Integrable Approximations for Dynamical Tunneling

Generic Hamiltonian systems have a mixed phase space, where classically disjoint regions of regular and chaotic motion coexist. For many applications it is useful to approximate the regular dynamics of such a mixed system H by an integrable approximation Hreg. We present a new, iterative method to construct such integrable approximations. The method is based on the construction of an integrable approximation in action representation which is then improved in phase space by iterative applications of canonical transformations. In contrast to other known approaches, our method remains applicable to strongly non-integrable systems H. We present its application to 2D maps and 2D billiards. Based on the obtained integrable approximations we finally discuss the theoretical description of dynamical tunneling in mixed systems.Typische Hamiltonsche Systeme haben einen gemischten Phasenraum, in dem disjunkte Bereiche klassisch regulärer und chaotischer Dynamik koexistieren. Für viele Anwendungen ist es zweckmäßig, die reguläre Dynamik eines solchen gemischten Systems H durch eine integrable Näherung Hreg zu beschreiben. Wir stellen eine neue, iterative Methode vor, um solche integrablen Näherungen zu konstruieren. Diese Methode basiert auf der Konstruktion einer integrablen Näherung in Winkel-Wirkungs-Variablen, die im Phasenraum durch iterative Anwendungen kanonischer Transformationen verbessert wird. Im Gegensatz zu bisher bekannten Verfahren bleibt unsere Methode auch auf stark nichtintegrable Systeme H anwendbar. Wir demonstrieren sie anhand von 2D-Abbildungen und 2D-Billards. Mit den gewonnenen integrablen Näherungen diskutieren wir schließlich die theoretische Beschreibung von dynamischem Tunneln in gemischten Systemen

Integrable approximation of regular regions with a nonlinear resonance chain

Generic Hamiltonian systems have a mixed phase space where regions of regular and chaotic motion coexist. We present a method for constructing an integrable approximation to such regular phase-space regions including a nonlinear resonance chain. This approach generalizes the recently introduced iterative canonical transformation method. In the first step of the method a normal-form Hamiltonian with a resonance chain is adapted such that actions and frequencies match with those of the non-integrable system. In the second step a sequence of canonical transformations is applied to the integrable approximation to match the shape of regular tori. We demonstrate the method for the generic standard map at various parameters.Comment: 10 pages, 8 figure

"Geheime Reichssache" Christianstadt : das Ende einer Kleinstadt zwischen Oder und Neiße sowie der Sprengstoff-Fabrik "Ulme"

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N-Terminale Glykierung von Proteinen in Lebensmitteln und unter physiologischen Bedingungen

Kohlenhydrate und Proteine gehören neben Wasser und Fetten zu den quantitativ bedeutendsten Grundbestandteilen biologischer Systeme und der Lebensmittel. Unter milden Bedingungen in lebenden Organismen oder unter thermischer Belastung bei der Lebensmittelverarbeitung können reduzierende Kohlenhydrate amin-katalysiert durch die Abspaltung von Wasser und Fragmentierungen des Kohlenstoffgerüsts abgebaut werden, wobei die noch reaktiveren 1,2-Dicarbonylverbindungen entstehen. Aus der Reaktion der N-α-Aminogruppe und funktioneller Gruppen der Seitenketten von Aminosäuren mit Kohlenhydraten bzw. 1,2-Dicarbonylverbindungen können stabile Endprodukte entstehen. In vivo können proteingebundene Maillard-Produkte (MRPs) aus der Reaktion mit Glucose (Amadori-Produkte) oder 1,2-Dicarbonylverbindungen (Advanced Glycation Endproducts: AGEs) entstehen. Beispielsweise ist das „N-terminale“ N-α-Fructosylderivat der β-Kette des Hämoglobins ein etablierter Parameter zur Diagnose von Diabetes mellitus (HbA1c-Wert). Diese nicht-enzymatische, posttranslationale Modifizierung von Proteinen wird allgemein als Glykierung bezeichnet und kann die Funktionalität von Proteinen beeinträchtigen. Deshalb wird untersucht, ob die Trübung der Augenlinsen, die Versteifung von Blutgefäßen oder Schädigungen von Nervenzellen durch eine erhöhte Glykierung verursacht werden. Diese Veränderungen treten im Alter und bei Stoffwechselkrankheiten wie Diabetes mellitus und Urämie auf, die durch eine erhöhte Glucosekonzentration bzw. die Anreicherung von 1,2-Dicarbonylverbindungen im Blut gekennzeichnet sind. Zwar gibt es Publikationen zum Vorkommen N-terminaler Amadori-Produkte an Hämoglobin und in Lebensmitteln, aber die Bildung N-terminaler AGEs wurde bisher nur in wenigen Studien untersucht. Deshalb waren die Bildung und das Vorkommen N-terminaler AGEs im physiologischen Modell, in Hämoglobin und in Backwaren Gegenstand der vorliegenden Arbeit. In der vorliegenden Arbeit wurde erstmals systematisch die Sequenzabhängigkeit der Bildung der Fructosylderivate bzw. der CM-Derivate in Konkurrenz zu den Glyoxal-2(1H)-Pyrazinonen am N-Terminus von Peptiden unter physiologischen und backtechnologischen Bedingungen untersucht. Dabei wurde nachgewiesen, dass die Variation der C-terminalen Aminosäure in Dipeptiden den Glykierungsgrad und das Produktspektrum erheblich beeinflusst. Mit dem konsequenten Nachweis der N-terminalen von Glyoxal und Methylglyoxal ableitbaren Carboxyalkylderivate und 2(1H)-Pyrazinone in humanen Hämoglobin wurde die Relevanz der N-terminalen Glykierung in vivo untermauert. Damit wird eine umfassendere Beurteilung des Dicarbonylstresses und der Glykierung insbesondere bei Urämikern und Diabetikern ermöglicht. Am Beispiel von Backwaren wurde für Lebensmittel gezeigt, dass unter trockenen Reaktionsbedingungen die 2(1H)-Pyrazinone und in wasserhaltigen Systemen die Carboxyalkylderivate bevorzugt zu erwarten sind

Unmet care needs in the oldest old with social loss experiences: results of a representative survey

Background: Loss experiences such as the loss of a spouse, a close relative or significant others become more likely in old age and may be strongly related to specific unmet health care needs. These unmet needs may often remain undetected and undertreated followed by a negative impact on well-being and social role functioning. The present study aims at exploring the relationship between loss experiences and specific unmet care needs in old age. Methods: As part of the study „Need assessment in the oldest old: application, psychometric examination and establishment of the German version of the Camberwell Assessment of Need for the Elderly (CANE)”, the adapted German version of the CANE was used in a population-representative telephone survey in a sample of 988 individuals aged 75+ years. Loss experiences within the last 12 months were assessed within the structured telephone survey. Descriptive and interferential statistical analyses were run in order to examine the association between loss experiences and occurring unmet care needs. Results: Overall, 29.7% of the oldest old reported at least one social loss with other relatives losses being the most frequent (12.5%), followed by non-family losses (10.7%). A significant relationship between loss experiences and a higher number of unmet care needs was observed, especially for close family losses. Other risk factors for unmet care needs were age, marital status, depression, social support and morbidity. Conclusions: This study provides, for the first time in Germany, data on the association between loss experiences and unmet needs. These findings may substantially contribute to the development of loss-specific interventions, effective treatment and health care planning for the bereaved elderly

High-K Precession modes: Axially symmetric limit of wobbling motion

The rotational band built on the high-K multi-quasiparticle state can be interpreted as a multi-phonon band of the precession mode, which represents the precessional rotation about the axis perpendicular to the direction of the intrinsic angular momentum. By using the axially symmetric limit of the random-phase-approximation (RPA) formalism developed for the nuclear wobbling motion, we study the properties of the precession modes in $^{178}$W; the excitation energies, B(E2) and B(M1) values. We show that the excitations of such a specific type of rotation can be well described by the RPA formalism, which gives a new insight to understand the wobbling motion in the triaxial superdeformed nuclei from a microscopic view point.Comment: 14 pages, 8 figures (Spelling of the authors name was wrong at the first upload, so it is corrected

Prevalence of High Resilience in Old Age and Association with Perceived Threat of COVID-19—Results from a Representative Survey

Little is known about resilience in old age and its manifestation during the COVID-19 pandemic. This study aims to estimate the prevalence of high resilience in the German old age population. We further examine the socio-demographic correlates and whether high resilience reflects on older adults’ perception of the threat posed by COVID-19. The data were derived from a representative telephone survey of n = 1005 older adults (≥65 years) during the first COVID-19 lockdown. Assessments included socio-demographic variables, the perceived threat of COVID-19, and high resilience (Brief Resilience Scale; cutoff: ≥4.31). The association between high resilience and threat from COVID-19 was analyzed using ordinal logistic regression. The study sample had a mean age (SD) of 75.5 (7.1) years, and n = 566 (56.3%) were female. The estimated prevalence of high resilience was 18.7% (95% CI = [16.3; 21.2]). High resilience was more prevalent in the younger age group and participants with higher education levels. High resilience was significantly associated with a lower perception of threat from COVID-19. The results of the representative survey in the German old age population showed that one out of five adults aged 65 years and older had high resilience. Older adults with high resilience tended to feel less threatened by COVID-19. Further research on resilience in old age is needed to support vulnerable groups in the context of care

What Comes after the Trial? An Observational Study of the Real-World Uptake of an E-Mental Health Intervention by General Practitioners to Reduce Depressive Symptoms in Their Patients

Unguided and free e-mental health platforms can offer a viable treatment and self-help option for depression. This study aims to investigate, from a public health perspective, the real-world uptake, benefits, barriers, and implementation support needed by general practitioners (GPs). The study presents data from a spin-off GP survey conducted 2.5 years subsequent to a cluster-randomized trial. A total of N = 68 GPs (intervention group (IG) GPs = 38, control group (CG) GPs = 30) participated in the survey (response rate 62.4%). Data were collected via postal questionnaires. Overall, 66.2% of the GPs were female. The average age was 51.6 years (SD = 9.4), and 48.5% of the GPs indicated that they continued (IG) or started recommending (CG) the e-mental health intervention under real-world conditions beyond the trial. A number of benefits could be identified, such as ease of integration and strengthening patient activation in disease management. Future implementation support should include providing appealing informational materials and including explainer videos. Workshops, conferences, and professional journals were identified as suitable for dissemination. Social media approaches were less appealing. Measures should be taken to make it easier for health care professionals to use an intervention after the trial and to integrate it into everyday practice