352 research outputs found

    On time and the quantum-to-classical transition in Jordan-Brans-Dicke quantum gravity

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    Any quantum theory of gravity which treats the gravitational constant as a dynamical variable has to address the issue of superpositions of states corresponding to different eigenvalues. We show how the unobservability of such superpositions can be explained through the interaction with other gravitational degrees of freedom (decoherence). The formal framework is canonically quantized Jordan-Brans-Dicke theory. We discuss the concepts of intrinsic time and semiclassical time as well as the possibility of tunneling into regions corresponding to a negative gravitational constant. We calculate the reduced density matrix of the Jordan-Brans-Dicke field and show that the off-diagonal elements can be sufficiently suppressed to be consistent with experiments. The possible relevance of this mechanism for structure formation in extended inflation is briefly discussed.Comment: 10 pages, Latex, ZU-TH 15/93, BUTP-93/1

    Canopy fruit location can affect olive oil quality in Arbequina hedgerow orchards

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    The effect of location of fruit in canopies of hedgerow olive trees (Olea europaea L., cv. ‘Arbequina’) on quality of virgin oil was tested by analyzing oils extracted from different height layers and faces of 9 olive hedgerows (6 North-South oriented and 3 East-West). Although sensory attributes were not different other oil quality parameters may be significantly modified by fruit position. In some hedgerows, oils extracted from fruits harvested from higher layers exhibited significantly higher stability against oxidation, along with higher palmitic acid, linoleic acid and phenol contents, but lower oleic acid content. Oils extracted from fruits harvested from East and North facing hedgerows oriented North-South and East-West, respectively, exhibited higher oleic contents and lower saturated and polyunsaturated fatty acid contents. The mean phenol content of oils extracted from fruits from a North-South oriented hedgerow was significantly greater from one of the East-West oriented hedgerows. These findings may be relevant for the design of future olive hedgerows destined for olive oil production

    Scalar fields in an anisotropic closed universe

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    We study in this article a class of homogeneous, but anisotropic cosmological models in which shear viscosity is included. Within the matter content we consider a component (the quintessence component) determined by the barotropic equations of state, p=αρp=\alpha \rho, with α<0\alpha < 0. We establish conditions under which a closed axisymmetrical cosmological model may look flat al low redshift.Comment: 6 pages, Latex, 2 figures, accepted in Phys. Rev.

    Eficacia de una estrategia combinada para mejorar el control del colesterol unido a lipoproteínas de baja densidad en pacientes con hipercolesterolemia. Ensayo clínico aleatorizado

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    Introducción y objetivos: Intervenciones diferentes pueden mejorar el control del colesterol unido a lipoproteínas de baja densidad (cLDL). El objetivo principal era evaluar la eficacia de una intervención combinada para mejorar el control del cLDL de pacientes con hipercolesterolemia. También se evaluó su eficacia para mejorar el cumplimiento (farmacológico, dieta y ejercicio). Métodos: Ensayo clínico aleatorizado, de grupos paralelos y multicéntrico (atención primaria) que incluyó a 358 adultos diagnosticados de hipercolesterolemia con tratamiento previo farmacológico o no. Se comparó a 178 sujetos que recibieron intervención combinada (material escrito, tarjetas autocumplimentadas y mensajes al móvil) frente a 178 controles. La variable principal de resultado fue la proporción de sujetos con adecuado control del cLDL (valores recomendados en las guías europeas de dislipemias y riesgo cardiovascular) a los 24 meses. Resultados: El grupo de intervención mostró una reducción media del cLDL significativamente superior a los 24 meses respecto al control, 23, 8 mg/dl (IC95%, 17, 5-30, 1) y 14, 6 mg/dl (IC95%, 8, 9-20, 4), respectivamente (p = 0, 034). El promedio de la reducción del cLDL fue del 13, 1 ± 28, 6%. La proporción de sujetos con adecuado control al año fue significativamente superior en el grupo de intervención (43, 7 frente a 30, 1%; p = 0, 011; RR = 1, 46). En el grupo de intervención, el cumplimiento farmacológico fue significativamente superior (77, 2 frente a 64, 1%; p = 0, 029) y de la práctica de ejercicio (64, 9 frente a 35, 8%; p < 0, 001), aunque no de la dieta. Conclusiones: La intervención combinada consigue una reducción significativa de las cifras de cLDL (superior al 13% al cabo de 2 años) y mejora el grado de control de pacientes con hipercolesterolemia al año. Introduction and objectives: Several interventions can improve low-density lipoprotein cholesterol (LDL-C) control. Our main objective was to evaluate the efficacy of a combined intervention to improve LDL-C control in patients with hypercholesterolemia. The study also assessed the efficacy of the intervention in improving adherence (pharmacological, diet, and exercise). Methods: A multicenter, parallel group, randomized clinical trial (primary care) was conducted in 358 adults diagnosed with hypercholesterolemia, whether receiving prior drug therapy or not. We compared 178 participants who received the combined intervention (written material, self-completed registration cards, and messages to mobile telephones) with 178 controls. The main outcome variable was the proportion of participants with adequate LDL-C control (target levels of the European guidelines on dyslipidemia and cardiovascular risk) at 24 months. Results: At 24 months, the mean reduction in LDL-C was significantly higher in the intervention group (23.8 mg/dL [95%CI, 17.5-30.1]) than in the control group (14.6 mg/dL [95%CI, 8.9-20.4]; P = .034). The mean LDL-C decrease was 13.1% +/- 28.6%. At 1 year, the proportion of participants with adequate control was significantly higher in the intervention group than in the control group (43.7% vs 30.1%; P = .011; RR, 1.46). Adherence was significantly higher in the intervention group, both to drug therapy (77.2% vs 64.1%; P = .029) and exercise (64.9% vs 35.8; P < .001), but not to diet. Conclusions: The combined intervention significantly reduced LDL-C (by more than 13% at 2 years) and improved the degree of LDL-C control in patients with hypercholesterolemia at 1 year

    Predictive value of serum ferritin in combination with alanine aminotransferase and glucose levels for noninvasive assessment of NAFLD: Fatty liver in obesity (FLiO) study

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    The identification of affordable noninvasive biomarkers for the diagnosis and characterization of nonalcoholic fatty liver disease (NAFLD) is a major challenge for the research community. This study aimed to explore the usefulness of ferritin as a proxy biomarker of NAFLD condition, alone or in combination with other routine biochemical parameters. Subjects with overweight/obesity and ultrasound-confirmed liver steatosis (n = 112) from the Fatty Liver in Obesity (FLiO) study were assessed. The hepatic evaluation considered magnetic resonance imaging, ultrasonography, and credited routine blood liver biomarkers. Anthropometry and body composition, dietary intake (by means of a validated 137-item food frequency questionnaire), and specific biochemical markers were also determined. Serum ferritin levels were analyzed using a chemiluminescent microparticle immunoassay kit. Lower serum ferritin concentrations were associated with general better liver health and nutritional status. The evaluation of ferritin as a surrogate of liver damage by means of quantile regression analyses showed a positive association with alanine aminotransferase (ALT) (β = 19.21; p ≤ 0.001), liver fat content (β = 8.70; p = 0.008), and hepatic iron (β = 3.76; p ≤ 0.001), after adjusting for potential confounders. In receiver operating characteristic (ROC) analyses, the panel combination of blood ferritin, glucose, and ALT showed the best prediction for liver fat mass (area under the curve (AUC) 0.82). A combination of ferritin and ALT showed the higher predictive ability for estimating liver iron content (AUC 0.73). This investigation demonstrated the association of serum ferritin with liver health as well as with glucose and lipid metabolism markers in subjects with NAFLD. Current findings led to the identification of ferritin as a potential noninvasive predictive biomarker of NAFLD, whose surrogate value increased when combined with other routine biochemical measurements (glucose/ALT)

    Association of the SH2B1 rs7359397 gene polymorphism with steatosis severity in subjects with obesity and non-alcoholic fatty liver disease

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    Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver disease worldwide. Some genetic variants might be involved in the progression of this disease. The study hypothesized that individuals with the rs7359397 T allele have a higher risk of developing severe stages of NAFLD compared with non-carriers where dietary intake according to genotypes could have a key role on the pathogenesis of the disease. SH2B1 genetic variant was genotyped in 110 overweight/obese subjects with NAFLD. Imaging techniques, lipidomic analysis and blood liver biomarkers were performed. Body composition, general biochemical and dietary variables were also determined. The SH2B1 risk genotype was associated with higher HOMA-IR p equal 0.001; and Fatty Liver Index (FLI) p equal 0.032. Higher protein consumption (p equal 0.028), less mono-unsaturated fatty acid and fiber intake (p equal 0.045 and p equal 0.049, respectively), was also referred to in risk allele genotype. Lipidomic analysis showed that T allele carriers presented a higher frequency of non-alcoholic steatohepatitis (NASH) (69.1/100 vs. 44.4/100; p equal 0.006). In the genotype risk group, adjusted logistic regression models indicated a higher risk of developing an advanced stage of NAFLD measured by FLI (OR 2.91) and ultrasonography (OR 4.15). Multinomial logistic regression models showed that risk allele carriers had higher liver fat accumulation risk (RRR 3.93) and an increased risk of NASH (RRR 7.88). Consequently, subjects carrying the T allele were associated with a higher risk of developing a severe stage of NAFLD. These results support the importance of considering genetic predisposition in combination with a healthy dietary pattern in the personalized evaluation and management of NAFLD

    X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

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    Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern

    Morbid liver manifestations are intrinsically bound to metabolic syndrome and nutrient intake based on a machine-learning cluster analysis

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    Metabolic syndrome (MetS) is one of the most important medical problems around the world. Identification of patient ' s singular characteristic could help to reduce the clinical impact and facilitate individualized management. This study aimed to categorize MetS patients using phenotypical and clinical variables habitually collected during health check-ups of individuals considered to have high cardiovascular risk. The selected markers to categorize MetS participants included anthropometric variables as well as clinical data, biochemical parameters and prescribed pharmacological treatment. An exploratory factor analysis was carried out with a subsequent hierarchical cluster analysis using the z-scores from factor analysis. The first step identified three different factors. The first was determined by hypercholesterolemia and associated treatments, the second factor exhibited glycemic disorders and accompanying treatments and the third factor was characterized by hepatic enzymes. Subsequently four clusters of patients were identified, where cluster 1 was characterized by glucose disorders and treatments, cluster 2 presented mild MetS, cluster 3 presented exacerbated levels of hepatic enzymes and cluster 4 highlighted cholesterol and its associated treatments Interestingly, the liver status related cluster was characterized by higher protein consumption and cluster 4 with low polyunsaturated fatty acid intake. This research emphasized the potential clinical relevance of hepatic impairments in addition to MetS traditional characterization for precision and personalized management of MetS patients

    The genomics of ecological flexibility, large brains, and long lives in capuchin monkeys revealed with fecalFACS

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    Ecological flexibility, extended lifespans, and large brains have long intrigued evolutionary biologists, and comparative genomics offers an efficient and effective tool for generating new insights into the evolution of such traits. Studies of capuchin monkeys are particularly well situated to shed light on the selective pressures and genetic underpinnings of local adaptation to diverse habitats, longevity, and brain development. Distributed widely across Central and South America, they are inventive and extractive foragers, known for their sensorimotor intelligence. Capuchins have among the largest relative brain size of any monkey and a lifespan that exceeds 50 y, despite their small (3 to 5 kg) body size. We assemble and annotate a de novo reference genome for Through high-depth sequencing of DNA derived from blood, various tissues, and feces via fluorescence-activated cell sorting (fecalFACS) to isolate monkey epithelial cells, we compared genomes of capuchin populations from tropical dry forests and lowland rainforests and identified population divergence in genes involved in water balance, kidney function, and metabolism. Through a comparative genomics approach spanning a wide diversity of mammals, we identified genes under positive selection associated with longevity and brain development. Additionally, we provide a technological advancement in the use of noninvasive genomics for studies of free-ranging mammals. Our intra- and interspecific comparative study of capuchin genomics provides insights into processes underlying local adaptation to diverse and physiologically challenging environments, as well as the molecular basis of brain evolution and longevity. [Abstract copyright: Copyright © 2021 the Author(s). Published by PNAS.
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