Vector product and an integrable dynamical system

We study an autonomous system of first order ordinary differential equations based on the vector product. We show that the system is completely integrable by constructing the first integrals. The connection with Nambu mechanics is established. The extension to higher dimensions is also discussed

Atomic layering at the liquid silicon surface: a first- principles simulation

We simulate the liquid silicon surface with first-principles molecular dynamics in a slab geometry. We find that the atom-density profile presents a pronounced layering, similar to those observed in low-temperature liquid metals like Ga and Hg. The depth-dependent pair correlation function shows that the effect originates from directional bonding of Si atoms at the surface, and propagates into the bulk. The layering has no major effects in the electronic and dynamical properties of the system, that are very similar to those of bulk liquid Si. To our knowledge, this is the first study of a liquid surface by first-principles molecular dynamics.Comment: 4 pages, 4 figures, submitted to PR

Transformation of the angular power spectrum of the Cosmic Microwave Background (CMB) radiation into reciprocal spaces and consequences of this approach

The formalism of solid state physics has been applied to provide an additional tool for the research of cosmological problems. It is demonstrated how this new approach could be useful in the analysis of the Cosmic Microwave Background (CMB) data. After a transformation of the anisotropy spectrum of relict radiation into a special two-fold reciprocal space it was possible to propose a simple and general description of the interaction of relict photons with the matter by a "relict radiation factor". This factor enabled us to process the transformed CMB anisotropy spectrum by a Fourier transform and thus arrive to a radial electron density distribution function (RDF) in a reciprocal space. As a consequence it was possible to estimate distances between Objects of the order ~100 [m] and the density of the ordinary matter ~1E-22 [kg.m-3]. Another analysis based on a direct calculation of the CMB radiation spectrum after its transformation into a simple reciprocal space and combined with appropriate structure modeling confirmed the cluster structure. The internal structure of Objects may be formed by Clusters distant 12 [cm], whereas the internal structure of a Cluster consisted of particles distant ~0.3 [nm]. This work points unequivocally to clustering processes and to a cluster-like structure of the matter and thus contributes to the understanding of the structure of density fluctuations. Simultaneously it sheds more light on the structure of the universe in the moment when the universe became transparent for photons. Clustering may be at the same time a new physical effect which has not been taken fully into consideration in the past. On the basis of our quantitative considerations it was possible to estimate the number of particles (protons, helium nuclei, electrons and other particles) in Objects and Clusters and the number of Clusters in an Object

German S3 guideline "actinic keratosis and cutaneous squamous cell carcinoma" – long version of the update 2023

Actinic keratosis (AK) are common lesions in light-skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence-based framework for clinical decision making, the guideline “actinic keratosis and cutaneous squamous cell carcinoma” was updated and expanded by the topics cutanepus squamous cell carcinoma in situ (Bowen’s disease) and actinic cheilitis. This guideline was developed at the highest evidence level (S3) and is aimed at dermatologists, general practitioners, ear nose and throat specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office-based settings, as well as other medical specialties, policy makers and insurance funds involved in the diagnosis and treatment of patients with AK and cSCC

Atra-Hasis

Beach soundscapes and choral works sung from portions of the ancient flood myth poem Atra-Hasis. Written nearly 4000 years ago, the Babylonian Atra-hasis is an iconic poem with an eternal message for mankind. It tells the story of how a thoughtless population weighs heavily upon the earth, such that the gods are forced to act. They first send forth a great sickness, then a great famine. But when neither of these can quiet the noise and chaos of humans, they are forced to send forth a great flood to wash away all mankind. These soundscapes and choral works were developed as part of the ‘Over Lunan’ performance project. With special thanks to Dr. Martin Worthington, Prof. Nathan Wasserman, Charlotte Steeb M.A. for generous guidance and support in working through the Bablyonian pronunciation and for filling in gaps in the text with their extensive knowledge of the latest scholarship and discoveries. Composition and Sound Design – Andrew Knight-Hill Choir – Chamber Choir from the University of St Andrews Music Centre Rebecca Black Sarah Greer James McNinch Nathanael Fagerson Ross McArthur Guy Minch Elizabeth Unsworth Wilson Jane Pettegree Choir Director – Claire Innes-Hopkins Voice – Prof. Nathan Wasserman Additional Sound Recording – Steve Urquhart Babylonian Language Consultants – Dr. Martin Worthington, Prof. Nathan Wasserman, Charlotte Steeb M.A. Atra-Hasīs Text Adapted from – W. G. Lambert; A. R. Millard (1969) Atra-ḫasīs: The Babylonian Story of the Flood. London: OUP. [with additions in bold

An agent-based approach to immune modelling

This study focuses on trying to understand why the range of experience with respect to HIV infection is so diverse, especially as regards to the latency period. The challenge is to determine what assumptions can be made about the nature of the experience of antigenic invasion and diversity that can be modelled, tested and argued plausibly. To investigate this, an agent-based approach is used to extract high-level behaviour which cannot be described analytically from the set of interaction rules at the cellular level. A prototype model encompasses local variation in baseline properties contributing to the individual disease experience and is included in a network which mimics the chain of lymphatic nodes. Dealing with massively multi-agent systems requires major computational efforts. However, parallelisation methods are a natural consequence and advantage of the multi-agent approach. These are implemented using the MPI library

The Impact of International Doctoral Capstone Experience on Occupational Therapy Clinicians\u27 Current Practice

The purpose of the study was to assess the impact of an international doctoral capstone on occupational therapy clinicians’ current practice. The study used a cross-sectional descriptive online survey design with qualitative elements with 26 occupational therapy graduates. All participants identified as female and the majority were 25-34 years old. Participants reported that the international doctorate capstone experience positively impacted their cultural competence and professional growth. Qualitative outcomes supported these findings through three themes on culture, building rapport with patients, and professional growth. This study suggests that an international doctoral capstone experience is an important way for occupational therapy students to be prepared to become culturally competent clinicians and advance their professional skills. Limitations of the study included a convenience sample of occupational therapy alumni who graduated from Creighton University and using a non-validated survey instrument. Future studies need to use a representative sample and examine the cultural competence and professional growth of occupational therapy students who did not complete an international capstone project

Fluencia a alta temperatura de compuestos alúmina-circona

Se ha estudiado la microestructura y la respuesta mecánica en compresión a alta temperatura de dos cerámicos de alúmina reforzada con circona (ZTA), fabricados mediante mezcla de polvos y mediante sol-gel con precursores de circona, para determinar la influencia del procesado. Las primeras presentan grandes aglomerados de partículas de circona y mayor tamaño de grano de alúmina, mientras que el material fabricado a partir de precursores presenta una microestructura más homogénea. Se han realizado ensayos en compresión a temperaturas entre 1300 y 1450 °C, tensiones desde 20 a 600 MPa, y velocidad de deformación de 2 x 10'^ s'^, encontrando fractura frágil a T 1400 °C para ambos tipos de microestructura.Microstructure and high temperature compressive creep of tw^o ci cona toughened alumina (ZTA) ceramics, fabricated by pow^der processing and sol-gel precursors processing, has been studied, in order to determine the influence of processing. For the samples fabricated from powders, the microstructure is less homogeneous, with large agglomerates of circona, and greater alumina grain sizes. Compressive tests at temperatures between 1300 °C and 1400 °C, stresses between 20 and 600 MPa, at an strain rate of 2 x 10"^ s"^ have been carried out. Brittle fracture behavior was found for both materials below 1400 °C, and stationary plastic deformation above this temperature

Report on the Second Workshop on Distributed AI

On June 24, 1981 twenty-five participants from organizations around the country gathered in MIT's Endicott House for the Second Annual Workshop on Distributed AI. The three-day workshop was designed as an informal meeting, centered mainly around brief research reports presented by each group, along with an invited talk. In keeping with the spirit of the meeting, this report was prepared as a distributed document, with each speaker contributing a summary of his remarks.MIT Artificial Intelligence Laborator