary rocks, span a much longer period than previously thought, diminishing controls on rates of displacement in the thrust system and timing of regional deformation in western Washington. New 40Ar/39Ar plateau ages of phengite in blueschist facies meta-volcanic rock, also at Richardson, are 124 ± 0.7 Ma (2_, late Barremian). These blueschist facies volcanic rocks are in fault contact with the fossiliferous mudstones. Therefore, at Richardson the blueschist facies metamorphism, previously inferred to be associated with the thrusting, now appears to have occurred prior to thrusting. Further, the Ar ages demonstrate that blueschist-facies fabric formed earlier than the thrust event and is therefore not directly useful in analyzing the thrusting kinematics. The Richardson 40Ar/39Ar age is similar to isotopic ages found in the eastern San Juan Islands and in the Shuksan blueschist terrane in the northwest Cascades, and thus fits into an emerging regional age-pattern of blueschist facies metamorphism during Late Jurassic - Early Cretaceous (up to Barremian) but not late Albian - Cenomanian. If this pattern is more broadly confirmed for the San Juan Islands, all the blueschist facies metamorphism can be regarded as having formed in subduction zones elsewhere along the continental margin rather than in the anomalous setting of an on-land thrust system as in the San Juan Islands
Symplectic Integration and Molecular Dynamics
No full textSymplectic integrators form an important class of numerical methods\ud
for molecular dynamics. We give a brief history of the development\ud
of symplectic geometry, followed by an overview of the field intended for\ud
readers with little or no background in this area. The presentation of symplectic geometry culminates with a proof of Liouville's Theorem, which is central to the success of symplectic integrators. We then present the popular Verlet algorithm and prove that it is symplectic. Comparing the\ud
Verlet algorithm with the non-symplectic Euler method, we demonstrate\ud
the qualitative advantages of symplectic methods for integrating Hamiltonian systems. Finally, we apply the Verlet algorithm to the Lennard-Jones potential, a simple nonlinear problem in molecular dynamics. In this simulation, we demonstrate numerical resonance, a phenomenon in which certain timesteps for integration interact with the natural frequency of a\ud
physical system, leading to extremely inaccurate results
The Simplex Algorithm of Linear Programming
No full textThis paper deals with the simplex method of linear programming, a division of\ud
operations research. Topics discussed include the simplex algorithm, the fundamental\ud
theorem of linear programming and the concept of duality. To facilitate understanding of\ud
these concepts, examples appear throughout the paper. In addition, applications of the\ud
simplex method in environmental engineering and land use programs will be studied
Fitzhugh-Nagumo Equations for the Action Potential of the Axon, Their Solutions and Stability
No full textIn this paper, a mathematical model for\ud
the action potential of an axon will be discussed. I will introduce some properties of the solutions to this model. The stability of these solutions is then\ud
considered in the analogy with a simpler case
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