Entanglement scaling at first order phase transitions

First order quantum phase transitions (1QPTs) are signaled, in the thermodynamic limit, by discontinuous changes in the ground state properties. These discontinuities affect expectation values of observables, including spatial correlations. When a 1QPT is crossed in the vicinity of a second order one (2QPT), due to the correlation length divergence of the latter, the corresponding ground state is modified and it becomes increasingly difficult to determine the order of the transition when the size of the system is finite. Here we show that, in such situations, it is possible to apply finite size scaling to entanglement measures, as it has recently been done for the order parameters and the energy gap, in order to recover the correct thermodynamic limit. Such a finite size scaling can unambigously discriminate between first and second order phase transitions in the vicinity of multricritical points even when the singularities displayed by entanglement measures lead to controversial results

Order statistics for d-dimensional diffusion processes

We present results for the ordered sequence of first passage times of arrival of N random walkers at a boundary in Euclidean spaces of d dimensions

Clasificación de pimentones por índices de calidad espectrofotométricos. (Técnicas espectrofotométricas para la determinación de la calidad del pimentón).

Existe la necesidad de disponer de sistemas objetivos y rápidos para la determinación de la calidad de los productos agrícolas. Los sistemas ópticos y espectrofotométricos se han presentado como muy válidos para estos fines en muchos productos (Mohsenin, 1984) (tomates, peras, manzanas, patatas, carnes, huevos...) esto justifica el uso de estos métodos sobre nuevos materiales. Las restricciones impuestas a los colorantes artificiales por las nuevas legislaciones favorecen el consumo de colorantes de origen natural, como el pimentón. Es necesario encontrar un sistema rápido y eficaz que determine la calidad de este producto de creciente interés, (Mínguez, 1992; Conrad, 1987; Nagle 1979; Navarro y Costa, 1993 ). Además existen graves problemas en la comercialización de este producto por la poca transparencia del mercado. Se han producido, en los últimos años, importaciones de pimentón de Marruecos de muy baja calidad y precio, que se mezclaban con pequeñas proporciones de pimentón de humo, comercializándose como pimentón de alta calidad y a precios similares al pimentón producido en la Vera por el sistema tradicional, lo que supone un fraude. Es por tanto necesario encontrar un sistema que discrimine producto de alta calidad ( con color atractivo, alto nivel de carotenoides y alta estabilidad ) de pimentones de baja calidad o dañados ( por exceso de calor durante el secado, enranciamiento, etc.). El objetivo de este trabajo ha sido segregar diversas calidades de pimentón, para esto se disponía de pimentones procedentes de Extremadura, de líneas seleccionadas obtenidas por el SIA, secados por el método tradicional (humo) y con estufa, incluyendo muestras que presentan daños por quemado. Sin ningún conocimiento previo se ha trabajado sobre espectros de reflexión en VIS y NIR a los que se han aplicado ciertas transformaciones para la obtención de variables que fueran capaces de discriminar pimentones secados con humo de los secados con estufa y de los quemados. Realizando reiterados estudios estadísticos se ha llegado a establecer algunas variables útiles en la separación de estas tres clases, para ambos rangos del espectro

In vitro acidification potential and fermentation pattern of cereal grains incubated with inoculum from animals given forage or concentrate based diets

This work aimed to study the acidification and fermentation pattern of maize (M1, M2, M3), barley (B1, B2, B3) and sorghum (S1, S2, S3) varieties depending on the rumen environment (inoculum from forage or concentrate diets, FI or CI), in 10 h incubation series with a low buffered medium. With CI, gas volume from barley was similar to maize (P > 0.05) except at 4 and 6 h, when M2 and M1 were lower. Barley or maize varieties did not differ in gas production (P > 0.05). After 10 h, barley and maize produced on average 82.5 and 73.0 mL/g organic matter (OM), whereas S1, S2 and S3 rendered 68.4, 31.1 and 39.7 mL/g. With FI, differences between barley and maize were detected after 6 h (61.0, 35.3 and 14.1 mL/g OM at 10 h for barley, maize and sorghum). Among inocula, pH with CI was lower than with FI (P < 0.001). Incubation pH at 10 h was 5.51, 5.21 and 5.00 with CI, and 5.52, 5.85 and 5.91 with FI, for sorghum, maize and barley varieties. Gas production and total volatile fatty acid (VFA) concentration were higher (P < 0.001) with CI than FI (67.3 vs 36.8 mL/g and 31.0 vs 19.9 mmol/L at 10 and 8 h). Butyrate and valerate proportions were higher with CI (P < 0.001), whereas acetate and branched chain VFA were lower (P < 0.001). Fermentative activity against vitreous starch such as maize or sorghum was lower for forage than concentrate inoculum. Study of fermentation of starch-rich substrates in a low buffered medium gives a more realistic picture than conventionally buffered conditions

Systematic Analysis of Intracellular Trafficking Motifs Located within the Cytoplasmic Domain of Simian Immunodeficiency Virus Glycoprotein gp41

Previous studies have shown that truncation of the cytoplasmic-domain sequences of the simian immunodeficiency virus (SIV) envelope glycoprotein (Env) just prior to a potential intracellular-trafficking signal of the sequence YIHF can strongly increase Env protein expression on the cell surface, Env incorporation into virions and, at least in some contexts, virion infectivity. Here, all 12 potential intracellular-trafficking motifs (YXXΦ or LL/LI/IL) in the gp41 cytoplasmic domain (gp41CD) of SIVmac239 were analyzed by systematic mutagenesis. One single and 7 sequential combination mutants in this cytoplasmic domain were characterized. Cell-surface levels of Env were not significantly affected by any of the mutations. Most combination mutations resulted in moderate 3- to 8-fold increases in Env incorporation into virions. However, mutation of all 12 potential sites actually decreased Env incorporation into virions. Variant forms with 11 or 12 mutated sites exhibited 3-fold lower levels of inherent infectivity, while none of the other single or combination mutations that were studied significantly affected the inherent infectivity of SIVmac239. These minor effects of mutations in trafficking motifs form a stark contrast to the strong increases in cell-surface expression and Env incorporation which have previously been reported for large truncations of gp41CD. Surprisingly, mutation of potential trafficking motifs in gp41CD of SIVmac316, which differs by only one residue from gp41CD of SIVmac239, effectively recapitulated the increases in Env incorporation into virions observed with gp41CD truncations. Our results indicate that increases in Env surface expression and virion incorporation associated with truncation of SIVmac239 gp41CD are not fully explained by loss of consensus trafficking motifs