Aceite de semilla de nopal prensado en frío: calidad y estabilidad

Cold-pressed seed oil from twelve commercially produced cactus pear cultivars was assessed for oil yield, fatty acid composition, physicochemical properties, quality and stability. Large differences in oil content, fatty acid composition and physicochemical properties (IV, PV, RI, tocopherols, ORAC, % FFA, OSI and induction time) were observed. Oil content ranged between 2.51% and 5.96% (Meyers and American Giant). The important fatty acids detected were C16:0, C18:0, C18:1c9 and C18:2c9,12, with C18:2c9,12, the dominating fatty acid, ranging from 58.56-65.73%, followed by C18:1c9, ranging between 13.18-16.07%, C16:0, which ranged between 10.97 - 15.07% and C18:0, which ranged between 2.62-3.18%. Other fatty acids such as C14:0, C16:1c9, C17:0, C17:1c10, C20:0, C18:3c9,12,15 and C20:3c8,11,14 were detected in small amounts. The quality parameters of the oils were strongly influenced by oil content, fatty acid composition and physicochemical properties. Oil content, PV, % FFA, RI, IV, tocopherols, ORAC and ρ-anisidine value were negatively correlated with OSI. C18:0; C18:1c9; C18:2c9,12; MUFA; PUFA; n-6 and PUFA/SFA were also negatively correlated with OSI. Among all the cultivars, American Giant was identified as the paramount cultivar with good quality traits (oil content and oxidative stability).Se evaluó el rendimiento de aceite, la composición en ácidos grasos, las propiedades fisicoquímicas, la calidad y la estabilidad del aceite de semilla prensadas en frío de doce cultivares de nopal producidos comercialmente. Se observaron grandes diferencias en el contenido de aceite, la composición en ácidos grasos y las propiedades fisicoquímicas (IV, PV, RI, tocoferoles, ORAC, % FFA, OSI y tiempo de inducción). El contenido de aceite varió entre 2,51-5,96% (Meyers y American Giant). Los ácidos grasos mayoritarios fueron C16:0, C18:0, C18:1c9 y C18:2c9,12, siendo el C18:2c9,12 el mayoritario con porcentajes entre 58,56-65,73, seguido de C18:c9 que varía entre 13,18-16,07%, C16:0, 10,97-15.07% y C18:0 entre 2,62-3,18%. Otros ácidos grasos, tales como C14:0, C16:1c9, C17:1c10, C20:0, C18:3c9,12,15 y C20:3c8,11,14 se detectaron en pequeñas cantidades. Los parámetros de calidad de los aceites estuvieron estrechamente influenciados por el contenido total de aceite, la composición de ácidos grasos y las propiedades fisicoquímicas. El contenido de aceite, PV, % FFA, RI, IV, tocoferoles, ORAC y el valor de ρ-anisidina se correlacionaron negativamente con OSI. C18:0; C18:1c9; C18: 2c9,12; MUFA; PUFA; n-6 y PUFA / SFA también se correlacionaron negativamente con OSI. Entre todos los cultivares, American Giant fue identificado como el cultivar primordial con rasgos de buena calidad (contenido de aceite y estabilidad oxidativa)

Dirac sheets and gauge fixing in U(1)U(1) lattice gauge theory

Photon correlators in $~U(1)~$ pure gauge theory for different lattice actions are considered under the Lorentz gauge condition. They are shown to depend strongly on the gauge fixing ambiguity and on the corresponding existence of Dirac sheets. For the Coulomb phase a gauge fixing algorithm is proposed which avoids Dirac sheets and allows to find the global extremum of the non-local gauge condition. Sorry, figures are not included and can be sent by ordinary mail.Comment: 11 pages preprint HU Berlin--IEP--93/2, June 199

Experiments of Interfacial Roughening in Hele-Shaw Flows with Weak Quenched Disorder

We have studied the kinetic roughening of an oil--air interface in a forced imbibition experiment in a horizontal Hele--Shaw cell with quenched disorder. Different disorder configurations, characterized by their persistence length in the direction of growth, have been explored by varying the average interface velocity v and the gap spacing b. Through the analysis of the rms width as a function of time, we have measured a growth exponent beta ~= 0.5 that is almost independent of the experimental parameters. The analysis of the roughness exponent alpha through the power spectrum have shown different behaviors at short (alpha_1) and long (alpha_2) length scales, separated by a crossover wavenumber q_c. The values of the measured roughness exponents depend on experimental parameters, but at large velocities we obtain alpha_1 ~= 1.3 independently of the disorder configuration. The dependence of the crossover wavenumber with the experimental parameters has also been investigated, measuring q_c ~ v^{0.47} for the shortest persistence length, in agreement with theoretical predictions.Comment: 20 pages, 22 figure

Consumer Behavior Analysis and Social Marketing: The Case of Environmental Conservation

Consumer behavior analysis represents one development within the behavior-analytic tradition of interpreting complex behavior, in which a specific conceptual framework has been proposed (i.e., the Behavioral Perspective Model). According to this model, consumer behavior occurs at the intersection of a consumer-behavior setting and an individual’s learning history of consumption and is a function of utilitarian (mediated by the product) and informational (mediated by other persons) consequences. The model has been useful in analyses of consumers’ brand choice and reactions to different settings. In the present paper, the model was applied to the interpretation of environmental deleterious behaviors (use of private transportation, consumption of domestic energy, waste disposal, and domestic consumption of water). This application pointed to specific marketing strategies that should be adopted to modify each of these operant classes

Hadron masses in qQCD with Wilson fermions near the chiral limit

In quenched lattice QCD with standard Wilson fermions the quark propagator is computed very close to the chiral limit in the zero-temperature case. Starting from our experience with lattice QED we employ a modified statistical method in order to estimate reliably hadron masses.Comment: 8 (single column-) pages, contribution to LATTICE 9

Higher Spin Symmetry and N=4 SYM

We assemble the spectrum of single-trace operators in free N=4 SU(N) SYM theory into irreducible representations of the Higher Spin symmetry algebra hs(2,2|4). Higher Spin representations or YT-pletons are associated to Young tableaux (YT) corresponding to representations of the symmetric group compatible with the cyclicity of color traces. After turning on interactions, YT-pletons decompose into infinite towers of representations of the superconformal algebra PSU(2,2|4) and anomalous dimensions are generated. We work out the decompositions of tripletons with respect to the N=4 superconformal algebra PSU(2,2|4) and compute their one anomalous dimensions at large N. We then focus on operators/states sitting in semishort superconformal multiplets. By passing them through a semishort-sieve that removes superdescendants, we derive compact expressions for the partition function of semishort primaries.Comment: 38 pages, no figures. v2: references adde

Experiments on the twisted vortex state in superfluid 3He-B

We have performed measurements and numerical simulations on a bundle of vortex lines which is expanding along a rotating column of initially vortex-free 3He-B. Expanding vortices form a propagating front: Within the front the superfluid is involved in rotation and behind the front the twisted vortex state forms, which eventually relaxes to the equilibrium vortex state. We have measured the magnitude of the twist and its relaxation rate as function of temperature above 0.3Tc. We also demonstrate that the integrity of the propagating vortex front results from axial superfluid flow, induced by the twist.Comment: prepared for proceedings of the QFS2007 symposium in Kaza

Inflationary Attractors in F(R)F(R) Gravity

In this letter we shall demonstrate that the viable $F(R)$ gravities can be classified mainly into two classes of inflationary attractors, either the $R^2$ attractors or the $\alpha$-attractors. To show this, we shall derive the most general relation between the tensor-to-scalar ratio $r$ and the spectral index of primordial curvature perturbations $n_s$, namely the $r-n_s$ relation, by assuming that the slow-roll condition constrains the values of the slow-roll indices. As we show, the relation between the tensor-to-scalar ratio and the spectral index of the primordial curvature perturbations has the form $r\simeq \frac{48 (1-n_s)^2}{(4-x)^2}$, where the dimensionless parameter $x$ contains higher derivatives of the $F(R)$ gravity function with respect to the Ricci scalar, and it is a function of the $e$-foldings number $N$ and may also be a function of the free parameters of the various $F(R)$ gravity models. For $F(R)$ gravities which have a spectral index compatible with the observational data and also yield $x\ll 1$, these belong to the $R^2$-type of attractors, with $r\sim 3 (1-n_s)^2$, and these are viable theories. Moreover, in the case that $x$ takes larger values in specific ranges and is constant for a given $F(R)$ gravity, the resulting $r-n_s$ relation has the form $r\sim 3 \alpha (1-n_s)^2$, where $\alpha$ is a constant. Thus we conclude that the viable $F(R)$ gravities may be classified into two limiting types of $r-n_s$ relations, one identical to the $R^2$ model at leading order in $x$, and one similar to the $\alpha$-attractors $r-n_s$ relation, for the $F(R)$ gravity models that yield $x$ constant. Finally, we also discuss the case that $x$ is not constant.Comment: PLB Accepte

Fatty Acid Methyl Esters as Biosolvents of Epoxy Resins: A Physicochemical Study

The C8 to C18 fatty acid methyl esters (FAME) have been compared as solvents for two epoxy resin pre-polymers, bisphenol A diglycidyl ether (DGEBA) and triglycidyl paminophenol ether (TGPA). It was found that the solubilization limits vary according to the ester and that methyl caprylate is the best solvent of both resins. To explain these solubility performances, physical and chemical properties of FAME were studied, such as the Hansen parameters, viscosity, binary diffusion coefficient and vaporization enthalpy. Determination of the physicochemical parameters of FAME was carried out by laboratory experimentations and by calculation from bibliographic data. The Hansen parameters of FAME and epoxy resins pre-polymers were theoretically and experimentally determined. The FAME chain length showed a long dependence on the binary diffusion parameters and kinematic viscosity, which are mass and momentum transport properties. Moreover, the vaporization enthalpy of these compounds was directly correlated with the solubilization limits