21 research outputs found

    Aspects of hairy black holes in spontaneously-broken Einstein-Yang-Mills systems: Stability analysis and Entropy considerations

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    We analyze (3+1)-dimensional black-hole space-times in spontaneously broken Yang-Mills gauge theories that have been recently presented as candidates for an evasion of the scalar-no-hair theorem. Although we show that in principle the conditions for the no-hair theorem do not apply to this case, however we prove that the `spirit' of the theorem is not violated, in the sense that there exist instabilities, in both the sphaleron and gravitational sectors. The instability analysis of the sphaleron sector, which was expected to be unstable for topological reasons, is performed by means of a variational method. As shown, there exist modes in this sector that are unstable against linear perturbations. Instabilities exist also in the gravitational sector. A method for counting the gravitational unstable modes, which utilizes a catastrophe-theoretic approach is presented. The r\^ole of the catastrophe functional is played by the mass functional of the black hole. The Higgs vacuum expectation value (v.e.v.) is used as a control parameter, having a critical value beyond which instabilities are turned on. The (stable) Schwarzschild solution is then understood from this point of view. The catastrophe-theory appproach facilitates enormously a universal stability study of non-Abelian black holes, which goes beyond linearized perturbations. Some elementary entropy considerations are also presented...Comment: Latex file, 50 pages, 2 figures (included as PS files at the end: plot1.ps, plot2.ps

    Differential expression and distribution of placental glutathione peroxidases 1, 3 and 4 in normal and preeclamptic pregnancy

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    Preeclampsia is a pregnancy-specific condition affecting 2-7% of women and a leading cause of perinatal and maternal morbidity and mortality; it may also predispose the mother and fetus to increased risks of adult cardiovascular disease. The selenoprotein glutathione peroxidases (GPxs) have critical roles in regulating antioxidant status. Objectives, study design and main outcome measures: Immunohistochemical measurements of GPx 1, GPx3 and GPx4 protein expression were performed on samples taken from three standardised sampling sites between the cord insertion and the periphery of the placenta from 12 normotensive, and 12 preeclamptic women to establish if their expression differed between sampling sites. Total GPx activities were also examined from the three sampling sites of these placentae. Results: There were highly significant reductions in overall immunohistochemical staining of all 3 GPxs in the preeclampsia compared to normotensive placentae (GPx1: P = 0.016; GPx3: P = 0.003; GPx4: P < 0.001). Furthermore, graded differences in expression between the standardised placental sampling sites were also found for GPx3 (higher in the inner region, P = 0.05) and GPx4 (higher in the periphery, P = 0.02) but not GPx1. Placental GPx enzyme activity was also significantly reduced in tissue from preeclamptic women as compared to normotensive women (P = 0.007; the difference was more pronounced nearest the cord insertion). Conclusions: We have shown highly significant reductions in expression of all three major classes of GPx in placentae from women with preeclampsia, and distribution gradients in activity, which may relate to the differential oxygenation of regions of the placenta

    Colina e betaína em rações purificadas na nutrição da tilápia do Nilo (Oreochromis niloticus) Choline and betaine in purified diets for Nile tilapia (Oreochromis niloticus)

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    Problemas metabólicos observados em produções intensivas de tilápias do Nilo (Oreochromis niloticus) têm sido relacionados à deficiência de colina nas rações. Com o objetivo de avaliar o efeito da suplementação dietética da colina na nutrição da espécie, rações purificadas contendo 0; 375; 750; 1.125; 1.500 ou 1.875 mg de cloreto de colina por kg, foram administradas ad libitum por 42 dias a tilápias do Nilo (5,09 ± 0,14 g), estocados em gaiolas de PVC atóxico (volume = 60 L), alojadas em caixas de polipropileno de 1000 L, em ambiente com condições controladas de temperatura e luminosidade, num delineamento experimental em blocos incompletos casualizados, com três parcelas por bloco (n=5). O ganho de peso (GDP) e o índice de conversão alimentar (ICA) de todos os tratamentos foram superiores ao controle. Não foram observadas diferenças para a quantidade de lipídios no fígado e tecido corporal, e sobrevivência (S%). Num segundo experimento, os peixes foram alimentados com rações suplementadas com 1.250 ou 2.500 mg de cloreto de colina por kg; ou 1.000; 2.000 ou 3.000 mg de betaína por kg. Não foram observadas diferenças significativas para S% e acúmulo de lipídeos hepáticos ou corporais; o ICA e GDP dos tratamentos suplementados com colina foram superiores aos dos tratamentos suplementados com betaína, mas não diferiram entre si. Níveis de suplementação superiores a 375 mg de cloreto de colina por kg de alimento melhoram o ICA e o GDP da tilápia do Nilo, mas a betaína não substitui efetivamente a colina em rações para a espécie.<br>Metabolic problems detected in intensively raised Nile tilapia (Oreochromis niloticus) are credited to possible sub-supplementation of coline in commercial feeds. To investigate the utilization of choline and betaine as feed supplement for the Nile tilapia, groups of 10 fingerlings (5.09 ± 0.14 g) stocked in 30 PVC cages (60 L), kept under controlled environmental conditions inside 1000-L plastic pools, were fed to satiation, for 42 days, with purified diets supplemented with 0, 375, 750, 1125, 1500 or 1875 mg of choline chloride per kg of feed. Trial was set up in an incomplete, totally randomized block design (n=5). There were no significant differences among treatments for total body and liver lipid contents, and survival rate (S%); there were significant differences for weight gain (WG) and food conversion ratio (FCR) between the control and all the other treatments, but not between supplementation levels. A second trial (52 days) evaluated the effects of higher rates of choline -- 1250 or 2500 mg per kg of feed, and the substitution of choline by betaine in the diets -- 1000, 2000 or 3000 mg of betaine per kg of feed. There were no significant differences among treatments for total body and liver lipid contents, and S%, but the FCR and WG of fish fed betaine-supplemented and control diets were significantly worse. There were no differences on the performance among groups fed the choline-supplemented diets. Supplementation of 375 mg of choline per kg of feed met nutritional requirements of Nile tilapia, and betaine did not substitute choline effectively in diets for the species

    Relationships of maternal body mass index and plasma biomarkers with childhood body mass index and adiposity at 6 years; the Children of SCOPE study

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    Background: Maternal obesity has been implicated in the origins of childhood obesity through a sub-optimal environment in-utero. Objective: We examined relationships of maternal early pregnancy body mass index (BMI), overweight/obesity and plasma biomarkers of obesity, inflammation, insulin resistance and placental function with measures of childhood BMI and adiposity.Methods: BMI z-score, sum of skinfold thicknesses (SST), body fat percentage (BFP, by bioelectrical impedance), waist, arm and hip circumferences were measured in 1,173 6-year-old children of nulliparous pregnant women in the SCOPE study, New Zealand. Relationships of maternal early pregnancy (15 weeks’ gestation) BMI and biomarkers with these childhood anthropometric measures were assessed by linear regression, with appropriate adjustment.Results: 28.1% of mothers were overweight and 10.1% obese; compared with normal weight mothers, the BFP of their children were 5.3% higher [0.16 SD (95% CI 0.04 to 0.29) p=0.01] and 7.8% higher [0.27 (0.08 to 0.47) p=0.006] with comparable values for BMI z-score, arm, waist and hip circumferences. Early pregnancy maternal BMI and plasma placental growth factor (PlGF) were associated with higher child’s SST, BMI z-score, hip circumference and BFP. None of the metabolic or inflammatory maternal biomarkers were associated with childhood obesity. Conclusion: In this contemporary large prospective cohort study with extensive maternal/childhood phenotyping and a high prevalence of maternal overweight/obesity, we found independent relationships of maternal early pregnancy BMI with childhood BMI and adiposity, similar associations were observed with PlGF which may imply a role for placenta function in the developmental programming of childhood obesity risk

    Gene-by-activity interactions on obesity traits of 6-year-old New Zealand European children: A children of SCOPE study

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    Purpose: The decline of physical activity in children is considered an important determinant to explain the rising rates of obesity. However, this risk may be augmented in children who are genetically susceptible to increased weight gain. We hypothesized that a sedentary lifestyle and moderate activity will interact with genetic loci, resulting in differential effects in relation to obesity risk. Methods: We recruited 643 European children born to participants in the New Zealand-based Screening for Pregnancy Endpoints (SCOPE) study. Seventy gene variants were evaluated by the Sequenom assay. Interaction analyses were performed between the genetic variants and the activity type derived from actigraphy, in relation to percentage body fat. Results: We found a statistically significant association between increased proportions of sedentary activitywith increased percentage body fat scores (P = .012). The OLFM4-9568856 (P = .01) and GNPDA2-rs10938397 (P = .044) gene variants showed genotype differences with proportions of sedentary activity. Similarly, the OLFM4-9568856 (P = .021), CLOCK-rs4864548 (P = .029), and LEPR-1045895 (P = .047) showed genotype differences with proportions of moderate activity. We found evidence for unadjusted gene-by-activity interactions of SPACA3/SPRASArs16967845, PFKP-rs6602024, and SH2B1-rs7498665 on percentage body fat scores. Conclusions: These findings indicate a differential effect of physical activity in relation to obesity risk, suggesting that children genetically predisposed to increased weight gain may benefit from higher levels of moderate activity.</p
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