155 research outputs found

    Light-induced magnetization reversal of high-anisotropy TbCo alloy films

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    Magnetization reversal using circularly polarized light provides a new way to control magnetization without any external magnetic field and has the potential to revolutionize magnetic data storage. However, in order to reach ultra-high density data storage, high anisotropy media providing thermal stability are needed. Here, we evidence all-optical magnetization switching for different TbxCo1-x ferrimagnetic alloy composition and demonstrate all-optical switching for films with anisotropy fields reaching 6 T corresponding to anisotropy constants of 3x106 ergs/cm3. Optical magnetization switching is observed only for alloys which compensation temperature can be reached through sample heating

    Disgust and implicit self-concept in women with borderline personality disorder and posttraumatic stress disorder

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    Disgust may be a key emotion and target for psychotherapeutic interventions in borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD) at explicit and implicit-automatic levels. However, automatically activated disgust reactions in individuals with these disorders have not been studied. Disgust and its correlation with childhood abuse were assessed in women with BPD, but without PTSD; women with PTSD, but without BPD; women with BPD and PTSD; and healthy women. Disgust sensitivity, anxiety and depression were measured by self-report. Implicit disgust-prone (relative to anxiety-prone) self-concept was assessed using the Implicit Association Test. Women with BPD and/or PTSD reported more disgust sensitivity than controls. The implicit self-concept among patients was more disgust-prone (relative to anxiety-prone) than in controls. Women with BPD, with PTSD, or BPD and PTSD did not differ significantly in self-reported disgust levels or implicit disgust-related self-concept. Among women with BPD and/or PTSD, current psychiatric comorbidity (major depression, anxiety disorder, eating disorder, or substance-related disorder) did not affect disgust-related variables. More severe physical abuse in childhood was associated with a more anxiety-prone (less disgust-prone) implicit self-concept. Independent of psychiatric comorbidity, disgust appears to be elevated at implicit and explicit levels in trauma-related disorders. Psychotherapeutic approaches to address disgust should take implicit processes into accoun

    Detecting inhomogeneous chiral condensation from the bosonic two-point function in the (1+1)(1 + 1)-dimensional Gross-Neveu model in the mean-field approximation

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    The phase diagram of the (1+1)(1 + 1)-dimensional Gross-Neveu model is reanalyzed for (non-)zero chemical potential and (non-)zero temperature within the mean-field approximation. By investigating the momentum dependence of the bosonic two-point function, the well-known second-order phase transition from the Z2\mathbb{Z}_2 symmetric phase to the so-called inhomogeneous phase is detected. In the latter phase the chiral condensate is periodically varying in space and translational invariance is broken. This work is a proof of concept study that confirms that it is possible to correctly localize second-order phase transition lines between phases without condensation and phases of spatially inhomogeneous condensation via a stability analysis of the homogeneous phase. To complement other works relying on this technique, the stability analysis is explained in detail and its limitations and successes are discussed in context of the Gross-Neveu model. Additionally, we present explicit results for the bosonic wave-function renormalization in the mean-field approximation, which is extracted analytically from the bosonic two-point function. We find regions -- a so-called moat regime -- where the wave function renormalization is negative accompanying the inhomogeneous phase as expected.Comment: 27 pages (main text 20, appendix 7), 2 tables, 13 figures (plot data included in arXiv source file); Updated, published versio

    Life within a limited radius: Investigating activity space in women with a history of child abuse using global positioning system tracking

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    Early experiences of childhood sexual or physical abuse are often associated with functional impairments, reduced well-being and interpersonal problems in adulthood. Prior studies have addressed whether the traumatic experience itself or adult psychopathology is linked to these limitations. To approach this question, individuals with posttraumatic stress disorder (PTSD) and healthy individuals with and without a history of child abuse were investigated. We used global positioning system (GPS) tracking to study temporal and spatial limitations in the participants’ real-life activity space over the course of one week. The sample consisted of 228 female participants: 150 women with PTSD and emotional instability with a history of child abuse, 35 mentally healthy women with a history of child abuse (healthy trauma controls, HTC) and 43 mentally healthy women without any traumatic experiences in their past (healthy controls, HC). Both traumatized groups—i.e. the PTSD and the HTC group—had smaller movement radii than the HC group on the weekends, but neither spent significantly less time away from home than HC. Some differences between PTSD and HC in movement radius seem to be related to correlates of PTSD psychopathology, like depression and physical health. Yet group differences between HTC and HC in movement radius remained even when contextual and individual health variables were included in the model, indicating specific effects of traumatic experiences on activity space. Experiences of child abuse could limit activity space later in life, regardless of whether PTSD develops.Peer Reviewe

    Billiard Systems in Three Dimensions: The Boundary Integral Equation and the Trace Formula

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    We derive semiclassical contributions of periodic orbits from a boundary integral equation for three-dimensional billiard systems. We use an iterative method that keeps track of the composition of the stability matrix and the Maslov index as an orbit is traversed. Results are given for isolated periodic orbits and rotationally invariant families of periodic orbits in axially symmetric billiard systems. A practical method for determining the stability matrix and the Maslov index is described.Comment: LaTeX, 19 page

    A research programme to evaluate DBT-PTSD, a modular treatment approach for Complex PTSD after childhood abuse

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    Background: Posttraumatic stress disorder (PTSD) after childhood abuse (CA) is often related to severe co-occurring psychopathology, such as symptoms of borderline personality disorder (BPD). The ICD-11 has included Complex PTSD as a new diagnosis, which is defined by PTSD symptoms plus disturbances in emotion regulation, self-concept, and interpersonal relationships. Unfortunately, the empirical database on psychosocial treatments for survivors of CA is quite limited. Furthermore, the few existing studies often have either excluded subjects with self-harm behaviour and suicidal ideation — which is common behaviour in subjects suffering from Complex PTSD. Thus, researchers are still trying to identify efficacious treatment programmes for this group of patients. We have designed DBT-PTSD to meet the specific needs of patients with Complex PTSD. The treatment programme is based on the rules and principles of dialectical behavioural therapy (DBT), and adds interventions derived from cognitive behavioural therapy, acceptance and commitment therapy and compassion-focused therapy. DBT-PTSD can be provided as a comprehensive residential programme or as an outpatient programme. The effects of the residential programme were evaluated in a randomised controlled trial. Data revealed significant reduction of posttraumatic symptoms, with large between-group effect sizes when compared to a treatment-as-usual wait list condition (Cohen’s d = 1.5). The first aim of this project on hand is to evaluate the efficacy of the outpatient DBT-PTSD programme. The second aim is to identify the major therapeutic variables mediating treatment efficacy. The third aim is to study neural mechanisms and treatment sensitivity of two frequent sequelae of PTSD after CA: intrusions and dissociation. Methods: To address these questions, we include female patients who experienced CA and who fulfil DSM-5 criteria for PTSD plus borderline features, including criteria for severe emotion dysregulation. The study is funded by the German Federal Ministry of Education and Research, and started in 2014. Participants are randomised to outpatient psychotherapy with either DBT-PTSD or Cognitive Processing Therapy. Formal power analysis revealed a minimum of 180 patients to be recruited. The primary outcome is the change on the Clinician-Administered PTSD Scale for DSM-5. Discussion: The expected results will be a major step forward in establishing empirically supported psychological treatments for survivors of CA suffering from Complex PTSD. Trial registration: German Clinical Trials Register, registration number DRKS00005578, date of registration 19 December 2013

    Effect of Age of Infusion Site and Type of Rapid-Acting Analog on Pharmacodynamic Parameters of Insulin Boluses in Youth With Type 1 Diabetes Receiving Insulin Pump Therapy

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    OBJECTIVE—The purpose of this study was to examine the effect of type of insulin analog and age of insertion site on the pharmacodynamic characteristics of a standard insulin bolus in youth with type 1 diabetes receiving insulin pump therapy

    Effectiveness of a single-session early psychological intervention for children after road traffic accidents: a randomised controlled trial

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    BACKGROUND: Road traffic accidents (RTAs) are the leading health threat to children in Europe, resulting in 355,000 injuries annually. Because children can suffer significant and long-term mental health problems following RTAs, there is considerable interest in the development of early psychological interventions. To date, the research in this field is scarce, and currently no evidence-based recommendations can be made. METHODS: To evaluate the effectiveness of a single-session early psychological intervention, 99 children age 7-16 were randomly assigned to an intervention or control group. The manualised intervention was provided to the child and at least one parent around 10 days after the child's involvement in an RTA. It included reconstruction of the accident using drawings and accident-related toys, and psychoeducation. All of the children were interviewed at 10 days, 2 months and 6 months after the accident. Parents filled in questionnaires. Standardised instruments were used to assess acute stress disorder (ASD), posttraumatic stress disorder (PTSD), depressive symptoms and behavioural problems. RESULTS: The children of the two study groups showed no significant differences concerning posttraumatic symptoms and other outcome variables at 2 or at 6 months. Interestingly, analyses showed a significant intervention x age-group effect, indicating that for preadolescent children the intervention was effective in decreasing depressive symptoms and behavioural problems. CONCLUSIONS: This study is the first to show a beneficial effect of a single-session early psychological intervention after RTA in preadolescent children. Therefore, an age-specific approach in an early stage after RTAs may be a promising way for further research. Younger children can benefit from the intervention evaluated here. However, these results have to be interpreted with caution, because of small subgroup sizes. Future studies are needed to examine specific approaches for children and adolescents. Also, the intervention evaluated here needs to be studied in other groups of traumatised children. TRIAL REGISTRATION: Clinical Trial Registry: ClinicalTrials.gov: NCT00296842
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