Photometric support for future astonomical research

The I.A.P.P.P. is described and how that organization can provide photometric support for future astronomical research projects such as the 1982-1984 eclipse of epsilon Aurigae discussed at this workshop. I.A.P.P.P., International Amateur-Professional Photoelectric Photometry, is an organization founded in Fairborn, Ohio by the authors in 1980. Its purpose is to encourage contact between amateur and professional astronomers interested in photoelectric photometry, for their mutual benefit and for the benefit of astronomical research. Aspects dealt with include instrumentation, electronics, computer hardware and software, observing techniques, data reduction, and observing programs. Starting with the June 1980 issue, I.A.P.P.P. has published the quarterly I.A.P.P.P. Communications. The Communications contain articles dealing with all the above aspects of photoelectric photometry, although it does not publish observational results as such. Photoelectric photometry obtained by amateurs is published in the same journals which publish photometry obtained by professionals

Casimir torque between nanostructured plates

We investigate in detail the Casimir torque induced by quantum vacuum fluctuations between two nanostructured plates. Our calculations are based on the scattering approach and take into account the coupling between different modes induced by the shape of the surface which are neglected in any sort of proximity approximation or effective medium approach. We then present an experimental setup aiming at measuring this torque.Comment: 7 pages, 7 figure

Project management : learning by breaking the rules

The paper explores project management in action in a large public research organisation – NLAT which decided to change its internal organisation from team-based to project-based organisation a few years ago. A systematic and comparative analysis of 8 projects reveals that adherence to the ISO 9000’s standardized rules of project management - specific staffing and project leaders, definition of milestones ex ante, procedure manuals, and formalized learning accumulation mechanisms - had little to do with the organisations success over recent years: Looking for explanations for this success, the paper focuses on the process of transferring from one project to another, enhancing organisational learning through rules breaking. We identify three elements which encourage the accumulation of knowledge and competencies, as organisational learning: low project core staffing levels which stimulates the circulation of engineers and researchers between projects and blurs project boundaries, implementing and managing thematic projects which build on specific competencies developed in dedicated projects and encouraging ‘bricolage’ to hybridise project management with traditional hierarchical management practices.PROJECT MANAGEMENT;R&D;HIGH TECH;MANAGEMENT PRACTICES

Analysis of the absorption and emission spectra of U4+ in α-ThBr 4

The low temperature form α-ThBr4 has a scheelite structure I41/a in which the tetravalent uranium occupies the thorium site which is S4. Assuming that the ground state remains Γ 4 as in the β-ThBr4 form, the polarized absorption spectrum at 4.2 K shows that D2d is a good approximation. A peculiarity of this host is the exaltation of very numerous fluorescences of U4+ which permit to assign four Stark levels of the ground state 3H4 : Γ5 at 110 cm-1, Γ 1 at 473 cm-1, Γ1 at 623 cm-1 and Γ5 at 830 cm-1. 30 levels have been assigned and the crystal field parameters of U4+ (5f2) have been calculated in the D2d approximation : B20 = - 382, B40 = - 3 262, B44 = - 1734, B60 = - 851 and B64 = - 1828 cm-1. It is interesting to note that a small distortion in the scheelite structure of the α-ThBr4 compared with the zircon structure β-ThBr4 induces important changes in the crystal field parameters

The role of Surface Plasmon modes in the Casimir Effect

In this paper we study the role of surface plasmon modes in the Casimir effect. First we write the Casimir energy as a sum over the modes of a real cavity. We may identify two sorts of modes, two evanescent surface plasmon modes and propagative modes. As one of the surface plasmon modes becomes propagative for some choice of parameters we adopt an adiabatic mode definition where we follow this mode into the propagative sector and count it together with the surface plasmon contribution, calling this contribution "plasmonic". The remaining modes are propagative cavity modes, which we call "photonic". The Casimir energy contains two main contributions, one coming from the plasmonic, the other from the photonic modes. Surprisingly we find that the plasmonic contribution to the Casimir energy becomes repulsive for intermediate and large mirror separations. Alternatively, we discuss the common surface plasmon defintion, which includes only evanescent waves, where this effect is not found. We show that, in contrast to an intuitive expectation, for both definitions the Casimir energy is the sum of two very large contributions which nearly cancel each other. The contribution of surface plasmons to the Casimir energy plays a fundamental role not only at short but also at large distances.Comment: 10 pages, 3 figures. TQMFA200

Schur elements for the Ariki-Koike algebra and applications

We study the Schur elements associated to the simple modules of the Ariki-Koike algebra. We first give a cancellation-free formula for them so that their factors can be easily read and programmed. We then study direct applications of this result. We also complete the determination of the canonical basic sets for cyclotomic Hecke algebras of type $G(l,p,n)$ in characteristic 0.Comment: The paper contains the results of arXiv:1101.146

Casimir energy and geometry : beyond the Proximity Force Approximation

We review the relation between Casimir effect and geometry, emphasizing deviations from the commonly used Proximity Force Approximation (PFA). We use to this aim the scattering formalism which is nowadays the best tool available for accurate and reliable theory-experiment comparisons. We first recall the main lines of this formalism when the mirrors can be considered to obey specular reflection. We then discuss the more general case where non planar mirrors give rise to non-specular reflection with wavevectors and field polarisations mixed. The general formalism has already been fruitfully used for evaluating the effect of roughness on the Casimir force as well as the lateral Casimir force or Casimir torque appearing between corrugated surfaces. In this short review, we focus our attention on the case of the lateral force which should make possible in the future an experimental demonstration of the nontrivial (i.e. beyond PFA) interplay of geometry and Casimir effect.Comment: corrected typos, added references, QFEXT'07 special issue in J. Phys.

A Decade-Long Change in the Elevational Distribution of Non-Volant Small Mammals on Mount Meru, Tanzania

Understanding species distribution across elevational gradients is crucial for developing conservation strategies for montane biotic systems. A survey of small mammals was conducted on Mount Meru at six elevations, ranging between 1500 m and 3650 m. A total of 803 small mammal individuals, including 2 shrew species and 13 rodent species, were documented. Of these, Crocidura newmarki and Lophuromys verhageni were endemic on Mount Meru. Species richness was highest at mid-elevations, which is in line with the global pattern for small mammals. Prior to our study, the most complete data on small mammals on Mount Meru was collected in 2009. Our study provides an opportunity to show how small mammal elevational distribution has changed, over the last decade. We found six species (Arvicanthis niloticus, Mastomys natalensis, Lemniscomys striatus, Dasymys incomtus, Cricetomys ansorgei, and Montemys delectorum), which were not documented in 2009, but did not find Otomys tropicalis. Interestingly, the community composition at higher elevations in 2021 resembles that at lower elevations in 2009, suggesting that small mammal species have moved their range upward over time. Climate change could be a factor associated with the distributional shift found