Short period eclipsing binary candidates identified using SuperWASP

We present light curves and periods of 53 candidates for short period eclipsing binary stars identified by SuperWASP. These include 48 newly identified objects with periods <2 × 10^4 s (~0.23 d), as well as the shortest period binary known with main sequence components (GSC2314–0530 = 1SWASP J022050.85 + 332047.6) and four other previously known W UMa stars (although the previously reported periods for two of these four are shown to be incorrect). The period distribution of main sequence contact binaries shows a sharp cut-off at a lower limit of around 0.22 d, but until now, very few systems were known close to this limit. These new candidates will therefore be important for understanding the evolution of low mass stars and to allow investigation of the cause of the period cut-off

On invariant sets in Lagrangian graphs

In this exposition, we show that a Hamiltonian is always constant on a compact invariant connected subset which lies in a Lagrangian graph provided that the Hamiltonian and the graph are smooth enough. We also provide some counterexamples for the case that the Hamiltonians are not smooth enough.Comment: 4 page

Library project management in a collaborative web-based working environment

This paper discusses the emerging paradigm of project management performed in a web-based working environment. It highlights how project management and its associated features are strongly linked to fulfilling quality and value criteria for customers, and it examines how collaborative working environments can greatly reduce the administrative burden of managing large projects, especially and almost paradoxically, when resources are limited. Specifically, the paper examines the application of a project management methodology (PRINCE2) together with the use of a collaborative web-based working environment over a number of pilot projects at Leeds University Library. It describes the pilot phase of a library management decision to run a series of major Library projects using project management methodology, while continuing to run other projects through the existing locally developed planning mechanisms and describes the pitfalls of these latter alternatives, less sophisticated project management tools, and describes the main issues that this change in practice has brought to light. It draws preliminary conclusions about the effectiveness of this change in practice in one of the UK’s largest academic libraries

Recovering Solar Toroidal Field Dynamics From Sunspot Location Patterns

We analyze both Kitt Peak magnetogram data and MDI continuum intensity sunspot data to search for the following solar toroidal band properties: width in latitude and the existence of a tipping instability (longitudinal m=1 mode) for any time during the solar cycle. To determine the extent which we can recover the toroidal field dynamics, we forward model artificially generated sunspot distributions from subsurface toroidal fields we assigned certain properties. We analyzed two sunspot distribution parameters using MDI and model data: the average latitudinal separation of sunspot pairs as a function of longitudinal separation, and the number of sunspot pairs creating a given angle with respect to the E-W direction. A toroidal band of 10 degrees width with a constant tipping of 5 degrees best fits MDI data early in the solar cycle. A toroidal band of 20 degrees width with a tipping amplitude decreasing in time from 5 to 0 degrees best fits MDI data late in the solar cycle. Model data generated by untipped toroidal bands cannot fit MDI high latitude data and can fit only one parameter at low latitudes. Tipped toroidal bands satisfy chi squared criteria at both high and low latitudes. We conclude this is evidence to reject the null hypothesis - that toroidal bands in the solar tachocline do not experience a tipping instability - in favor of the hypothesis that the toroidal band experiences an m=1 tipping instability. Our finding that the band widens from ~10 degrees early in the solar cycle to ~20 degrees late in the solar cycle may be explained in theory by magnetic drag spreading the toroidal band due to altered flow along the tipped field lines.Comment: This paper is accepted to Astrophysical Journal, September 2005 issu

Principles of Discrete Time Mechanics: IV. The Dirac Equation, Particles and Oscillons

We apply the principles of discrete time mechanics discussed in earlier papers to the first and second quantised Dirac equation. We use the Schwinger action principle to find the anticommutation relations of the Dirac field and of the particle creation operators in the theory. We find new solutions to the discrete time Dirac equation, referred to as oscillons on account of their extraordinary behaviour. Their principal characteristic is that they oscillate with a period twice that of the fundamental time interval T of our theory. Although these solutions can be associated with definite charge, linear momentum and spin, such objects should not be observable as particles in the continuous time limit. We find that for non-zero T they correspond to states with negative squared norm in Hilbert space. However they are an integral part of the discrete time Dirac field and should play a role in particle interactions analogous to the role of longitudinal photons in conventional quantum electrodynamics.Comment: 27 pages LateX; published versio

Development and evaluation of an intervention to improve further education students' understanding of higher education assessment criteria: three studies

Three studies about helping Further Education students prepare for study at universityThis paper reports three studies about preparing Further Education (FE) students for the transition to Higher Education (HE) by improving their understanding of HE assessment criteria. In study 1, students and tutors in both FE and HE were interviewed for a qualitative analysis of their understandings and expectations about assessment criteria. In study 2, students in FE and HE completed questionnaires measuring self-rated understanding and ability about assessment criteria, and beliefs about essay writing. Studies 1 and 2 both showed that FE students were more confident than HE students about their understanding and ability in relation to assessment criteria, but FE students’ understandings suggested more surface approaches to learning and more naïve epistemological beliefs. In study 3, a workshop intervention to improve FE students’ understandings of HE assessment criteria was evaluated in a comparative longitudinal trial. The intervention reduced FE students’ self-rated understanding and ability, and promoted more sophisticated beliefs about essay writing, by comparison with students who received standard tuition. We concluded that interventions to develop more realistic understandings of what is required in academic writing could be used to prepare FE students more effectively for the transition to HE

Herbal medicines in Hawaii from tradition to convention.

The stories of kava and chaulmoogra demonstrate the importance of herbal products in ancient and recent Hawaiian medicine. Kava is a psychoactive beverage that has been used ceremonially for millennia throughout the Pacific. It is a nonfermented depressant that causes tranquil intoxication in which thoughts and memory remain clear. Its broad pharmacologic activity led to use in Hawaii to treat skin disorders and later in Germany to treat gonorrhea. Kava is now available outside the Pacific basin as a relaxant, emerging as a popular, albeit deritualized, natural product. In the late 19th century, the main treatment for leprosy was chaulmoogra, extracted from Hydnocarpus seeds. Chaulmoogra had been a traditional treatment for skin diseases in Ayurvedic and Chinese medicine. Chaulmoogra from Asian markets was expensive and usually adulterated so the USDA decided to plant Hydnocarpus in Hawaii. Joseph Rock, a botanist at University of Hawaii, trekked through southeast Asia collecting fresh seeds to plant on Oahu. Rock's trees provided chaulmoogra for leprosy patients on Molokai and elsewhere until it was replaced by dapsone. Chaulmoogra, once the treatment for leprosy worldwide, is now nearly forgotten; kava, once poorly known outside the Pacific, is now a widely-used alternative medicine. Hawaii will probably continue its role in the transition of plants from traditional use to conventional use