On the gauge of the natural lineshape

We use a general formulation of nonrelativistic quantum electrodynamics in which the gauge freedom is carried by the arbitrary transverse component of the the Green's function for the divergence operator to calculate the natural lineshape of spontaneous emission, thus discerning the full dependence of the result on the choice of gauge. We also use a representation of the Hamiltonian in which the virtual field associated with the atomic ground state is explicitly absent. We consider two processes by which the atom is excited; the first is resonant absorption of incident radiation with a sharp line. This treatment is then adapted to derive a resonance fluorescence rate associated with the Lamb line in atomic hydrogen. Second we consider the atom's excitation due to irradiation with a laser pulse treated semi-classically. An experiment could be used to reveal which of the calculated lineshape distributions is closest to the measured one. This would provide an answer to a question of fundamental importance; how does one best describe atom-radiation interactions with the canonical formalism?Comment: 17 pages, 2 figures, 3 table

Modelling the backwash process in micro filtration

Microfiltration separates fine solids from a liquid substrate, but requires a process to remove the accumulated solids from the filtering device. In this study, a backwash process was examined, in which a flow of high-pressure air in the direction opposite to the usual fluid flow, is used to dislodge and remove the particles. The dynamics of the original air penetration of the filtering fibres, the flux balances of the displaced liquid, and the distribution of pressures through a network of modules were all studied. They fall naturally into a classification by increasing spatial scales

American Progressives and the European Left

Until comparatively recently, historians treated progressivism of the early twentieth century variety as if it were a purely American affair. In 1952, Eric F. Goldman argued that progressivism was ‘as exclusively national a movement as the United States ever knew’. But in the years that followed, a number of works appeared which challenged the validity of this narrowly national interpretation. Arthur Mann, in 1956, suggested that American reformers were much influenced by British social thought. Gertrude Almy Slichter drew attention to the European background of American reform in a 1960 dissertation. A number of essays then showed that progressivism itself could be regarded as part of an international movement. Peter F. Clarke pointed out that there had been a progressive movement in England which, in fact, predated the American equivalent. Kenneth O. Morgan, reviewing the nature of the links between British and American reformers, thought it meaningful to write in terms of ‘ Anglo-American Progressivism’. Other historians, looking at the matter in a more general, European context, were struck by the apparent similarities between American progressives, British Liberals or Labourites, and French and German socialists. George E. Mowry argued that American progressives should be regarded as part of western ‘social democracy’. Arthur A. Ekirch came to much the same conclusion

Volcanic studies by members of the Royal Society of London 1665 - 1780

Late seventeenth century ideas about volcanic activity were largely derived from classical sources. The Philosophical Transactions of the Royal Society of London provided a vehicle for publication of information about volcanoes where many ancient notions were refuted and new hypotheses suggested. Volcanic studies by members included detailed field reports, eyewitness accounts of eruptions as well as expeditions to extinct or dormant volcanic peaks, experiments with volcanic rocks, and speculation on the nature of subterranean "fires" and causes of eruptions. The development of theories concerning the formation of the columnar basalts of the Giant's Causeway is also traced. By the 1770's there appeared a general acceptance among members of the Royal Society of the igneous origin of basalt, the existence of ancient extinct volcanoes and the implications of past geologic change

Irreducibility of configurations

In a paper from 1886, Martinetti enumerated small $v_3$-configurations. One of his tools was a construction that permits to produce a $(v+1)_3$-configuration from a $v_3$-configuration. He called configurations that were not constructible in this way irreducible configurations. According to his definition, the irreducible configurations are Pappus' configuration and four infinite families of configurations. In 2005, Boben defined a simpler and more general definition of irreducibility, for which only two $v_3$-configurations, the Fano plane and Pappus' configuration, remained irreducible. The present article gives a generalization of Boben's reduction for both balanced and unbalanced $(v_r,b_k)$-configurations, and proves several general results on augmentability and reducibility. Motivation for this work is found, for example, in the counting and enumeration of configurations

Memory, Imagery, and Self-Knowledge

One distinct interest in self-knowledge concerns whether one can know about one’s own mental states and processes, how much, and by what methods. One broad distinction is between accounts that centrally claim that we look inward for self-knowledge (introspective methods) and those that claim that we look outward for self-knowledge (transparency methods). It is here argued that neither method is sufficient, and that we see this as soon as we move beyond questions about knowledge of one’s beliefs, focusing instead on how one distinguishes, for oneself, one’s veridical visual memories from mere (non-veridical) visual images. Given robust psychological and phenomenal similarities between episodic memories and mere imagery, the following is a genuine question that one might pose to oneself: “Do I actually remember that happening, or am I just imagining it?” After critical analysis of the transparency method (advocated by Byrne 2010, following Evans 1982) to this latter epistemological question, a brief sketch is offered of a more holistic and inferential method for acquisition of broader self-knowledge (broadly following the interpretive-sensory access account of Carruthers 2011). In a slogan, knowing more of the mind requires using more of the mind

Fifteenth century earth science

The earth science content of two late medieval encyclopedias, the Mirrour of the World and Higden's Polychronicon, both printed by William Caxton in the 1480's, is examined in relation to fifteenth century ideas about the physical nature of the earth and the universe. Such topics as the four elements, the earth and the spheres, location of Hell and Paradise, the arrangement of , continents and oceans, the unity of waters, earthquakes and volcanoes, erosion, fossils and mountain building, climatic zones and weather phenomena are summarized and reference made to the Biblical and Classical Greek sources of these ideas

Perceptions and determinants of healthy eating in high performing male adolescent rugby players : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand

Background: Rugby is a competitive sport in New Zealand, with the leading team, the All Blacks, ranked first in the world. Since nutrition plays an important role in sports performance, understanding how to facilitate young high-performing rugby players to eat healthy will help to optimise their performance. Research is lacking regarding perceptions and determinants of healthy eating for young rugby players, both in New Zealand and internationally. This study aimed to explore perceptions and determinants of healthy eating for high performing male adolescent rugby players living in New Zealand. Methods: Perceptions and determinants were explored using semi-structural individual interviews. Participants were 20 male high-performing rugby players aged 16 to 18 years. Interviews were recorded and transcribed for thematic analysis of themes. Results: Perceptions of healthy eating included balance and variety, portions according to energy needs and specific foods. Numerous determinants of healthy eating were described including factors related to the general lifestyle of an adolescent, including peers, family and food availability, cost, convenience and taste of food. Sports-specific determinants relating to participants’ athletic lifestyles were sports performance, motivation to perform, team culture and the timing, amount and types of food on the gastrointestinal tract. Some determinants were both general and sports-specific including the media, physical appearance and feeling good. Conclusion: High-performing male adolescent rugby players living in New Zealand have a good general understanding of the meaning of a healthy diet. A range of determinants influence the diet of these young rugby players, including general and sports-specific determinants from the macro-level, social and physical environment, as well as individual factors. Further research is required to explore the determinants of healthy eating in high-performing male adolescent rugby players both in New Zealand and internationally