690 research outputs found

    Geometric extensions of many-particle Hardy inequalities

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    Certain many-particle Hardy inequalities are derived in a simple and systematic way using the so-called ground state representation for the Laplacian on a subdomain of Rn\mathbb{R}^n. This includes geometric extensions of the standard Hardy inequalities to involve volumes of simplices spanned by a subset of points. Clifford/multilinear algebra is employed to simplify geometric computations. These results and the techniques involved are relevant for classes of exactly solvable quantum systems such as the Calogero-Sutherland models and their higher-dimensional generalizations, as well as for membrane matrix models, and models of more complicated particle interactions of geometric character.Comment: Revised version. 28 page

    Beyond expectations: the physiological basis of sensory-enhancement of satiety

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    Background/Objectives: Consumption of high-energy beverages has been implicated as a risk factor for weight gain, yet why nutrients ingested as beverages fail to generate adequate satiety remains unclear. In general consumers do not expect drinks to be satiating, but drinks generate greater satiety when their sensory characteristics imply they may be filling. These findings challenge traditional bottom-up models of how gut-based satiety signals modify behavior to suggest that beliefs at the point of ingestion modify gut-based satiety signaling. Subjects/Methods: Healthy volunteers (n = 23) consumed four different beverages, combining an overt sensory manipulation (thin, Low Sensory, LS, or thicker and more creamy, Enhanced Sensory, ES) and covert nutrient manipulation (low energy, LE, 78kcal; high energy, HE, 267 kcal) on different days. Effects on satiety were assessed through rated appetite and levels of glucose, insulin, pancreatic polypeptide (PP) and cholesystokinin (CCK) recorded periodically over 90 minutes, and through intake at an ad libitum test lunch. Results: Intake at the test lunch and rated appetite were both altered by both the sensory and nutrient manipulations, with lowest intake and greatest suppression of hunger post-drink in the ESHE condition. Insulin increased more after HE than LE drinks, and after ES than LS drinks, while PP levels were higher after ES than LS versions. CCK levels only increased after the ESHE drink. Conclusions: These data confirm acute sensitivity of satiety after consuming a drink both to the sensory characteristics and nutrient content of the drink, and suggest that this may be at least in part due to top-down modulation of release of satiety-related gut hormones

    On the Geometry of Supersymmetric Quantum Mechanical Systems

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    We consider some simple examples of supersymmetric quantum mechanical systems and explore their possible geometric interpretation with the help of geometric aspects of real Clifford algebras. This leads to natural extensions of the considered systems to higher dimensions and more complicated potentials.Comment: 18 page

    The observed association between maternal anxiety and adolescent asthma : children of twin design suggest familial effects

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    BACKGROUND: Previous studies indicate that maternal anxiety is associated with asthma in the adolescent child, but mechanisms are unclear. OBJECTIVE: To investigate the association between maternal anxiety and maternal, self- and register-based report of asthma in the adolescent child, and whether the association remains after control of familial confounding (shared environmental and genetic factors). METHOD: From the Twin and Offspring Study of Sweden, 1691 mothers (1058 twins) and their adolescent child were included. The association between maternal self-reported anxiety (Beck Anxiety Inventory (BAI) and Karolinska Scales of Personality (KSP) somatic or psychic anxiety) and asthma based on subjective (maternal or child report) or objective (register-based diagnosis and medication) measures were analysed using logistic regression. The children-of-twins design was used to explore whether genes or environment contribute to the association. RESULTS: Maternal BAI anxiety (OR 2.02, CI 1.15-3.55) was significantly associated with adolescent asthma reported by the mother. Maternal KSP somatic anxiety (OR 1.74, CI 1.04-2.91) and psychic anxiety (OR 1.74, CI 1.05-2.86) was significantly associated with breathlessness reported by the adolescent child. In contrast, maternal anxiety was not associated with increased risk for the register-based outcomes of asthma diagnosis or medication. The results remained also after adjusting for covariates and the children-of-twins analyses which indicate that the association was due to familial confounding. CONCLUSIONS: We found some associations between maternal anxiety and subjectively reported offspring asthma or breathlessness which may be due to familial effects. A likely candidate for explaining this familial confounding is heritable personality traits associated with both anxiety and subjective measures of asthma.NonePublishe

    The relationship between the insulin-like growth factor-1 axis, weight loss, an inflammation-based score and survival in patients with inoperable non-small cell lung cancer

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    <b>Background & aims:</b> The involvement of a systemic inflammatory response, as evidenced by the Glasgow Prognostic Score (GPS), is associated with weight loss and poor outcome in patients with non-small cell lung cancer. There is good evidence that nutritional and functional decline in patients with advanced malignant disease is associated with catabolic changes in metabolism. However, defects in anabolism may also contribute towards nutritional decline in patients with cancer. The aim of the present study was to examine the relationship between IGF-1 and IGFBP-3, performance status, mGPS and survival in patients with inoperable NSCLC. <b>Methods:</b> 56 patients with inoperable NSCLC were studied. The plasma concentrations of IGF-1, IGFBP-3 and leptin were measured using ELISA and RIA. <b>Results:</b> The patients were predominantly male (61%), over 60 years old (80%), with advanced (stage III or IV) disease (98%), with a BMI≥20 (84%), an ECOG-ps of 0 or 1 (79%), a haemoglobin (59%) and white cell count (79%) in the reference range. On follow-up 43 patients died of their cancer. On univariate analysis, BMI (p<0.05), Stage (p<0.05), ECOG-ps (p<0.05), haemoglobin (p<0.05), white cell count (p<0.05) and mGPS (p<0.05) were associated with cancer specific survival. There was no association between age, sex, treatment, IGF-1, IGFBP-3, IGF-1:IGFBP-3 ratio, or leptin and cancer specific survival. With an increasing mGPS concentrations of haemoglobin (p<0.005) and IGFBP-3 (p<0.05) decreased. mGPS was not associated with either IGF-1(p>0.20), or leptin (p>0.20). <b>Conclusions:</b> In summary, the results of this study suggest that anabolism (IGF-1 axis) does not play a significant role in the relationship between nutritional and functional decline, systemic inflammation and poor survival in patients with inoperable NSCLC

    Simonsenia aveniformis sp nov (Bacillariophyceae), molecular phylogeny and systematics of the genus, and a new type of canal raphe system

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    The genus Simonsenia is reviewed and S. aveniformis described as new for science by light and electron microscopy. The new species originated from estuarine environments in southern Iberia (Atlantic coast) and was isolated into culture. In LM, Simonsenia resembles Nitzschia, with bridges (fibulae) beneath the raphe, which is marginal. It is only electron microscope (EM) examination that reveals the true structure of the raphe system, which consists of a raphe canal raised on a keel (wing), supported by rib like braces (fenestral bars) and tube-like portulae; between the portulae the keel is perforated by open windows (fenestrae). Based on the presence of portulae and a fenestrated keel, Simonsenia has been proposed to be intermediate between Bacillariaceae and Surirellaceae. However, an rbcL phylogeny revealed that Simonsenia belongs firmly in the Bacillariaceae, with which it shares a similar chloroplast arrangement, rather than in the Surirellaceae. Lack of homology between the surirelloid and simonsenioid keels is reflected in subtle differences in the morphology and ontogeny of the portulae and fenestrae. The diversity of Simonsenia has probably been underestimated, particularly in the marine environment.Polish National Science Centre in Cracow within the Maestro program [N 2012/04/A/ST10/00544]; Sciences and Technologies Foundation-FCT (Portugal) [SFRH/BD/62405/2009]info:eu-repo/semantics/publishedVersio
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