Natural entropy fluctuations discriminate similar looking electric signals emitted from systems of different dynamics

Complexity measures are introduced, that quantify the change of the natural entropy fluctuations at different length scales in time-series emitted from systems operating far from equilibrium. They identify impending sudden cardiac death (SD) by analyzing fifteen minutes electrocardiograms, and comparing to those of truly healthy humans (H). These measures seem to be complementary to the ones suggested recently [Phys. Rev. E {\bf 70}, 011106 (2004)] and altogether enable the classification of individuals into three categories: H, heart disease patients and SD. All the SD individuals, who exhibit critical dynamics, result in a common behavior.Comment: Published in Physical Review

Entropy in the natural time-domain

A surrogate data analysis is presented, which is based on the fluctuations of the ``entropy'' $S$ defined in the natural time-domain [Phys. Rev. E {\bf 68}, 031106, 2003]. This entropy is not a static one as, for example, the Shannon entropy. The analysis is applied to three types of time-series, i.e., seismic electric signals, ``artificial'' noises and electrocardiograms, and ``recognizes'' the non-Markovianity in all these signals. Furthermore, it differentiates the electrocardiograms of healthy humans from those of the sudden cardiac death ones. If $\delta S$ and $\delta S_{shuf}$ denote the standard deviation when calculating the entropy by means of a time-window sweeping through the original data and the ``shuffled'' (randomized) data, respectively, it seems that the ratio $\delta S_{shuf}/\delta S$ plays a key-role. The physical meaning of $\delta S_{shuf}$ is investigated.Comment: Published in Physical Review

Modifiable Psychological Factors Affecting Functioning in Fibromyalgia.

OBJECTIVE: To examine the role of several interrelated, potentially modifiable psychological factors (i.e., mindfulness and catastrophizing) in influencing patient-reported functioning. METHODS: In this cross-sectional study, 107 patients with fibromyalgia completed self-report assessments of pain severity, functioning and impact of symptoms, mindfulness, and pain catastrophizing. Linear regression and bootstrapping mediation analyses were performed to assess the relationships between these factors. RESULTS: Pain intensity was significantly and positively associated with pain catastrophizing and impact of fibromyalgia on functioning. Linear regression analyses indicated that pain intensity, catastrophizing, and mindfulness affect functioning in fibromyalgia. Follow-up mediation analysis revealed a significant indirect effect of pain catastrophizing on the relationship between pain intensity and fibromyalgia functioning. CONCLUSION: Individuals with fibromyalgia who have higher levels of pain and catastrophizing, and lower levels of mindfulness, are more likely to experience impaired functioning. Our findings suggest that pain catastrophizing appears to be an especially important variable contributing to reduced functioning in women with fibromyalgia. Therefore, catastrophizing-reducing treatments (e.g., cognitive behavioral therapy) are likely to have direct, beneficial impacts on functioning

Illusory vowels in Spanish-English sequential bilinguals: Evidence that accurate L2 perception is neither necessary nor sufficient for accurate L2 production

Spanish native speakers are known to pronounce onset /sC/ clusters in English with a prothetic vowel, as in esport for sport, due to their native language phonotactic constraints. We assessed whether accurate production of e.g. spi instead of espi was related to accurate perceptual discrimination of this contrast in second language (L2) speech of Spanish–English sequential bilinguals. A same–different discrimination task in stimulus pairs such as spi–espi assessed speech perception and a phonemic verbal fluency task elicited speech production. Logistic mixed model regressions revealed significant differences in accuracy between the bilinguals and the English monolinguals, although some bilinguals performed within the monolingual range. For the production task, but not for the perception task, bilinguals with more exposure to English and greater grammatical knowledge of English performed significantly more accurately than those with less exposure and lower grammatical knowledge. There was no significant correlation between production accuracy and perception accuracy. Through examining phonotactic constraints, these results expand a growing body of research into single sounds which suggests dissociations between L2 perception and production. In contrast to predictions made by L2 speech models, the findings indicate that accurate L2 perception is neither necessary nor sufficient for accurate L2 production, and instead are interpreted to indicate that the two capacities recruit different executive control mechanisms and are acquired – at least to a certain extent – independently in L2 acquisition.Peer Reviewe

Lowering the operating temperature of gold acetylene hydrochlorination catalysts using oxidized carbon supports

The commercialization of gold for acetylene hydrochlorination represents a major scientific landmark. The development of second-generation gold catalysts continues with a focus on derivatives and drop-in replacements with higher activity and stability. Here, we show the influence that the support surface oxygen has on the activity of carbon supported gold catalysts. Variation in the surface oxygen content of carbon is achieved through careful modification of the Hummers chemical oxidation method prior to the deposition of gold. All oxidized carbon-based catalysts resulted in a marked increase in activity at 200 °C when compared to the standard nontreated carbon, with an optimum oxygen content of ca. 18 at % being observed. Increasing oxygen and relative concentration of C–O functionality yields catalysts with light-off temperatures 30–50 °C below the standard catalyst. This understanding opens a promising avenue to produce high activity acetylene hydrochlorination catalysts that can operate at lower temperatures

Sulfur promotion in Au/C catalyzed acetylene hydrochlorination

The formation of highly active and stable acetylene hydrochlorination catalysts is of great industrial importance. The successful replacement of the highly toxic mercuric chloride catalyst with gold has led to a flurry of research in this area. One key aspect, which led to the commercialization of the gold catalyst is the use of thiosulphate as a stabilizing ligand. This study investigates the use of a range of sulfur containing compounds as promoters for production of highly active Au/C catalysts. Promotion is observed across a range of metal sulfates, non‐metal sulfates, and sulfuric acid treatments. This observed enhancement can be optimized by careful consideration of either pre‐ or post‐treatments, concentration of dopants used, and modification of washing steps. Pre‐treatment of the carbon support with sulfuric acid (0.76 m) resulted in the most active Au/C in this series with an acetylene conversion of ≈70% at 200 °C

Thermorheological and textural behaviour of gluten-free gels obtained from chestnut and rice flours

Nowadays, as celiac disease is becoming more common the consumers’ demand for gluten-free products with high nutritional and taste quality is increasing. This work deals with the study of the impact of four novelty gluten-free sources: chestnut flour (Cf), whole rice flour (Rw), Carolino rice flour (Rc) and Agulha rice flour (Ra). Textural, thermorheological and stability performance of gluten-free gels using different experimental techniques were evaluated. Mixed gels were also produced for comparison. Texture parameters were determined from the texture profile analysis using a texturometer. Thermorheological oscillatory measurements were conducted in a stresscontrolled rheometer in order to clarify the kinetics of gel formation and to characterise the structure of the matured gels. The stability of the gels was evaluated using transmittance profiling of the gels under gravitational fields (LUMiSizer®). Texture studies suggested that gels from mixtures of chestnut flour at 30 % and rice flour at 20 % showed the right texture to develop gel-based new desserts. Rheological results showed that the thermal profiles on heating of Cf gels were similar to those obtained for Rw and Ra, whereas Rc gels exhibited a particular pattern. Once the final gelatinisation temperature was achieved, no significant differences on the viscoelastic properties were noticed for all the tested gels. Stability tests showed that gels with Rc should present an industrial advantage over the other assayed formulations, since the stability of these gels is of the order of four times larger

The impact of oat structure and β-glucan on in vitro lipid digestion

Oat β-glucan has been shown to play a positive role in influencing lipid and cholesterol metabolism. However, the mechanisms behind these beneficial effects are not fully understood. The purpose of the current work was to investigate some of the possible mechanisms behind the cholesterol lowering effect of oat β-glucan, and how processing of oat modulates lipolysis. β-Glucan release, and the rate and extent of lipolysis measured in the presence of different sources of oat β-glucan, were investigated during gastrointestinal digestion. Only a fraction of the original β-glucan content was released during digestion. Oat flakes and flour appeared to have a more significant effect on lipolysis than purified β-glucan. These findings show that the positive action of β-glucan is likely to involve complex processes and interactions with the food matrix. This work also highlights the importance of considering the structure and physicochemical properties of foods, and not just the nutrient content