Approximate Selection Rule for Orbital Angular Momentum in Atomic Radiative Transitions

We demonstrate that radiative transitions with \Delta l = - 1 are strongly dominating for all values of n and l, except small region where l << n.Comment: 5 pages, 1 figur

Primary prevention of atherosclerosis and obesity in young adults using dietary and educational interventions

The purpose of the studies presented in this dissertation was to examine specific dietary and educational strategies to prevent atherosclerosis and obesity in young adults. The first study determined the effect of a single daily dose of soybean phytosterols added to ground beef on plasma total cholesterol total and LDL cholesterol concentrations in mildly hypercholesterolemic young men. In a 4-week study, 34 male college students were randomly assigned to the control (ground beef alone) or treatment (ground beef with 2.7 g of phytosterols) groups. Consumption of phytosterol-fortified ground beef lowered plasma total and LDL cholesterol by 9% and 15%, respectively, compared with the control group (p \u3c 0.001). The second study tested a hypothesis that a nutrition science course helps prevent weight gain during the first 16 months of college life. Forty female college freshmen were randomly assigned to the intervention (college course, n = 21) or control (no course, n = 19) groups. At the end of the course higher BMI (\u3e24) students in the intervention group (n = 11) consumed less fat (p = 0.04), protein (p = 0.03), and carbohydrate (p = 0.008) than did the higher BMI students in the control group (n = 6). Dietary changes reported by the higher BMI intervention students were associated with the maintenance of baseline body weight for one year in contrast with the higher BMI control students who gained 8.4 +/- 6.8 kg (p = 0.012). The third study examined college students\u27 concerns, attitudes, beliefs, and knowledge regarding body weight. A written questionnaire was administered to 220 undergraduate students. The results showed that 75% of students had a BMI \u3c25, yet 77% wanted to lose weight and 74% reported a history of weight loss attempts. Male and female students differed significantly in their perceived ability to control body weight and their reasons for weight concern. Students generally were aware of biologic and lifestyle factors influencing body weight and fatness but had limited understanding of the mechanisms by which these factors exert their effects

The failure criterion based on hydrogen distribution ahead of the fatigue crack tip

The hydrogen effect on the fracture toughness and fatigue crack growth behaviour in themartensitic high strength steel is investigated. The secondary ion mass spectrometry method has beenemployed to analyse the distribution of hydrogen concentration in the zone of the crack tip and at its edges.Changes in hydrogen concentration are observed in the vicinity of the propagating crack tip and at a remotesite. The hydrogen peak H C is reduced and moves away from the fatigue crack tip with the increase of themaximum stress intensity factor max K . The concept of damage evolution is used to explain fatigue crackpropagation in connection with the hydrogen redistribution ahead of the crack tip. The physical failure criterionbased on the hydrogen peak in the vicinity of the fatigue crack tip and the maximum stress intensity factor hasbeen proposed. The criterion reflects changes in the hydrogen peak which resulted from the hydrogenredistribution due to the increase of the maximum stress intensity factor as the crack length increases underfatigue loading

Fracture mechanics research at Mechanical Engineering Research Institute of the Russian Academy of Sciences

Conferencia invitada.Fracture Mechanics is currently an essential subject for understanding failure mechanisms of engineering materials and components. Accurate and rapid evaluation of singular and non-singular terms of stress, strain and displacement fields in the neighbouring of the tip of a fatigue crack is the foundation of multi-parameter Fracture Mechanics [1]. These terms are normally described by means of the Stress Intensity Factor (SIF) and the T stresses and are very useful to assess the level of safety [2] and the stability of cracks and crack-like defects in mechanical components prone to linear elastic failure, both under constant [2–7] and variable amplitude loading [8–11]. In general, evaluation of such terms cannot be performed only by finite element method [12–14]. This is due to the difficulty in accurately accounting for load level and exact geometry and orientation of defects [3,15]. Consequently, hybrid methods that incorporate experimental information [16,17] into an analytical and/or a numerical approach tend to be more trustworthy. Among these, full-field experimental techniques such as electronic speckle pattern interferometry [18–20], digital image correlation [21–27], thermo-elastic stress analysis [28–30], X-ray diffraction [31–33] and photo-elasticity [34–38] are often preferred. Estimation of Fracture Mechanics parameters requires accurate positioning of the crack tip. Moreover, local deformations as well as rigid body movements need to be taken into consideration. This research will summarise a general methodology including the above-described aspects for Fracture Mechanics analyses.Departamento de Ingeniería Civil, de Materiales y Fabricación Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Cutting'aesthetic teeth' : Flannery O'Connor's habit of art

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e ExpressãoEste trabalho foi sugerido pela afirmação de Flannery O'Connor que sua "dedicação estética" nasceu através do contato com Art and Scholasticism de Jacques Maritain. O propósito foi chegar a uma interpretação do sentido da frase. Uma investigação detalhada foi feita do conteúdo de Art and Scholasticism, posteriormente contrastada com os resultados de uma pesquisa feita em seus ensaios e suas cartas, o que revelou numerosos ecos de diversos trechos constando no texto de Maritain. Três pontos principais foram escolhidos como critérios na análise do hábito artístico de O'Connor: 1) a prática de arte implica uma luta; 2) a arte somente pode ser percebida pelos sentidos; e 3) a prática de arte exige do artista a dedicação indivisa à obra nascente. O estudo conclui que, para O'Connor, o brotar da dentição estética, através da leitura de Art and Scholasticism, significou que, ao perceber na análise da natureza da arte algo com que podia concordar, ela reconheceu tanto sua própria capacidade de tornar-se uma artista literária, quanto sua vontade de assumir a tarefa de desenvolver em sua pessoa o hábito de arte