Giant magnons of string theory in the lambda background

The analogues of giant magnon configurations are studied on the string world sheet in the lambda background. This is a discrete deformation of the AdS(5)xS(5) background that preserves the integrability of the world sheet theory. Giant magnon solutions are generated using the dressing method and their dispersion relation is found. This reduces to the usual dyonic giant magnon dispersion relation in the appropriate limit and becomes relativistic in another limit where the lambda model becomes the generalized sine-Gordon theory of the Pohlmeyer reduction. The scattering of giant magnons is then shown in the semi-classical limit to be described by the quantum S-matrix that is a quantum group deformation of the conventional giant magnon S-matrix. It is further shown that in the small g limit, a sector of the S-matrix is related to the XXZ spin chain whose spectrum matches the spectrum of magnon bound states.Comment: 53 pages, 6 figures, final version to appear in JHE

Classical and quantum aspects of Yang-Baxter Wess-Zumino models

We investigate the integrable Yang-Baxter deformation of the 2d Principal Chiral Model with a Wess-Zumino term. For arbitrary groups, the one-loop $\beta$-functions are calculated and display a surprising connection between classical and quantum physics: the classical integrability condition is necessary to prevent new couplings being generated by renormalisation. We show these theories admit an elegant realisation of Poisson-Lie T-duality acting as a simple inversion of coupling constants. The self-dual point corresponds to the Wess-Zumino-Witten model and is the IR fixed point under RG. We address the possibility of having supersymmetric extensions of these models showing that extended supersymmetry is not possible in general

Environmental and genetic influences on early attachment

Attachment theory predicts and subsequent empirical research has amply demonstrated that individual variations in patterns of early attachment behaviour are primarily influenced by differences in sensitive responsiveness of caregivers. However, meta-analyses have shown that parenting behaviour accounts for about one third of the variance in attachment security or disorganisation. The exclusively environmental explanation has been challenged by results demonstrating some, albeit inconclusive, evidence of the effect of infant temperament. In this paper, after reviewing briefly the well-demonstrated familial and wider environmental influences, the evidence is reviewed for genetic and gene-environment interaction effects on developing early attachment relationships. Studies investigating the interaction of genes of monoamine neurotransmission with parenting environment in the course of early relationship development suggest that children's differential susceptibility to the rearing environment depends partly on genetic differences. In addition to the overview of environmental and genetic contributions to infant attachment, and especially to disorganised attachment relevant to mental health issues, the few existing studies of gene-attachment interaction effects on development of childhood behavioural problems are also reviewed. A short account of the most important methodological problems to be overcome in molecular genetic studies of psychological and psychiatric phenotypes is also given. Finally, animal research focusing on brain-structural aspects related to early care and the new, conceptually important direction of studying environmental programming of early development through epigenetic modification of gene functioning is examined in brief

D-branes in λ-deformations

We show that the geometric interpretation of D-branes in WZW models as twisted conjugacy classes persists in the $\lambda$--deformed theory. We obtain such configurations by demanding that a monodromy matrix constructed from the Lax connection of the $\lambda$--deformed theory continues to produce conserved charges in the presence of boundaries. In this way the D-brane configurations obtained correspond to ``integrable'' boundary configurations. We illustrate this with examples based on $SU(2)$ and $SL(2,\mathbb{R})$, and comment on the relation of these D-branes to both non-Abelian T-duality and Poisson-Lie T-duality. We show that the D2 supported by D0 charge in the $\lambda$--deformed theory map, under analytic continuation together with Poisson-Lie T-duality, to D3 branes in the $\eta$-deformation of the principal chiral model

Wellbeing and resilience:Mechanisms of transmission of health and risk in parents with complex mental health problems and their offspring—The WARM Study

The WARM study is a longitudinal cohort study following infants of mothers with schizophrenia, bipolar disorder, depression and control from pregnancy to infant 1 year of age. Background: Children of parents diagnosed with complex mental health problems including schizophrenia, bipolar disorder and depression, are at increased risk of developing mental health problems compared to the general population. Little is known regarding the early developmental trajectories of infants who are at ultra-high risk and in particular the balance of risk and protective factors expressed in the quality of early caregiver-interaction. Methods/Design: We are establishing a cohort of pregnant women with a lifetime diagnosis of schizophrenia, bipolar disorder, major depressive disorder and a non-psychiatric control group. Factors in the parents, the infant and the social environment will be evaluated at 1, 4, 16 and 52 weeks in terms of evolution of very early indicators of developmental risk and resilience focusing on three possible environmental transmission mechanisms: stress, maternal caregiver representation, and caregiver-infant interaction. Discussion: The study will provide data on very early risk developmental status and associated psychosocial risk factors, which will be important for developing targeted preventive interventions for infants of parents with severe mental disorder

A nationwide Belgian survey on the influence of the new oral anticoagulants dabigatran and rivaroxaban on commonly used coagulation assays

Background: The new oral anticoagulants dabigatran etexilate (direct thrombin inhibitor, Pradaxa®, Boehringer Ingelheim) and rivaroxaban (direct factor Xa inhibitor, Xarelto®, Bayer) have been in clinical use for a few years for the prevention of thromboembolic events after elective hip- or knee-replacement surgery and for the prevention of stroke and systemic embolism in patients with atrial fibrillation. Although these agents do not require monitoring, their presence can significantly influence coagulation assays, potentially leading to incorrect interpretation of test results. Aims: The Belgian national External Quality Assessment Scheme for blood coagulation organized a survey to investigate and illustrate to the clinical laboratories how these drugs affect their routine coagulation assays. Methods: All Belgian clinical laboratories routinely performing coagulation testing (n = 192) received five lyophilized plasma samples in April 2012. These samples consisted of a normal plasma pool spiked with dabigatran or rivaroxaban to the following final concentrations: 0, 100 ng/mL dabigatran, 250 ng/mL dabigatran, 120 ng/mL rivaroxaban, and 290 ng/mL rivaroxaban. The samples were purchased from Hyphen BioMed (Neuville surOise, France). Participants were requested to determine the following coagulation assays: prothrombin time (PT, seconds,% and INR), activated partial thromboplastin time (aPTT, seconds and ratio), fibrinogen and antithrombin. They were also required to mention the reagent and analyser used. Method-specific medians and robust standard deviations were calculated for all methods with ≥ 6 reported results (method of Tukey). Differences between methods were assessed by means of non parametric statistics (Wilcoxon test). Results: All but three laboratories participated in the survey (response rate of 98.4%). PT and aPTT: Both, dabigatran and rivaroxaban significantly prolonged the PT and aPTT in a concentration- and reagent-dependent manner. The PT was more influenced by rivaroxaban than by dabigatran, while the aPTT was more influenced by dabigatran than by rivaroxaban. There was a wide variation in responsiveness between reagent/instrument combinations. The PT reagents Neoplastin CI Plus and Neoplastin R (Diagnostica Stago, Asniéres sur Seine, France) were the most sensitive to rivaroxaban and the reagents Innovin and Thromborel S (Siemens, Marburg, Germany) the least sensitive. The aPTT reagents most and least sensitive to dabigatran were CK Prest (Diagnostica Stago) and Actin FSL (Siemens). Converting PT results to INR did not reduce but even increased the variability between reagents. Fibrinogen: Rivaroxaban did not influence the determination of fibrinogen but the presence of dabigatran led to a falsely reduced fibrinogen concentration when measured with a low thrombin concentration reagent. Antithrombin: The presence of dabigatran caused an overestimation of the antithrombin level when measured with an assay based on thrombin inhibition while the presence of rivaroxaban caused an overestimation of the antithrombin level when measured with an assay based on FXa inhibition. Summary/Conclusions: This study demonstrates that the influence of dabigatran and rivaroxaban on the routine coagulation assays used in Belgium largely depends on the reagent/analyser combination used and the drug concentration. All laboratories received a full report of the results in order to draw attention to the importance of careful interpretation of coagulation test results in patients taking dabigatran or rivaroxaban