Drawn to the Sea: Charles Bradford Hudson (1865-1939), Artist, Author, Army Officer, with Special Notice of His Work for the United States Fish Commission and Bureau of Fisheries

The biography of Charles Bradford Hudson that follows this preface had its seeds about 1965 when I (VGS) was casually examining the extensive files of original illustrations of fishes stored in the Division of Fishes, National Museum of Natural History, Smithsonian Institution. I happened upon the unpublished illustration of a rainbow trout by Hudson and was greatly impressed with its quality. The thought occurred to me then that the artist must have gone on to do more than just illustrate fishes. During the next 20 years I occasionally pawed through those files, which contained the work of numerous artists, who had worked from 1838 to the present. In 1985, I happened to discuss the files with my supervisor, who urged me to produce a museum exhibit of original fish illustrations. This I did, selecting 200 of the illustrations representing 21 artists, including, of course, Hudson. As part of the text for the exhibit, Drawn from the Sea, Art in the Service of Ichthyology, I prepared short biographies of each of the artists. The exhibit, with an available poster, was shown in the Museum for six months, and a reduced version was exhibited in U.S. and Canadian museums during the next 3 years

A unique facility for V/STOL aircraft hover testing

The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight

Isometric Representations of Totally Ordered Semigroups

Let S be a subsemigroup of an abelian torsion-free group G. If S is a positive cone of G, then all C*-algebras generated by faithful isometrical non-unitary representations of S are canonically isomorphic. Proved by Murphy, this statement generalized the well-known theorems of Coburn and Douglas. In this note we prove the reverse. If all C*-algebras generated by faithful isometrical non-unitary representations of S are canonically isomorphic, then S is a positive cone of G. Also we consider G = Z\times Z and prove that if S induces total order on G, then there exist at least two unitarily not equivalent irreducible isometrical representation of S. And if the order is lexicographical-product order, then all such representations are unitarily equivalent.Comment: February 21, 2012. Kazan, Russi

Carter-Payne homomorphisms and Jantzen filtrations

We prove a q-analogue of the Carter-Payne theorem in the case where the differences between the parts of the partitions are sufficiently large. We identify a layer of the Jantzen filtration which contains the image of these Carter-Payne homomorphisms and we show how these homomorphisms compose.Comment: 30 page

Particle-in-cell simulation of a mildly relativistic collision of an electron-ion plasma carrying a quasi-parallel magnetic field: Electron acceleration and magnetic field amplification at supernova shocks

Plasma processes close to SNR shocks result in the amplification of magnetic fields and in the acceleration of electrons, injecting them into the diffusive acceleration mechanism. The acceleration of electrons and the B field amplification by the collision of two plasma clouds, each consisting of electrons and ions, at a speed of 0.5c is investigated. A quasi-parallel guiding magnetic field, a cloud density ratio of 10 and a plasma temperature of 25 keV are considered. A quasi-planar shock forms at the front of the dense plasma cloud. It is mediated by a circularly left-hand polarized electromagnetic wave with an electric field component along the guiding magnetic field. Its propagation direction is close to that of the guiding field and orthogonal to the collision boundary. It has a low frequency and a wavelength that equals several times the ion inertial length, which would be indicative of a dispersive Alfven wave close to the ion cyclotron resonance frequency of the left-handed mode (ion whistler), provided that the frequency is appropriate. However, it moves with the super-alfvenic plasma collision speed, suggesting that it is an Alfven precursor or a nonlinear MHD wave such as a Short Large-Amplitude Magnetic Structure (SLAMS). The growth of the magnetic amplitude of this wave to values well in excess of those of the quasi-parallel guiding field and of the filamentation modes results in a quasi-perpendicular shock. We present evidence for the instability of this mode to a four wave interaction. The waves developing upstream of the dense cloud give rise to electron acceleration ahead of the collision boundary. Energy equipartition between the ions and the electrons is established at the shock and the electrons are accelerated to relativistic speeds.Comment: 16 pages, 18 figures, Accepted for publication by Astron & Astrophy

Proof of Stanley's conjecture about irreducible character values of the symmetric group

R. Stanley has found a nice combinatorial formula for characters of irreducible representations of the symmetric group of rectangular shape. Then, he has given a conjectural generalisation for any shape. Here, we will prove this formula using shifted Schur functions and Jucys-Murphy elements.Comment: 9 page

English Learning and Learning Disabilities: Has Research Made Its Way into Practice?

Fundamental to the hypothesis-driven approach to assessing the special-education (SPED) needs of English learners (ELs) is the awareness that behaviors often exhibited by ELs may mirror indicators of learning disabilities (e.g., difficulty comprehending text, difficulty following directions, lack of appropriate classroom behavior, lack of attention). We surveyed 330 school professionals to examine their perceptions about four mirrored behaviors displayed by ELs during instruction, as indicators of either a second-language difficulty or a learning disability. Only 31% of the respondents correctly indicated that none of the behaviors can distinguish these two possibilities. The probability of correct assessment was positively associated with the level of English-as-a-Second Language (ESL) training for those with less than 15 years of teaching experience and negatively associated for those with more than 20 years of experience. Correct assessment was positively associated with years of teaching experience for those with no ESL training but negatively associated for those with any level of ESL training. Correct assessment was not generally associated with the level of SPED training. From these results, we derive recommendations for improving the training of all pre- and in-service teachers in ESL instruction to better equip them to discriminate ELs’ language difficulties from learning disabilities

Do pedometers motivate people to walk more?

Physical activity confers many important health benefits. The 'active living message' recommends that adults should accumulate 30 ruin of moderate-intensity physical activity (e.g. brisk walking) on most--preferably all--days of the week, but the populations of most developed countries are not meeting this target. Walking is one mode of activity that most people can do without skills, equipment, facilities or extra expense and walking has less bias in terms of age, sex and social class than facility-based exercise. Thus we need to investigate interventions that promote walking