Clifford algebra with mathematica

The Clifford algebra of a n-dimensional Euclidean vector space provides a general language comprising vectors, complex numbers, quaternions, Grassman algebra, Pauli and Dirac matrices. In this work, we present an introduction to the main ideas of Clifford algebra, with the main goal to develop a package for Clifford algebra calculations for the computer algebra program Mathematica. The Clifford algebra package is thus a powerful tool since it allows the manipulation of all Clifford mathematical objects. The package also provides a visualization tool for elements of Clifford Algebra in the 3-dimensional space

Towards binocular active vision in a robot head system

This paper presents the first results of an investigation and pilot study into an active, binocular vision system that combines binocular vergence, object recognition and attention control in a unified framework. The prototype developed is capable of identifying, targeting, verging on and recognizing objects in a highly-cluttered scene without the need for calibration or other knowledge of the camera geometry. This is achieved by implementing all image analysis in a symbolic space without creating explicit pixel-space maps. The system structure is based on the ‘searchlight metaphor’ of biological systems. We present results of a first pilot investigation that yield a maximum vergence error of 6.4 pixels, while seven of nine known objects were recognized in a high-cluttered environment. Finally a “stepping stone” visual search strategy was demonstrated, taking a total of 40 saccades to find two known objects in the workspace, neither of which appeared simultaneously within the Field of View resulting from any individual saccade

Maximum power, ecological function and efficiency of an irreversible Carnot cycle. A cost and effectiveness optimization

In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.Comment: 17 pages, 4 figures. Submitted to Energy Convers. Manag

Clustering of red Galaxies near the Radio-loud Quasar 1335.8+2834 at z=1.1

We have obtained new deep optical and near-infrared images of the field of the radio-loud quasar 1335.8+2834 at $z=1.086$ where an excess in the surface number density of galaxies was reported by Hutchings et al. [AJ, 106, 1324] from optical data. We found a significant clustering of objects with very red optical-near infrared colors, $4 \lesssim R-K \lesssim 6$ and $3 \lesssim I-K \lesssim 5$ near the quasar. The colors and magnitudes of the reddest objects are consistent with those of old (12 Gyr old at z=0) passively-evolving elliptical galaxies seen at $z=1.1$, clearly defining a `red envelope' like that found in galaxy clusters at similar or lower redshifts. This evidence strongly suggests that the quasar resides in a moderately-rich cluster of galaxies (richness-class $\geq 0$). There is also a relatively large fraction of objects with moderately red colors ($3.5 < R-K < 4.5$) which have a distribution on the sky similar to that of the reddest objects. They may be interpreted as cluster galaxies with some recent or on-going star formation.Comment: 14 pages text, 5 PostScript figures, 1 GIF figure, and 1 combined PS file. Accepted for ApJ, Letter

Implications of genotype and amino acid sup-ply on pork quality

An experiment was conducted to evaluate the effect of different feeding regimes and genotypes on growth performance, carcass characteristics, composition and eating quality of pork under organic framework conditions. 198 individually housed pigs of 4 genotypes were allocated to three dietary treatments. Feeding regimes differed in relation to the supply of limiting amino acids (AA). The genotypes used were Pi x (DL x DE); Du x DL, Pi x German Swabian Hall (Pi x SH) and pure SH breed. While Pi x (DL x DE) pigs showed the highest carcass yields, pigs of the genotype Du x DL achieved higher values in dlwg and in meat composition compared to the other genotypes. Performance traits were significantly influenced by the feeding regime. Lean meat percentage and area of M.l.d. were significantly lower when a diet reduced in limited amino acids compared to the control treat-ment was fed. Backfat thickness was not influenced by the feeding regime. However, intramuscular fat content clearly increased when a diet without AA supplementation was fed. The results indicate that the limited availability of high quality feedstuffs in organic farming does not impair but improve the preconditions to produce pork of high eating quality

Effect of stocking density on growth and yield of GIFT tilapia under rice-fish production system

The study was conducted at the Central Experimental Station, Philippine Rice Research Institute, Maligaya, Science City of Munoz, Nueva Ecija, Philippines during the wet season to determine the suitable stocking density(s) for better growth and yield of fish under rice-fish production systems. Recovery rate of GIFT tilapia in different stocking densities ranged from 75.74 to 83.47%. Among different treatments, rice +5,000 fingerlings/ha and rice +10,000 fingerlings/ha resulted in the highest recovery rate of 83.33% and 83.47%, respectively. The lowest recovery rate of 75.75% was obtained from rice +20,000 fingerlings/ha, but similar to that was obtained (78.56%) from rice +15,000 fingerlings/ha. Significantly higher rate of gain in body weight and that of specific growth rate were recorded in the treatment from rice +5,000 fingerlings/ha, while other treatments resulted in similar absolute and specific growth rate. Fish yield increased significantly with relatively higher stocking densities, but higher densities produced maximum number of smaller fishes and also lower recovery rate

Patterns of Epiphytic Lichen Abundance on Aspen Stands in Proximity to Roads of Varying Vehicular Traffic

Although present in nearly any wild space with available moisture and on a wide variety of substrates, lichen, and its importance as a bioindicator for an ecosystem, is often overlooked. As air pollution becomes a greater concern for flora, fauna, and even humans, the story told by lichen growth becomes more useful as we try to make sense of the downstream effects of anthropogenic contributions to poor air quality. One such human-driven pollutant is the level of emissions that result from vehicular travel. The Jackson Hole area has experienced a large increase in vehicular traffic in the past five to ten years in relation to the tourist industry, yet the long term effects on the sought after wild places of the region have not been thoroughly explored. By looking at lichen abundance on aspen trees near roads, the effects of varying levels of vehicular traffic can be documented. Our research supports the relationship between increased vehicular traffic and decreased overall lichen abundance, as well as suggests further use of lichens as bioindicators for understanding the negative impacts of air pollutants and the health of an ecosystem as a whole