The relationship between andragogical and pedagogical orientation and the implications for adult learning

Current literature suggests that the relationship between andragogy and pedagogy is based on a continuum. This study found that the relationship of andragogical and pedagogical orientations, measured by the Students' Orientation Questionnaire, is more correctly represented as being orthogonal or at right angles to each other. Such an orthogonal relationship reflects the complexities involved in adult learning. This paper discusses the implications for both the learning process and for future research

Galactic positrons and electrons from astrophysical sources and dark matter

A very interesting puzzle about the origin of electron and positron cosmic rays is deduced from the latests experimental results. We model the propagation of such cosmic rays in terms of a successfully tested two--zone propagation model. Several theoretical uncertainties -- like ones related to propagation -- are considered to study different types of electron and positron sources: dark matter annihilation, secondary production, and supernova remnants.Comment: 3 pages, 1 figure. Proceedings for conference "Topics in Astroparticle and Underground Physics" (TAUP2009). Rome, July 1-5, 200

A Graphical Language for Proof Strategies

Complex automated proof strategies are often difficult to extract, visualise, modify, and debug. Traditional tactic languages, often based on stack-based goal propagation, make it easy to write proofs that obscure the flow of goals between tactics and are fragile to minor changes in input, proof structure or changes to tactics themselves. Here, we address this by introducing a graphical language called PSGraph for writing proof strategies. Strategies are constructed visually by "wiring together" collections of tactics and evaluated by propagating goal nodes through the diagram via graph rewriting. Tactic nodes can have many output wires, and use a filtering procedure based on goal-types (predicates describing the features of a goal) to decide where best to send newly-generated sub-goals. In addition to making the flow of goal information explicit, the graphical language can fulfil the role of many tacticals using visual idioms like branching, merging, and feedback loops. We argue that this language enables development of more robust proof strategies and provide several examples, along with a prototype implementation in Isabelle

Observation of thermally activated glassiness and memory dip in a-NbSi insulating thin films

We present electrical conductance measurements on amorphous NbSi insulating thin films. These films display out-of equilibrium electronic features that are markedly different from what has been reported so far in disordered insulators. Like in the most studied systems (indium oxide and granular Al films), a slow relaxation of the conductance is observed after a quench to liquid helium temperature which gives rise to the growth of a memory dip in MOSFET devices. But unlike in these systems, this memory dip and the related conductance relaxations are still visible up to room temperature, with clear signatures of a temperature dependent dynamics

A new species of Physopleurus Lacordaire from French Guiana (Coleoptera, Cerambycidae, Prioninae)

Misidentified as Physopleurus crassidens (Bates, 1869) since the beginning of the 20th century by some authors, a new species from French Guiana is herein described: Physopleurus ubirajarai sp. nov

OPserver: interactive online-computations of opacities and radiative accelerations

Codes to compute mean opacities and radiative accelerations for arbitrary chemical mixtures using the Opacity Project recently revised data have been restructured in a client--server architecture and transcribed as a subroutine library. This implementation increases efficiency in stellar modelling where element stratification due to diffusion processes is depth dependent, and thus requires repeated fast opacity reestimates. Three user modes are provided to fit different computing environments, namely a web browser, a local workstation and a distributed grid.Comment: 5 pages, 1 figur

A Proof Strategy Language and Proof Script Generation for Isabelle/HOL

We introduce a language, PSL, designed to capture high level proof strategies in Isabelle/HOL. Given a strategy and a proof obligation, PSL's runtime system generates and combines various tactics to explore a large search space with low memory usage. Upon success, PSL generates an efficient proof script, which bypasses a large part of the proof search. We also present PSL's monadic interpreter to show that the underlying idea of PSL is transferable to other ITPs.Comment: This paper has been submitted to CADE2

Transport and cooling of singly-charged noble gas ion beams

The transport and cooling of noble gas singly-charged ion beams by means of a Radio Frequency Quadrupole Cooler Buncher (RFQCB) have been studied at the LIMBE low energy beam line of the GANIL facility. Ions as light as $^{4}He^+$ have been cooled and stored before their extraction in bunches using $H_2$ as buffer gas. Bunches characteristics have been studied as a function of the parameters of the device. Sizeable transmissions of up to 10 $$ have been obtained. A detailed study of the lifetime of ions inside the buncher has been performed giving an estimate of the charge exchange cross-section. Results of a microscopic Monte-Carlo transport code show reasonable agreement with experimental data.Comment: 13 figure