228 research outputs found
On the S-wave piD-scattering length in the relativistic field theory model of the deuteron
The S-wave scattering length of the strong pion-deuteron (pi D) scattering is
calculated in the relativistic field theory model of the deuteron suggested in
[1,2].The theoretical result agrees well with the experimental data. The
important role of the Delta-resonance contribution to the elastic pi
D-scattering is confirmed.Comment: 7 pages, no figures, accepted for publication in Z. Phys.
Not the Root of the Problem-Hair Cortisol and Cortisone Do Not Mediate the Effect of Child Maltreatment on Body Mass Index.
BACKGROUND: Experiencing maltreatment during childhood exerts substantial stress on the child and increases the risk for overweight and obesity later in life. The current study tests whether hair cortisol-a measure of chronic stress-and its metabolite cortisone mediate the relation between abuse and neglect on the one hand, and body mass index (BMI) on the other. METHOD: The sample consisted of 249 participants aged 8 to 87 years (M = 36.13, SD = 19.33). We collected data on child abuse and neglect using questionnaires, measured cortisol and cortisone concentrations in hair, and BMI. In a structural model, the effects of abuse and neglect on hair cortisol, hair cortisone, and BMI were tested, as well as the covariance between hair cortisol and BMI, and hair cortisone and BMI. RESULTS: Within the sample, 23% were overweight but not obese and 14% were obese. Higher levels of experienced abuse were related to higher cortisone concentrations in hair (ÎČ = 0.24, p < .001) and higher BMI (ÎČ = 0.17, p =.04). Neglect was not related to hair cortisol, hair cortisone, or BMI. Hair cortisol and cortisone did not mediate the association between maltreatment, and BMI. Sensitivity analyses demonstrate the same pattern of results in a subsample of adult participants currently not living with their parents. However, in younger participants who were still living with their parents, the associations between abuse and cortisone (ÎČ = 0.14, p =.35) and abuse and BMI (ÎČ = 0.02, p =.92) were no longer significant. CONCLUSION: These findings confirm that experiencing abuse is related to higher BMI but suggest that hair cortisol and cortisone are not the mechanism underlying the association between child maltreatment and BMI. This is the first study to show abuse may be associated to elevated concentrations of hair cortisone-evidence of long-term alterations in chronic stress levels. Future research may benefit from exploring the effects of maltreatment on weight gain in longitudinal designs, including measures of other potential mediators such as eating as a coping mechanism, and more direct indicators of metabolic health
Intergenerational transmission of child maltreatment using a multi-informant multi-generation family design.
In the current study a three-generational design was used to investigate intergenerational transmission of child maltreatment (ITCM) using multiple sources of information on child maltreatment: mothers, fathers and children. A total of 395 individuals from 63 families reported on maltreatment. Principal Component Analysis (PCA) was used to combine data from mother, father and child about maltreatment that the child had experienced. This established components reflecting the convergent as well as the unique reports of father, mother and child on the occurrence of maltreatment. Next, we tested ITCM using the multi-informant approach and compared the results to those of two more common approaches: ITCM based on one reporter and ITCM based on different reporters from each generation. Results of our multi-informant approach showed that a component reflecting convergence between mother, father, and child reports explained most of the variance in experienced maltreatment. For abuse, intergenerational transmission was consistently found across approaches. In contrast, intergenerational transmission of neglect was only found using the perspective of a single reporter, indicating that transmission of neglect might be driven by reporter effects. In conclusion, the present results suggest that including multiple informants may be necessary to obtain more valid estimates of ITCM
Estimating the Heritability of Experiencing Child Maltreatment in an Extended Family Design
Child-driven genetic factors can contribute to negative parenting and may increase the risk of being maltreated. Experiencing childhood maltreatment may be partly heritable, but results of twin studies are mixed. In the current study, we used a cross-sectional extended family design to estimate genetic and environmental effects on experiencing child maltreatment. The sample consisted of 395 individuals (225 women; M age = 38.85 years, rangeage = 7â88 years) from 63 families with two or three participating generations. Participants were oversampled for experienced maltreatment. Self-reported experienced child maltreatment was measured using a questionnaire assessing physical and emotional abuse, and physical and emotional neglect. All maltreatment phenotypes were partly heritable with percentages for h 2 ranging from 30% (SE = 13%) for neglect to 62% (SE = 19%) for severe physical abuse. Common environmental effects (c 2) explained a statistically significant proportion of variance for all phenotypes except for the experience of severe physical abuse (c 2 = 9%, SE = 13%, p = .26). The genetic correlation between abuse and neglect was Ïg = .73 (p = .02). Common environmental variance increased as socioeconomic status (SES) decreased (p = .05), but additive genetic and unique environmental variances were constant across different levels of SES
Not the Root of the ProblemâHair Cortisol and Cortisone Do Not Mediate the Effect of Child Maltreatment on Body Mass Index
Background: Experiencing maltreatment during childhood exerts substantial stress on the child and increases the risk for overweight and obesity later in life. The current study tests whether hair cortisolâa measure of chronic stressâand its metabolite cortisone mediate the relation between abuse and neglect on the one hand, and body mass index (BMI) on the other. Method: The sample consisted of 249 participants aged 8 to 87 years (M = 36.13, SD = 19.33). We collected data on child abuse and neglect using questionnaires, measured cortisol and cortisone concentrations in hair, and BMI. In a structural model, the effects of abuse and neglect on hair cortisol, hair cortisone, and BMI were tested, as well as the covariance between hair cortisol and BMI, and hair cortisone and BMI. Results: Within the sample, 23% were overweight but not obese and 14% were obese. Higher levels of experienced abuse were related to higher cortisone concentrations in hair (ÎČ = 0.24, p <.001) and higher B
Yang-Baxter equation and reflection equations in integrable models
The definitions of the main notions related to the quantum inverse scattering
methods are given. The Yang-Baxter equation and reflection equations are
derived as consistency conditions for the factorizable scattering on the whole
line and on the half-line using the Zamolodchikov-Faddeev algebra. Due to the
vertex-IRF model correspondence the face model analogue of the ZF-algebra and
the IRF reflection equation are written down as well as the -graded and
colored algebra forms of the YBE and RE.Comment: 21 pages, Latex, Lectures in Schladming school of theoretical physics
(March 1995
Quantum field theory and Hopf algebra cohomology
We exhibit a Hopf superalgebra structure of the algebra of field operators of
quantum field theory (QFT) with the normal product. Based on this we construct
the operator product and the time-ordered product as a twist deformation in the
sense of Drinfeld. Our approach yields formulas for (perturbative) products and
expectation values that allow for a significant enhancement in computational
efficiency as compared to traditional methods. Employing Hopf algebra
cohomology sheds new light on the structure of QFT and allows the extension to
interacting (not necessarily perturbative) QFT. We give a reconstruction
theorem for time-ordered products in the spirit of Streater and Wightman and
recover the distinction between free and interacting theory from a property of
the underlying cocycle. We also demonstrate how non-trivial vacua are described
in our approach solving a problem in quantum chemistry.Comment: 39 pages, no figures, LaTeX + AMS macros; title changed, minor
corrections, references update
Peptide YY ablation in mice leads to the development of hyperinsulinaemia and obesity
Aims/hypothesis. Obese people exhibit reduced circulating peptide YY (PYY) levels, but it is unclear whether this is a consequence or cause of obesity. We therefore investigated the effect of Pyy ablation on energy homeostasis.
Methods. Body composition, i.p. glucose tolerance, food intake and hypothalamic neuropeptide expression were determined in Pyy knock-out and wild-type mice on a normal or high-fat diet. Results. Pyy knock-out significantly increased bodyweight and increased fat mass by 50% in aged females on a normal diet. Male chow-fed Pyy â/â mice were resistant to obesity but became significantly fatter and glucose-intolerant compared with wild-types when fed a high-fat diet. Pyy knock-out animals exhibited significantly elevated fasting or glucose-stimulated serum insulin concentrations vs wild-types, with no increase in basal or fasting-induced food intake. Pyy knock-out decreased or had no effect on neuropeptide Y expression in the arcuate nucleus of the hypothalamus, and significantly increased proopiomelanocortin expression in this region. Male but not female knock-outs exhibited significantly increased growth hormone-releasing hormone expression in the ventromedial hypothalamus and significantly elevated serum IGF-I and testosterone levels. This sex difference in activation of the hypothalamoâpituitary somatotrophic axis by Pyy ablation may contribute to the resistance of chow-fed male knock-outs to late-onset obesity.
Conclusions/interpretation. PYY signalling is important in the regulation of energy balance and glucose homeostasis, possibly via regulation of insulin release. Therefore reduced PYY levels may predispose to the development of obesity, particularly with ageing or under conditions of high-fat feeding
- âŠ