Matrix Representation of Octonions and Generalizations

We define a special matrix multiplication among a special subset of 2N\x 2N matrices, and study the resulting (non-associative) algebras and their subalgebras. We derive the conditions under which these algebras become alternative non-associative and when they become associative. In particular, these algebras yield special matrix representations of octonions and complex numbers; they naturally lead to the Cayley-Dickson doubling process. Our matrix representation of octonions also yields elegant insights into Dirac's equation for a free particle. A few other results and remarks arise as byproducts.Comment: 18 printed page

Determination of bonding parameters and inspection techniques for cadmium-to-stainless steel bonds and assembly of two capsule housings Final report

Bonding parameters and quality control for cadmium-stainless steel clad fuel pellet containment vessel productio

Surrogate-assisted network analysis of nonlinear time series

The performance of recurrence networks and symbolic networks to detect weak nonlinearities in time series is compared to the nonlinear prediction error. For the synthetic data of the Lorenz system, the network measures show a comparable performance. In the case of relatively short and noisy real-world data from active galactic nuclei, the nonlinear prediction error yields more robust results than the network measures. The tests are based on surrogate data sets. The correlations in the Fourier phases of data sets from some surrogate generating algorithms are also examined. The phase correlations are shown to have an impact on the performance of the tests for nonlinearity.Comment: 9 pages, 5 figures, Chaos (http://scitation.aip.org/content/aip/journal/chaos), corrected typo

Design concepts for bioreactors in space

Microbial food sources are becoming viable and more efficient alternatives to conventional food sources especially in the context of Closed Ecological Life Support Systems (CELSS) in space habitats. Since bioreactor designs for terrestrial operation will not readily apply to conditions of microgravity, there is an urgent need to learn about the differences. These differences cannot be easily estimated due to the complex nature of the mass transport and mixing mechanisms in fermenters. Therefore, a systematic and expeditious experimental program must be undertaken to obtain the engineering data necessary to lay down the foundations of designing bioreactors for microgravity. Two bioreactor design concepts presented represent two dissimilar approaches to grappling with the absence of gravity in space habitats and deserve to be tested for adoption as important components of the life support function aboard spacecrafts, space stations and other extra-terrestrial habitats

A FRAMEWORK FOR EFFECTIVE INDUSTRY STRATEGIC PLANNING

As agricultural commodity industries strategically plan for their future, they need to consider the systemic and synergistic effects of such factors as changing government regulations, demand expansion or contraction, globalized markets, increased competitive pressures, and greater customer quality requirements. This article discusses a framework developed to help industries strategically plan within the context of these dynamic factors. This framework, based upon relevant theory and an accumulation of experiences with this type of strategic planning, provides one possible approach for addressing the strategic needs of an entire industry. In this way, a commodity industry as a whole can identify and address key industrywide strategic issues to maintain and enhance its competitiveness, profitability, or at the very least, its survival in increasingly global markets.framework, industry, strategic planning, Agribusiness,

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

The author has identified the following significant results. ERTS-1 multispectral scanner imagery of the nearshore surface waters of the Northeast Pacific Ocean is proving to be a useful tool for determining source and dispersal of suspended particulate matter. The principal sources of the turbid water, seen best on the green and red bands, are river and stream effluents and actively eroding coastlines; secondary sources are waste effluents and production of planktonic organisms, but these may sometimes be masked by the very turbid plumes of suspended sediment being discharged into the nearshore zone during times of high river discharge. The configuration and distribution of the plumes of turbid water also can be used to infer near-surface current directions. Comparison of imagery of the nearshore water off the northern California coast from October 1972 and January 1973 shows a reversal of the near-surface currents, from predominantly south-setting in the fall (California Current) to north-setting in the winter (Davidson Current)

Design concepts for bioreactors in space

Microbial food sources are becoming viable and more efficient alternatives to conventional food sources, especially in the context of closed ecological life support systems (CELSS) in space habitats. Two bioreactor design concepts presented represent two dissimilar approaches to grappling with the absence of gravity in space habitats and deserve to be tested for adoption as important components of the life support function aboard spacecraft, space stations and other extra-terrestrial habitats

Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris.

Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. We also obtained video footage from seal-mounted videos to understand their feeding in the OMZ. While the diel vertical migration pattern was apparent for most depths of the JME, some very deep dives, beyond the normal diel depth ranges, occurred episodically during daylight hours. The midmesopelagic zone was the main foraging zone for all seals. Larger seals tended to show smaller numbers of JME and lower feeding rates than smaller seals during migration, suggesting that larger seals tended to feed on larger prey to satisfy their metabolic needs. Larger seals also dived frequently to the deep OMZ, possibly because of a greater diving ability than smaller seals, suggesting their dependency on food in the deeper depth zones. Video observations showed that seals encountered the rarely reported ragfish (Icosteus aenigmaticus) in the depths of the OMZ, which failed to show an escape response from the seals, suggesting that low oxygen concentrations might reduce prey mobility. Less mobile prey in OMZ would enhance the efficiency of foraging in this zone, especially for large seals that can dive deeper and longer. We suggest that the OMZ plays an important role in structuring the mesopelagic ecosystem and for the survival and evolution of elephant seals

The influence of seagrass cover on population structure and individual growth rate of a suspension-feeding bivalve, Mercenaria mercenaria

The average density of Mercenaria mercenaria in 216 ¼-m2 samples taken in spring 1980 from an eelgrass (Zostera marina) bed in Back Sound, North Carolina, was 9.0 m–2, more than five times the average density (1.6 m–2) in 216 ¼-m2 samples from a nearby sand flat. Size-frequency distributions differed between environments, with the sand flat containing a larger fraction of its Mercenaria in the smallest size class (0–1 cm). Use of internal growth lines to age all Mercenaria collected revealed that age-frequency distributions also differed between environments but that average Mercenaria age was identical in the two collections. The average sizes of 0-, 1-, and 2-year-class Mercenaria were significantly greater in the seagrass collection. Furthermore, the logarithmic growth curve fit through the mean sizes of each year class for the seagrass collection fell significantly above the analogous sand-flat curve for all ages, implying higher growth rates inside the seagrass environment. The seagrass environment contained a higher proportion of finer sediments, more silts and clays, and higher organic content both in surface (0–2 cm) and-in deep (0–20 cm) cores. Current velocities measured by dye release in the field demonstrated a substantial baffling effect by the seagrass, with average surface velocities above the blades about 3–5 × average velocities at depths within the seagrass canopy. This baffling by seagrass reduced currents near the bottom, where Mercenaria feeds, to levels 50% lower than those measured simultaneously on the sand flat. The paradoxically higher growth rate of the filter-feeding Mercenaria in the lower current regime inside the seagrass bed may be a consequence of higher particulate food concentrations produced by the hydrodynamic baffling of the emergent vegetation

Brownian dynamics around the core of self-gravitating systems

We derive the non-Maxwellian distribution of self-gravitating $N$-body systems around the core by a model based on the random process with the additive and the multiplicative noise. The number density can be obtained through the steady state solution of the Fokker-Planck equation corresponding to the random process. We exhibit that the number density becomes equal to that of the King model around the core by adjusting the friction coefficient and the intensity of the multiplicative noise. We also show that our model can be applied in the system which has a heavier particle. Moreover, we confirm the validity of our model by comparing with our numerical simulation.Comment: 11 pages, 4 figure