Conservation Laws in Cellular Automata

If X is a discrete abelian group and B a finite set, then a cellular automaton (CA) is a continuous map F:B^X-->B^X that commutes with all X-shifts. If g is a real-valued function on B, then, for any b in B^X, we define G(b) to be the sum over all x in X of g(b_x) (if finite). We say g is `conserved' by F if G is constant under the action of F. We characterize such `conservation laws' in several ways, deriving both theoretical consequences and practical tests, and provide a method for constructing all one-dimensional CA exhibiting a given conservation law.Comment: 19 pages, LaTeX 2E with one (1) Encapsulated PostScript figure. To appear in Nonlinearity. (v2) minor changes/corrections; new references added to bibliograph

Variasi Musiman Produksi Serasah Jenis-jenis Dominan Hutan Pegunungan Rendah Di Taman Nasional Gunung Halimun*[seasonal Variation of Dominant Tree Species Litterfall in Low Montane Forest Gunung Halimun National Park]

The litterfall of Allingia excelsa Noroflha, Schima wallichii (DC) Korth., Castanopsis acuminatissima (Bl.) A. DC, C. javanica (Bl.) A. DC. and Quercus lineata Blume, the dominant tree species of Lower Mountain at Gunung Halimun National Park - West Java were studied.The annual litterfall was 7.0 - 8.2 t ha y and the total litterfall was higher during the rainy season than in the dry season. Each dominant tree species had its own specific pattern of leaf shedding. A. excelsa shed their leaves at the end of the rainy season of the first year, during the biannual period of study, while Q. lineata was opposite.C.javanica shed their leaves mainly in the middle of the rainy season in January to February. There was no clear pattern of leaf shedding on C. acuminatissima,and the species was named as non-seasonally type, while S. wallichii, shed their leaves during the dry season, and was named as the dry season type

A Multiscale Approach to Determination of Thermal Properties and Changes in Free Energy: Application to Reconstruction of Dislocations in Silicon

We introduce an approach to exploit the existence of multiple levels of description of a physical system to radically accelerate the determination of thermodynamic quantities. We first give a proof of principle of the method using two empirical interatomic potential functions. We then apply the technique to feed information from an interatomic potential into otherwise inaccessible quantum mechanical tight-binding calculations of the reconstruction of partial dislocations in silicon at finite temperature. With this approach, comprehensive ab initio studies at finite temperature will now be possible.Comment: 5 pages, 3 figure

Total energy differences between SiC polytypes revisited

The total energy differences between various SiC polytypes (3C, 6H, 4H, 2H, 15R and 9R) were calculated using the full-potential linear muffin-tin orbital method using the Perdew-Wang-(91) generalized gradient approximation to the exchange-correlation functional in the density functional method. Numerical convergence versus k-point sampling and basis set completeness are demonstrated to be better than 1 meV/atom. The parameters of several generalized anisotropic next-nearest-neighbor Ising models are extracted and their significance and consequences for epitaxial growth are discussed.Comment: 8 pages, 3 figures, Latex, uses epsfig and revte

Sleep education in pediatric residency programs: A cross-cultural look

10.1186/1756-0500-6-130BMC Research Notes61

Neutrino emission via the plasma process in a magnetized plasma

Neutrino emission via the plasma process using the vertex formalism for QED in a strongly magnetized plasma is considered. A new vertex function is introduced to include the axial vector part of the weak interaction. Our results are compared with previous calculations, and the effect of the axial vector coupling on neutrino emission is discussed. The contribution from the axial vector coupling can be of the same order as or greater than the vector vector coupling under certain plasma conditions.Comment: 20 pages, 3 figure

Temporal dominance of sensations of peanuts and peanut products in relation to Hutchings and Lillford’s “breakdown path"

Hutchings and Lillford’s (Journal of Texture Studies, 19, 103-115, 1988) proposed a “breakdown path” whereby particle size reduction occurs through mastication in conjunction with the secretion of saliva to form a swallowable bolus. The swallowing trajectory of whole peanuts, peanut meal and peanut paste were studied with the temporal dominance of sensations technique. The sensations for whole peanuts progressed from hard, to crunchy, to chewy, to soft and ended compacted on teeth. Predictably peanut meal missed out the first two sensations, progressing from chewy, to soft and ending compacted on teeth. However peanut paste, which starts as a soft suspension with relatively little structure appears to thicken and stick to the palate during oral processing. We propose that the “hard to swallow” sensation elicited by peanut paste may be due to water absorption from the saliva as they mix in the mouth

Strong UA(1)U_A(1) breaking in radiative η\eta decays

We study the \egg, \egm and \epg decays using an extended three-flavor Nambu-Jona-Lasinio model that includes the 't~Hooft instanton induced interaction. We find that the $\eta$-meson mass, the \egg, \egm and \epg decay widths are in good agreement with the experimental values when the $U_{A}(1)$ breaking is strong and the flavor $SU(3)$ singlet-octet mixing angle $\theta$ is about zero. The calculated $\eta \gamma \gamma^\ast$ transition form factor has somewhat weaker dependence on the squared four-momentum of the virtual photon. The effects of the $U_A(1)$ anomaly on the scalar quark contents in the nucleon, the $\Sigma_{\pi N}$ and $\Sigma_{KN}$ terms and the baryon number one and two systems are also studied.Comment: 41 pages, LaTeX, 17 eps figures, uses epsf.sty and cite.st

Understanding the proton's spin structure

We discuss the tremendous progress that has been towards an understanding of how the spin of the proton is distributed on its quark and gluon constituents. This is a problem that began in earnest twenty years ago with the discovery of the proton ``spin crisis'' by the European Muon Collaboration. The discoveries prompted by that original work have given us unprecedented insight into the amount of spin carried by polarized gluons and the orbital angular momentum of the quarks.Comment: Review article for J. Phys. G, 1 figure, 22 page