271 research outputs found
Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures
The development within the offshore wind sector towards more powerful turbines combined with increasing water depth for new wind parks is challenging both the designer as well as the manufacturer of bottom fixed support structures. Besides XL-monopiles, the market developed an innovative and economic jacket support structure which is based on automatically manufactured tubular joints combined with standardized pipes. Besides the improvements for a serial manufacturing process the automatically welded tubular joints show a great potential in terms of fatigue resistance e.g. due to a smooth weld geometry without sharp notches. However, these benefits are not considered yet within the fatigue design process of automatically manufactured jacket substructures according to current standards due to the lack of suitable S-N curves. Therefore, 32 axial fatigue tests on single and double-sided automatically welded tubular X-joints have been performed to determine a new hot spot stress related S-N curve. Based on these constant amplitude fatigue tests a new S-N curve equal to a FAT 126 curve was computed which implicitly includes the benefits of the automatically welding procedure. © Published under licence by IOP Publishing Ltd
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.
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
Relativistic quantum chemistry on quantum computers
Last years witnessed a remarkable interest in application of quantum
computing for solving problems in quantum chemistry more efficiently than
classical computers allow. Very recently, even first proof-of-principle
experimental realizations have been reported. However, so far only the
non-relativistic regime (i.e. Schroedinger equation) has been explored, while
it is well known that relativistic effects can be very important in chemistry.
In this letter we present the first quantum algorithm for relativistic
computations of molecular energies. We show how to efficiently solve the
eigenproblem of the Dirac-Coulomb Hamiltonian on a quantum computer and
demonstrate the functionality of the proposed procedure by numerical
simulations of computations of the spin-orbit splitting in the SbH molecule.
Finally, we propose quantum circuits with 3 qubits and 9 or 10 CNOTs, which
implement a proof-of-principle relativistic quantum chemical calculation for
this molecule and might be suitable for an experimental realization
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
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
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
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