On the attractors of two-dimensional Rayleigh oscillators including noise

We study sustained oscillations in two-dimensional oscillator systems driven by Rayleigh-type negative friction. In particular we investigate the influence of mismatch of the two frequencies. Further we study the influence of external noise and nonlinearity of the conservative forces. Our consideration is restricted to the case that the driving is rather weak and that the forces show only weak deviations from radial symmetry. For this case we provide results for the attractors and the bifurcations of the system. We show that for rational relations of the frequencies the system develops several rotational excitations with right/left symmetry, corresponding to limit cycles in the four-dimensional phase space. The corresponding noisy distributions have the form of hoops or tires in the four-dimensional space. For irrational frequency relations, as well as for increasing strength of driving or noise the periodic excitations are replaced by chaotic oscillations.Comment: 9 pages, 5 figure

Stability of adhesion clusters under constant force

We solve the stochastic equations for a cluster of parallel bonds with shared constant loading, rebinding and the completely dissociated state as an absorbing boundary. In the small force regime, cluster lifetime grows only logarithmically with bond number for weak rebinding, but exponentially for strong rebinding. Therefore rebinding is essential to ensure physiological lifetimes. The number of bonds decays exponentially with time for most cases, but in the intermediate force regime, a small increase in loading can lead to much faster decay. This effect might be used by cell-matrix adhesions to induce signaling events through cytoskeletal loading.Comment: Revtex, 4 pages, 4 Postscript files include

The Photon Structure Function at Small-x

It is shown that recent small-x measurements of the photon structure function F_2^{\gamma}(x,Q^2) by the LEP-OPAL collaboration are consistent with parameter-free QCD predictions at all presently accessible values of Q^2.Comment: 7 pages, LaTeX, 2 figure

Conceptual change challenges in medicine during professional development

This study investigates professional development during medical studies from a conceptual change perspective. Medical students' conceptual understanding and clinical reasoning concerning the central cardiovascular system were investigated during the first three years of study. Professional development was inspected from the perspectives of biomedical knowledge, clinical knowledge and skills needed to solve a patient case. Biomedical misconceptions regarding false beliefs and mental models were detected. Students with misconceptions were more likely to give lower level answers in clinical application tasks and to make inaccurate diagnoses compared to those students who had accurate conceptual understanding. Based on the results, pedagogical suggestions are discussed

Influence heat-reflective coating on the decrease of heat losses of window constructions

Developed theoretical and methodological foundations of the optimal choice of space-planning and constructive decisions of low-rise buildings blocked type, aimed at improving efficiency of investment, energy and resource saving, creation of comfortable conditions for the population, ensure sustainable development of low-rise construction in the context of socio-economic priorities in the climatic zoning of the area of construction

GERENCIAMENTO DO CUIDADO EM ENFERMAGEM: QUESTIONANDO ESTRATÉGIAS

O gerenciamento em enfermagem é uma das mais significativas áreas de abrangência da enfermagem. Suas estratégias no provimento do cuidado no contexto hospitalar são desveladas neste estudo exploratório. O enfermeiro gerente se mostra como um exímio controlador do sistema de cuidados de enfermagem, detentor do poder e da autoridade, e com poucos momentos de participação da equipe. Apresenta-se os resultados das entrevistas agrupadas em o que é gerenciamento, organização do processo de cuidado, estratégias de gerenciamento, relação grupo de trabalho e gerente, são diferenças entre turnos e dias da semana. Há necessidade preemente de pensar e repensar as estratégias de gerenciamento do cuidado gerente as atitudes, papéis ou práticas orientadas pelos atuais fundamentos teóricofilosóficos do gerenciamento em administração.Nursing care management is one of the most significant areas within the scope of nursing profession. In this exploratory study, strategies for providing care in a hospital setting are unveiled. The nurse managers show themselves as controlers of the nursing care system, holding power and authority, and having few moments of team members participation in the decision making process. The results of the interviews are grouped in the following categories: what is management, organization of the caring process, management, strategies, team work and manager relationships, differences in shifts and days of the week. There is an urgent need to re-think strategies for nursing care management in regards to attitudes, roles and practices based on theorical - philosophical aspects of management in administration