Reply to the comment by Jacobs and Thorpe

Reply to a comment on "Infinite-Cluster geometry in central-force networks", PRL 78 (1997), 1480. A discussion about the order of the rigidity percolation transition.Comment: 1 page revTe

A wave-function Monte Carlo method for simulating conditional master equations

Wave-function Monte Carlo methods are an important tool for simulating quantum systems, but the standard method cannot be used to simulate decoherence in continuously measured systems. Here we present a new Monte Carlo method for such systems. This was used to perform the simulations of a continuously measured nano-resonator in [Phys. Rev. Lett. 102, 057208 (2009)].Comment: 4 pages, revtex 4, 1 eps figure. v2: correction to Eqs (3),(9), and (11); v3 added further informatio

Assessment of groundwater extraction in the Tadla irrigated perimeter (Morocco) using the SSEBI remote sensing algorithm

In the Tadla irrigation perimeter, farmers supplement their irrigation supplies with groundwater, leading to water table depletion in the area. An additional concern is the deteriorating water quality in the area. There is no regulation to control withdrawals of groundwater, and no data are available to quantify groundwater use. The paper demonstrates a method based on remote sensing techniques and field observation data to estimate the ground water use for the 2006 hydrological year. Calculations show that for Tadla, average groundwater use amounts to around 55% of the surface irrigation water use. This is substantial, and requires immediate attention. Policy recommendations are needed to control the use of groundwater and to reach an integral management with the canal water. For exact calculations, data on groundwater levels are needed

Free and open source software in computing education

Free and Open Source Software (FOSS) exemplifies the merit and successes of open content, understood broadly as creative work that explicitly allows sharing and further changes by anyone, whether an individual or organization. Although the benefits of improving computing education with open source practices are largely acknowledged, transforming teaching to create effective learning environments has many challenges. The panelists will bring different perspectives on teaching strategies and curricular content they have used in their classrooms. These perspectives will exemplify key issues with FOSS-based education and FOSS-based IT systems. The developer and user communities established around FOSS-based IT systems are of particular interest to the IT discipline because of its focus on user centeredness and advocacy for advancing professional practices in authentic environments

Instrument continuously measures density of flowing fluids

Electromechanical densitometer continuously measures the densities of either single-phase or two-phase flowing cryogenic fluids. Measurement is made on actual flow. The instrument operates on the principle that the mass of any vibrating system is a primary factor in determining the dynamic characteristics of the system

Fibrational induction rules for initial algebras

This paper provides an induction rule that can be used to prove properties of data structures whose types are inductive, i.e., are carriers of initial algebras of functors. Our results are semantic in nature and are inspired by Hermida and Jacobs’ elegant algebraic formulation of induction for polynomial data types. Our contribution is to derive, under slightly different assumptions, an induction rule that is generic over all inductive types, polynomial or not. Our induction rule is generic over the kinds of properties to be proved as well: like Hermida and Jacobs, we work in a general fibrational setting and so can accommodate very general notions of properties on inductive types rather than just those of particular syntactic forms. We establish the correctness of our generic induction rule by reducing induction to iteration. We show how our rule can be instantiated to give induction rules for the data types of rose trees, finite hereditary sets, and hyperfunctions. The former lies outside the scope of Hermida and Jacobs’ work because it is not polynomial; as far as we are aware, no induction rules have been known to exist for the latter two in a general fibrational framework. Our instantiation for hyperfunctions underscores the value of working in the general fibrational setting since this data type cannot be interpreted as a set