Self-Avoiding Gonihedric Srting and Spin Systems

We classify different theories of self-intersecting random surfaces assigning special weights to intersections. When self-intersection coupling constant $\kappa$ tends to zero, then the surface can freely inetrsect and it is completely self-avoiding when $\kappa$ tends to infinity. Equivalent spin systems for this general case were constructed. In two-dimension the system with $\kappa = 0$ is in complete disorder as it is in the case of 2D gauge Ising system.Comment: Preprint CRETE-TH-21, October 1993,8 pages,Late

An Observational Overview of Solar Flares

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections. We also discuss flare soft X-ray spectroscopy and the energetics of the process. The emphasis is to describe the observations from multiple points of view, while bearing in mind the models that link them to each other and to theory. The present theoretical and observational understanding of solar flares is far from complete, so we conclude with a brief discussion of models, and a list of missing but important observations.Comment: This is an article for a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

The control of airway function and the assessment of airway calibre

Airway calibre is determined by age and genetic factors and can be modulated by the parasympathetic nervous system, sympathetic activity, and the non-adrenergic, non-cholinergic system. Worldwide, the most important diseases causing airway obstruction are chronic obstructive pulmonary disease (COPD) and asthma. Although both diseases are caused by chronic airway inflammation, their underlying pathophysiological mechanisms are different. COPD is characterised by a persistent, progressive airflow limitation that is barely reversible. In asthma, airflow limitation is often variable and episodic. Although airflow limitation may be absent in clinically active patients, bronchial hyper-responsiveness is almost invariably present. Spirometry is commonly used to diagnose airway obstruction. Reversibility of airway obstruction may be assessed in patients with this disorder, but does not always allow the clinician to differentiate asthma and COPD. In patients without airway obstruction, measurements of bronchial hyper-responsiveness with indirect or direct challenges should be performed. A negative challenge test rules out the diagnosis of asthma with reasonable certainty