A short note on the nested-sweep polarized traces method for the 2D Helmholtz equation

We present a variant of the solver in Zepeda-N\'u\~nez and Demanet (2014), for the 2D high-frequency Helmholtz equation in heterogeneous acoustic media. By changing the domain decomposition from a layered to a grid-like partition, this variant yields improved asymptotic online and offline runtimes and a lower memory footprint. The solver has online parallel complexity that scales \emph{sub linearly} as $\mathcal{O} \left( \frac{N}{P} \right)$, where $N$ is the number of volume unknowns, and $P$ is the number of processors, provided that $P = \mathcal{O}(N^{1/5})$. The variant in Zepeda-N\'u\~nez and Demanet (2014) only afforded $P = \mathcal{O}(N^{1/8})$. Algorithmic scalability is a prime requirement for wave simulation in regimes of interest for geophysical imaging.Comment: 5 pages, 5 figure

Charge and Magnetic Moment of the Neutrino in the Background Field Method and in the Linear R_xi^L Gauge

We present a computation of the charge and the magnetic moment of the neutrino in the recently developed electro-weak Background Field Method and in the linear $R_{\xi}^L$ gauge. First, we deduce a formal Ward-Takahashi identity which implies the immediate cancellation of the neutrino electric charge. This Ward-Takahashi identity is as simple as that for QED. The computation of the (proper and improper) one loop vertex diagrams contributing to the neutrino electric charge is also presented in an arbitrary gauge, checking in this way the Ward-Takahashi identity previously obtained. Finally, the calculation of the magnetic moment of the neutrino, in the minimal extension of the Standard Model with massive Dirac neutrinos, is presented, showing its gauge parameter and gauge structure independence explicitly.Comment: Latex, 19 pages, 9 PS and 10 EPS figures. One reference added. Appendix B modified and Appendices C-E eliminated. To be published in Eur. Phys. J.

Fourier Method for Approximating Eigenvalues of Indefinite Stekloff Operator

We introduce an efficient method for computing the Stekloff eigenvalues associated with the Helmholtz equation. In general, this eigenvalue problem requires solving the Helmholtz equation with Dirichlet and/or Neumann boundary condition repeatedly. We propose solving the related constant coefficient Helmholtz equation with Fast Fourier Transform (FFT) based on carefully designed extensions and restrictions of the equation. The proposed Fourier method, combined with proper eigensolver, results in an efficient and clear approach for computing the Stekloff eigenvalues.Comment: 12 pages, 4 figure

One Step Non SUSY Unification

We show that it is possible to achieve one step gauge coupling unification in a general class of non supersymmetric models which at low energies have only the standard particle content and extra Higgs fields doublets. The constraints are the experimental values of $\alpha_{em}$, $\alpha_s$ and $\sin^2\theta_W$ at $10^2 GeVs$, and the lower bounds for FCNC and proton decay rates. Specific example are pointed out.Comment: 10 pages, Latex file,, uses epsf style, Two Postscript figures included. To appear in Europhysics Letter

Sensory traits, color, and shelf life of low-dose irradiated, precooked, ground beef patties

Irradiation did not influence bitter, bloody, burnt, chemical, fat-like, juiciness, liver-like, beef identity, metallic, rancid, sour, sweet, and toughness flavor/textural attributes, beef aroma, or off-odor in precooked ground beef patties. Irradiation slightly increased the animal hair flavor note, but intensity levels were <1 on the 15-point sensory scale. Except for 10% fat non-irradiated controls, reheated precooked patties had a slight sour, ammonia-like, top note. Irradiation at 3.5 kilograys (kGy) increased external redness in vacuum-packaged patties, but not in aerobic packages. Aerobic packaging with or without irradiation decreased external precooked redness. Oxidative rancidity increased when patties were irradiated in aerobic but not in vacuum packages. Reduction of oxygen in vacuum bags extended the shelf life of the precooked ground beef patties, at least in terms of oxidative rancidity. Precooking ground beef patties, irrespective of irradiation or packaging type, posed sensory disadvantages, and improvements to the precooking process are needed before irradiating at low-dose levels is appropriate

Gold−Copper Nano-Alloy, “Tumbaga”, in the era of nano: phase diagram and segregation

Gold–copper (Au–Cu) phases were employed already by pre-Columbian civilizations, essentially in decorative arts, whereas nowadays, they emerge in nanotechnology as an important catalyst. The knowledge of the phase diagram is critical to understanding the performance of a material. However, experimental determination of nanophase diagrams is rare because calorimetry remains quite challenging at the nanoscale; theoretical investigations, therefore, are welcomed. Using nanothermodynamics, this paper presents the phase diagrams of various polyhedral nanoparticles (tetrahedron, cube, octahedron, decahedron, dodecahedron, rhombic dodecahedron, truncated octahedron, cuboctahedron, and icosahedron) at sizes 4 and 10 nm. One finds, for all the shapes investigated, that the congruent melting point of these nanoparticles is shifted with respect to both size and composition (copper enrichment). Segregation reveals a gold enrichment at the surface, leading to a kind of core–shell structure, reminiscent of the historical artifacts. Finally, the most stable structures were determined to be the dodecahedron, truncated octahedron, and icosahedron with a Cu-rich core/Au-rich surface. The results of the thermodynamic approach are compared and supported by molecular-dynamics simulations and by electron-microscopy (EDX) observations

Tendency in the growth of creole kids in extensive systems

The present investigation was developed at the State of Puebla, Mexico, to describe the tendency in the growth of Creole kids by means of the evaluation of the average daily weight gain (ADWG). A total of 161 kids were controlled from the birth to the 102 days of age. Every 15 days the kids were weighed, previous fasting with separation of the mother from afternoon of the previous day. The variables included were date and weight at birth, sex, childbirth type and weights every 15 days. The results show that the average weight to the birth was 2.562 ± 0.583 kg, the males surpassing females (p<0.01) in 9.57 percent (0.232 kg). Differences were observed in favour of those of simple childbirth. The final weight was 10.186 ± 2.723 kg for the females and 11.508 ± 3.616 kg for the males. The males from simple childbirth reached a greater weight (12.229 kg). The average daily weight gain (g) for all the animals was of 82.37 ± 26.9 g. The weight at the first month reached 106.2 g; at the second 95.5 g and 53.9 g at third. The smaller gains are observed in the females born from double childbirth with 64.01 ± 17.1 g, whereas the best growth behavior was find in males from simple childbirth with 94.34 ± 30.31 g. The better adjustment of the growth was obtained with potential type equations for the total of kids (Y= 3.23X0.262); second degree polynomial equations were better for the females (Y= 3.35 + 0.07497X -0.00007085 X2); potential equations for males (Y= 4.23X0.21); and also, potential for kids of simple childbirth (Y= 3.91X0.23) and second degree polynomial equations for kids of double childbirth (Y= 3.26 + 0.0947X - 0.00002069 X2).En el Estado de Puebla, México, se desarrolló la presente investigación con el objetivo de describir la tendencia en el crecimiento de cabritos criollos mediante la evaluación de la ganancia media diaria de peso (GMDp). Se dio seguimiento individual a 161 cabritos desde el nacimiento hasta los 102 días de edad, pesándose cada 15 días, previo ayuno con separación de la madre desde la tarde del día anterior. Las variables consideradas fueron fecha y peso de nacimiento, sexo, tipo de parto y pesos quincenales. Los resultados muestran que el peso promedio al nacimiento es de 2,562 ± 0,583 kg, superando los machos a las hembras (p<0,01) en un 9,57 p.100 (0,232 kg). Los de parto simple tuvieron mejor comportamiento. El peso final fue de 10,186 ± 2,723 kg para las hembras y de 11,508 ± 3,616 kg para los machos. La ganancia media diaria de peso (g) para el total de los animales fue de 82,37 ± 26,9 g en promedio. Por períodos, al primer mes alcanzan 106,2 g; en el segundo 95,5 g y 53,9 en el tercero. Las menores ganancias se observan en las hembras nacidas de parto gemelar, con 64,01 ± 17,1 g, mientras que el mejor comportamiento lo tienen los machos simples con 94,34 ± 30,31g. Las ecuaciones de mejor ajuste del crecimiento fueron de tipo potencial para el total de cabritos (Y= 3,23X 0,262); polinomial de segundo grado para las hembras (Y= 3,35 + 0,07497X - 0,00007085X2); potencial para machos (Y= 4,23X 0,21); potencial para cabritos de parto simple (Y =3,91X 0,23) y polinomial de segundo grado para cabritos de parto doble (Y= 3,26 + 0,0947X - 0,00002069X2)

Sensory traits, color, and shelf life of low-dose irradiated, raw, ground beef patties

Irradiation of raw ground beef patties had minimal effects on flavor and aroma of patties after cooking. Oxidative rancidity increased when patties were irradiated in aerobic but not in vacuum packages. Irradiation of vacuum-packaged ground beef patties produced a more stable color. In both packaging types, irradiation significantly reduced microbial growth during storage