An efficient coding system for deep space probes with specific application to Pioneer missions

One-half rate convolutional encoding with sequential decoding for deep space probe telemetry links with application to Pioneer mission

Generalized Lifshitz-Kosevich scaling at quantum criticality from the holographic correspondence

We characterize quantum oscillations in the magnetic susceptibility of a quantum critical non-Fermi liquid. The computation is performed in a strongly interacting regime using the nonperturbative holographic correspondence. The temperature dependence of the amplitude of the oscillations is shown to depend on a critical exponent nu. For general nu the temperature scaling is distinct from the textbook Lifshitz-Kosevich formula. At the `marginal' value nu = 1/2, the Lifshitz-Kosevich formula is recovered despite strong interactions. As a by-product of our analysis we present a formalism for computing the amplitude of quantum oscillations for general fermionic theories very efficiently.Comment: 18 pages, pdftex, 1 figure. v2: figure and few comments adde

Contextual Studies of the Middle Archaic Component at Cave Spring in Middle Tennessee

Research in 1980 and 1981 at the Cave Spring site, located on the Duck River in the Nashville Basin of Middle Tennessee, revealed a buried paleosol in a Holocene terrace which contained charcoal, river gravel and chipped stone artifacts. Radiocarbon dates from this buried stratum range from 6500 to 7300 years before present. Evaluating the potential of this buried deposit for yielding behaviorally significant information depended upon learning (1) whether the cultural materials were undisturbed or were redeposited by the river, (2) whether one or several periods of deposition or occupation were represented, and (3) whether material from one or more than one cultural group was included in the deposit. Gravel from the excavation was studied and compared to control samples from a nearby gravel bar and from a Pleistocene terrace. A significantly higher percentage of reddened and broken gravel occurred with the artifacts than in the control situations. This information, in conjunction with a gravel concentration exposed during excavation, suggests that the gravel had been culturally introduced for use in stone boiling or as hearth stones. Refitting analysis was conducted using chipped stone artifacts and debris to determine if the highly leptokurtic vertical distribution of artifacts resulted from disturbance processes or sequent occupations. Reconstructed flake sequences and conjoined artifact fragments documented that vertical post depositional movement of these buried materials had occurred. Pieces from the same refitted set had dispersed as much as 40 cm vertically through silty clay during the past 7,000 years. Horizontal movement of pieces and systematic size sorting, as would result from stream action, had not occurred. The problem of how many cultural groups were responsible for the archaeological remains was confronted using the Cave Spring projectile point-knife sample. Given the perspective of systematic chipped stone reduction, the concept of multistage types is developed. The Eva biface reduction system is proposed with the Eva multistage type encompassing a variety of morphological and functional states which reflect expectable variation in the reduction or uselife sequences of particular artifacts within the overall system. The variability observed in the Cave Spring projectile point-knife sample, including specimens traditionally classified as Morrow Mountain points, can be attributed to a single biface reduction system and we need not infer the activities of two distinct cultural groups in accounting for the observed variability. The Morrow Mountain type in the southern Appalachian region apparently represents a biface reduction system distinct from that in the Middle Tennessee region commonly denoted as the Eva-Morrow Mountain cluster. This conclusion has significant ramifications for the assignment of assemblages to specific archaeological taxonomic units, and for making appropriate assemblage comparisons. It is not tenable to refer variability in the archaeological record directly to cultural variability. The situational nature of behaviors which operated to create the archaeological record must also be considered

Allosteric collaboration between elongation factor G and the ribosomal L1 stalk directs tRNA movements during translation

Determining the mechanism by which transfer RNAs (tRNAs) rapidly and precisely transit through the ribosomal A, P and E sites during translation remains a major goal in the study of protein synthesis. Here, we report the real-time dynamics of the L1 stalk, a structural element of the large ribosomal subunit that is implicated in directing tRNA movements during translation. Within pre-translocation ribosomal complexes, the L1 stalk exists in a dynamic equilibrium between open and closed conformations. Binding of elongation factor G (EF-G) shifts this equilibrium towards the closed conformation through one of at least two distinct kinetic mechanisms, where the identity of the P-site tRNA dictates the kinetic route that is taken. Within post-translocation complexes, L1 stalk dynamics are dependent on the presence and identity of the E-site tRNA. Collectively, our data demonstrate that EF-G and the L1 stalk allosterically collaborate to direct tRNA translocation from the P to the E sites, and suggest a model for the release of E-site tRNA

On the Singularities of the Magnon S-matrix

We investigate the analytic structure of the magnon S-matrix in the spin-chain description of planar ${\cal N}=4$ SUSY Yang-Mills/$AdS_{5}\times S^{5}$ strings. Semiclassical analysis suggests that the exact S-matrix must have a large family of poles near the real axis in momentum space. In this article we show that these are double poles corresponding to the exchange of pairs of BPS magnons. Their locations in the complex plane are uniquely fixed by the known dispersion relation for the BPS particles. The locations precisely agree with the recent conjecture for the $S$ matrix by Beisert, Hernandez, Lopez, Eden and Staudacher (hep-th/0609044 and hep-th/0610251). These poles do not signal the presence of new bound states. In fact, a certain non-BPS localized classical solution, which was thought to give rise to new bound states, can actually decay into a pair of BPS magnons.Comment: 40 pages, 14 figures; typos corrected, references adde

G80-505 Economics of Energy Used in Fallow Systems for Winter Wheat-Fallow Rotation

This NebGuide discusses the economic advantages of using a fallow system with winter wheat. In 1979, Americans watched gasoline, diesel, and other petroleum products dramatically increase in price. The amount of imported crude oil increased and the demand continued strong despite higher prices. Conservation of energy, either forced or voluntary, seems to be one of the key solutions to the energy crisis

On Central Charges and Hamiltonians for 0-brane dynamics

We consider general properties of central charges of zero branes and associated duality invariants, in view of their double role, on the bulk and on the world volume (quantum-mechanical) theory. A detailed study of the BPS condition for the mass spectrum arising from toroidal compactifications is given for 1/2, 1/4 and 1/8 BPS states in any dimensions. As a byproduct, we retreive the U-duality invariant conditions on the charge (zero mode) spectrum and the orbit classification of BPS states preserving different fractions of supersymmetry. The BPS condition for 0-branes in theories with 16 supersymmetries in any dimension is also discussed.Comment: 23 pages, latex fil