Теоретичне прогнозування критичних станів вертикальних колон надглибинного буріння

Поставлена задача об устойчивости и свободных колебаниях глубоких вращающихся бурильных колонн, которые преднапряжены продольной силой и крутящим моментом. С учетом статических и динамических эффектов силового взаимодействия указанных механических факторов построены разрешающие уравнения. Предложена методика их решения, основанная на применении метода продолжения по параметру и метода ортогонализации. Выполнены исследования устойчивости и колебаний бурильных колонн длиной до 10000 мThe problem about free vibrations of rotating drill columns prestressed by torque and longitudinal force is stated. The constitutive equations are formulated with allowance made for static and dynamic effects of force interaction betwen the mentioned factors. The techniques of the equation integration are proposed, wich are based on application of the transfer matrix method and the orthogonalization method. The investigations of stability and vibrations of the 10 km length drill strings are performed

Hierarchy of Scales in Language Dynamics

Methods and insights from statistical physics are finding an increasing variety of applications where one seeks to understand the emergent properties of a complex interacting system. One such area concerns the dynamics of language at a variety of levels of description, from the behaviour of individual agents learning simple artificial languages from each other, up to changes in the structure of languages shared by large groups of speakers over historical timescales. In this Colloquium, we survey a hierarchy of scales at which language and linguistic behaviour can be described, along with the main progress in understanding that has been made at each of them − much of which has come from the statistical physics community. We argue that future developments may arise by linking the different levels of the hierarchy together in a more coherent fashion, in particular where this allows more effective use of rich empirical data sets

Estimation and utilization of inbreeding and dominaxce genetic Effects in genetic evaluation of purebred american swine

Genetic evaluation in swine is currently conducted utilizing additive genetic models. Historical studies have examined the relative influence of inbreeding on phenotypic performance; however, until recently estimation of dominance genetic effects fi-om large populations have proven prohibitive. Utilizing Method R, single-trait estimation of inbreeding and dominance genetic effects were conducted for a population of purebred American Yorkshire swine. The traits analyzed included number born alive (NBA), 21.day litter weight (LWT), days to 104.5 kg (DAYS), and backfat at 104.5 kg (BF). Dominance and inbreeding were found to have sizeable influence for the reproductive and growth traits analyzed. Subsequent analysis analyzed the changes in prediction of additive breeding values when including inbreeding or dominance and inbreeding effects in the genetic prediction model. Inbreeding had greatest influence on prediction of additive breeding value for inbred individuals or families. On average, inclusion of dominance genetic effects seemed to influence smaller changes

Mycobacterium interface keratitis after laser in situ keratomileusis

To report the clinical course, management, and outcome of infectious interface keratitis caused by mycobacterium species after laser in situ keratomileusis (LASIK). A small noncomparative interventional case series. Five eyes in four patients who underwent LASIK in different locations around the world and had culture-positive mycobacterium keratitis develop. The LASIK flap was lifted or amputated, samples were submitted for Ziehl-Neelsen acid-fast stain and Lowenstein-Jensen’s agar cultures for diagnosis; topical treatment with fortified clarithromycin and amikacin was administered until clinical resolution. Time periods from onset to diagnosis and from diagnosis to clinical resolution, and the final visual acuity. Onset of symptoms of infection occurred after a mean of 20 days (range, 11 days–6 weeks) after LASIK or an enhancement procedure. Definitive diagnosis was obtained after a mean period of 4.5 weeks (range, 12 days–8 weeks) from onset. Keratitis resolved within 8.4 weeks (range, 1–18 weeks) of treatment with fortified clarithromycin and amikacin. Corticosteroids were found to worsen and prolong the course of disease. In four of five eyes the LASIK flap was amputated. Mycobacterial keratitis is a potentially vision-threatening complication after LASIK, characterized by a long latent period, delayed diagnosis, and a protracted course even under intensive specific antibiotic therapy. Inclusion of specific culture media and staining protocols for mycobacteria, along with aggressive treatment on diagnosis, including lifting or amputating the LASIK flap, culturing, topical fortified clarithromycin and amikacin, while avoiding corticosteroids, may significantly improve resolution of the infection and potentially improve the visual outcome

Effective Treatment of Phlyctenular Keratoconjunctivitis with Oral Tetracycline

Purpose: To determine the clinical characteristics, possible etiologic agents, and response to oral antibiotic therapy in patients with phlyctenular keratoconjunctivitis. Methods: The authors reviewed the medical records of the 17 patients with phlyctenular keratoconjunctivitis who were seen and treated at the Bascom Palmer Eye Institute between 1981 and 1991. Results: All 17 patients were younger than 18 years of age at the onset of their disease. Girls (n =14) outnumbered boys (n = 3) 4:1. Significant incapacitating symptoms and ocular morbidity occurred frequently, including three perforated corneas. Five of ten patients who were tested for Chlamydia infection had positive test results and five patients possibly had early rosacea dermatitis. All patients experienced long-term remission of their ocular disease after a course of oral tetracycline or erythromycin. Two patients demonstrated unique linear (fascicular) corneal phlyctenules. Conclusion: Oral tetracycline or erythromycin treatment produces long-lasting remission of phlyctenular keratoconjunctivitis in affected children