Classical Symmetries of Some Two-Dimensional Models Coupled to Gravity

This paper is a sequel to one in which we examined the affine symmetry algebras of arbitrary classical principal chiral models and symmetric space models in two dimensions. It examines the extension of those results in the presence of gravity. The main result is that even though the symmetry transformations of the fields depend on the gravitational background, the symmetry algebras of these classical theories are completely unchanged by the presence of arbitrary gravitational backgrounds. On the other hand, we are unable to generalize the Virasoro symmetries of the flat-space theories to theories with gravity.Comment: 22 pages, late

What mediates the impact of response alternatives on behavioral reports?

Wie vorausgegangene Forschungsergebnisse zeigen, gehen Befragte davon aus, daß die Spannbreite vorgegebener Antwortalternativen Kenntnisse des Forschers über die Verteilung von Meinungen oder Verhaltensweisen in der Bevölkerung widerspiegeln. Diese Annahme kann das Antwortverhalten in zwei Richtungen beeinflussen. Die Befragten können entweder die spannbreite der vorgegebenen Antwortalternativen als Bezugsrahmen für die Einschätzung der Häufigkeit eines eigenen Verhaltens verwenden oder im Rahmen der Skala extrem erscheinende Häufigkeiten nicht angeben. Es wurden zwei Experimente durchgeführt, deren Ergebnisse für die 'Bezugsrahmen-Hypothese' sprechen. (WZübers)'Previous research demonstrated that respondents assume that the range of precoded response alternatives reflects the researcher's konwledge of the distribution of opinions or behaviors in the population. This assumption may influence respondents' reports in two ways: Respondents may either use the range of the response alternatives as a frame of reference in estimating their own behavioral frequencies, or they may be reluctant to report frequencies that appear extreme in the context of the scale. Two experiments were conducted to differentiate between the frame of reference and the social desirability hypothesis. The results of both studies favor the frame of reference hypothesis.' (author's abstract

E_{10} Symmetry in One-dimensional Supergravity

We consider dimensional reduction of the eleven-dimensional supergravity to less than four dimensions. The three-dimensional $E_{8(+8)}/SO(16)$ nonlinear sigma model is derived by direct dimensional reduction from eleven dimensions. In two dimensions we explicitly check that the Matzner-Misner-type $SL(2,R)$ symmetry, together with the $E_8$, satisfies the generating relations of $E_9$ under the generalized Geroch compatibility (hypersurface-orthogonality) condition. We further show that an extra $SL(2,R)$ symmetry, which is newly present upon reduction to one dimension, extends the symmetry algebra to a real form of $E_{10}$. The new $SL(2,R)$ acts on certain plane wave solutions propagating at the speed of light. To show that this $SL(2,R)$ cannot be expressed in terms of the old $E_9$ but truly enlarges the symmetry, we compactify the final two dimensions on a two-torus and confirm that it changes the conformal structure of this two-torus.Comment: 33 pages, 3 figures. The action of the Chevalley generators of SL(2,R)_8 is corrected. Commutativity of SL(2,R)_0 and SL(2,R)_8 is checked in detail. The generalized Geroch compatibility (hypersurface-orthogonality) condition is derive

Infinite-Dimensional Symmetries of Two-Dimensional Coset Models

It has long been appreciated that the toroidal reduction of any gravity or supergravity to two dimensions gives rise to a scalar coset theory exhibiting an infinite-dimensional global symmetry. This symmetry is an extension of the finite-dimensional symmetry G in three dimensions, after performing a further circle reduction. There has not been universal agreement as to exactly what the extended symmetry algebra is, with different arguments seemingly concluding either that it is $\hat G$, the affine Kac-Moody extension of G, or else a subalgebra thereof. Exceptional in the literature for its explicit and transparent exposition is the extremely lucid discussion by Schwarz, which we take as our starting point for studying the simpler situation of two-dimensional flat-space sigma models, which nonetheless capture all the essential details. We arrive at the conclusion that the full symmetry is described by the Kac-Moody algebra G, although truncations to subalgebras, such as the one obtained by Schwarz, can be considered too. We then consider the explicit example of the SL(2,R)/O(2) coset, and relate Schwarz's approach to an earlier discussion that goes back to the work of Geroch.Comment: Typos corrected, some reorganisation; 36 page

Modelling the Effect of Process Parameters on the Wet Extrusion and Spheronisation of High-Loaded Nicotinamide Pellets Using a Quality by Design Approach

Open access articleThe aim of the present study was to develop an alternative process to spray granulation in order to prepare high loaded spherical nicotinamide (NAM) pellets by wet extrusion and spheronisation. Therefore, a quality by design approach was implemented to model the effect of the process parameters of the extrusion-spheronisation process on the roundness, roughness and useable yield of the obtained pellets. The obtained results were compared to spray granulated NAM particles regarding their characteristics and their release profile in vitro after the application of an ileocolon targeted shellac coating. The wet extrusion-spheronisation process was able to form highly loaded NAM pellets (80%) with a spherical shape and a high useable yield of about 90%. However, the water content range was rather narrow between 24.7% and 21.3%. The design of experiments (DoE), showed that the spheronisation conditions speed, time and load had a greater impact on the quality attributes of the pellets than the extrusion conditions screw design, screw speed and solid feed rate (hopper speed). The best results were obtained using a low load (15 g) combined with a high rotation speed (900 m/min) and a low time (3–3.5 min). In comparison to spray granulated NAM pellets, the extruded NAM pellets resulted in a higher roughness and a higher useable yield (63% vs. 92%). Finally, the coating and dissolution test showed that the extruded and spheronised pellets are also suitable for a protective coating with an ileocolonic release profile. Due to its lower specific surface area, the required shellac concentration could be reduced while maintaining the release profil

Dualisation of Dualities, I

We analyse the global (rigid) symmetries that are realised on the bosonic fields of the various supergravity actions obtained from eleven-dimensional supergravity by toroidal compactification followed by the dualisation of some subset of fields. In particular, we show how the global symmetries of the action can be affected by the choice of this subset. This phenomenon occurs even with the global symmetries of the equations of motion. A striking regularity is exhibited by the series of theories obtained respectively without any dualisation, with the dualisation of only the Ramond-Ramond fields of the type IIA theory, with full dualisation to lowest degree forms, and finally for certain inverse dualisations (increasing the degrees of some forms) to give the type IIB series. These theories may be called the GL_A, D, E and GL_B series respectively. It turns out that the scalar Lagrangians of the E series are sigma models on the symmetric spaces K(E_{11-D})\backslash E_{11-D} (where K(G) is the maximal compact subgroup of G) and the other three series lead to models on homogeneous spaces K(G) \backslash G\semi \R^s. These can be understood from the E series in terms of the deletion of positive roots associated with the dualised scalars, which implies a group contraction. We also propose a constrained Lagrangian version of the even dimensional theories exhibiting the full duality symmetry and begin a systematic analysis of abelian duality subalgebras.Comment: Latex, 82 pages, minor corrections and references adde

The Prevalence and Impact of Chronic Pain in Baccalaureate Nursing Students

Chronic pain is a problem because it can have a large impact on activities of daily life of people, regardless of age. Few researchers have described the prevalence and impact of chronic pain in young adults, while even fewer have done so in the United States. The purpose of this study is to determine the prevalence of chronic pain and the impact it has on daily life for undergraduate nursing students. The theoretical framework is guided on the biopsychosocial model of chronic pain. This cross-sectional, descriptive study uses convenience sampling and data collected through an online Qualtrics survey, which was embedded in three waves of recruitment emails. Self-reporting responses were collected from 80 subjects who completed a survey with a revised version of the Fibromyalgia Daily Activity Checklist scale. The study found that 30% of undergraduate nursing students surveyed experienced chronic pain. The study also found that chronic pain had a significant impact on daily life, with approximately 68% of those reporting chronic pain also reporting some level of difficulty when performing activities of daily living. This is significant for young adults, especially healthcare students and providers because working as healthcare professional can be physically demanding

Coset Symmetries in Dimensionally Reduced Bosonic String Theory

We discuss the dimensional reduction of various effective actions, particularly that of the closed Bosonic string and pure gravity, to two and three dimensions. The result for the closed Bosonic string leads to coset symmetries which are in agreement with those recently predicted and argued to be present in a new unreduced formulation of this theory. We also show that part of the Geroch group appears in the unreduced duality symmetric formulation of gravity recently proposed. We conjecture that this formulation can be extended to a non-linear realisation based on a Kac-Moody algebra which we identify. We also briefly discuss the proposed action of Bosonic M-theory.Comment: Reference adde

Die postoperative akute Nierenschädigung : eine retrospektive Betrachtung von Outcome, Risikofaktoren, Ressourcenverbrauch und Abbildung im DRG-System

Postoperative Komplikationen stellen ein großes Spektrum an Problemen im klinischen Alltag dar und erhöhen Versorgungsaufwand und -kosten der Patienten. In dieser Dissertation sollen das Outcome, der Ressourcenverbrauch und die Erlöse von Patienten mit einer postoperativen akuten Nierenschädigung betrachtet werden. Um gefährdete Patienten besser zu erkennen, wurde eine Untersuchung von Einflussfaktoren der akuten Nierenschädigung angeschlossen. Bei 10 % der Patienten des gemischt-chirurgischen Kollektivs wurde eine postoperative akute Nierenschädigung detektiert. Bereits mit Vorliegen des ersten Schweregrades waren ein schlechteres Outcome und ein höherer Ressourcenverbrauch zu verzeichnen. Diese Aspekte spiegelten sich ebenfalls in wirtschaftlicher Hinsicht wieder. Das Auftreten einer postoperativen akuten Nierenschädigung verursachte erheblich mehr Kosten für das deutsche Gesundheitssystem. Als Risikofaktoren konnten patientenspezifische Parameter (Alter, ASA-Klasse, präoperativ eingeschränkter Nierenfunktion), chirurgische Parameter (Not-/Soforteingriff, Eingriffe der Abteilungen: Herz- und Thoraxchirurgie, Allgemein- und Gefäßchirurgie, Gynäkologie, Urologie, Radiologie und Nuklearmedizin, Schnitt-Naht-Zeit) und anästhesiologische Parameter (Ileuseinleitung, lumbale und thorakale Epiduralanästhesie, Hypothermie, postoperative maschinelle Beatmung) identifiziert werden. Häufigkeit und Auswirkungen der postoperativen akuten Nierenschädigung sollten auf chirurgischer und anästhesiologischer Seite Anreize bieten, Risikofaktoren zu kennen und präventive Maßnahmen durchzuführen. Eine elektronisch gestützte Detektion der akuten Nierenschädigung bietet Möglichkeiten einer frühen Diagnosestellung im Krankenhaus