On-demand Evaluation for Maude

Strategy annotations provide a simple mechanism for introducing some laziness in the evaluation of expressions. As an eager programming language, Maude can take advantage of them and, in fact, they are part of the language. Maude strategy annotations are lists of non-negative integers associated to function symbols which specify the ordering in which the arguments are (eventually) evaluated in function calls. A positive index enables the evaluation of an argument whereas 'zero' means that the function call has to be attempted. The use of negative indices has been proposed to express evaluation on-demand, where the demand is an attempt to match an argument term with the left-hand side of a rewrite rule. In this paper we show how to furnish Maude with the ability of dealing with on-demand strategy annotations.     

Flow regulation by dams affecting ichthyoplankton: the case of the Porto Primavera Dam,Paraná River,Brazil

The effects of a dam closure (Porto Primavera Dam) on reproduction of the main species that use the floodplain located below a nursery area were determined. Specifically, we examined, before and after the closure of the dam, the spatial distribution of larvae and the differences in density according to life strategy (migratory and non‐migratory species). Fifteen points distributed along the channels of the Paraná, Ivinheima and Paranapanema rivers were sampled, between 1997 and 2001, (October 1997 to December 1998—pre; and between January 1999 to March 2001—post closure), during the spawning period of most fish species found in the region (October to March). Samplings were always conducted at night, using a conical‐cylindrical plankton net (0.5 mm mesh) with a flowmeter attached. There were significant differences in larvae densities between pre and post dam closure for several species. Also, there were significant differences between the pre and post‐closure periods for densities of migratory and non‐migratory species, and between sampling sites. These findings indicate decline in densities and number of taxa caught after the closure of the dam. Larvae of migratory species, formerly common in the entire study area, were registered only in points influenced by the non dammed rivers (such as the Ivinheima River), indicating that the closure of Porto Primavera caused negative impacts on fish reproduction downstream of the dam. Copyright © 2006 John Wiley & Sons, Ltd.     

Signature analysis for fault detection of mixed-signal ICs based on dynamic power-supply current

In this paper we have investigated a unified and simultaneous fault detection method for mixed-signal integrated circuits. The method is based on the analysis of the power-supply current through the circuit under test. The analysis has been done paying attention to the dynamic behaviour of the power-supply current, in order to avoid measurement problems related to the large amount of quiescent current drop across many analog blocks.The analysis of the dynamic power-supply current entails certain problems related to the complexity of the measurement process, especially those due to the high speed of the current transients. These problems have been addressed by considering a design for test procedure based on the use of built-in dynamic current sensors.The goal of the design for test methodology proposed is to represent the Iddt through the mixed-signal IC under test by a digital signature. The paper presents some advantages of this approach such as a good tolerance to cross-talk noise and the need for only a conventional digital tester on the complete mixed-signal IC for fault detection. The analysis is illustrated with some test results.     

Parameter selection in the design of displacement and motion functions by means of B-splines

Journal of Mechanical Science and Technology - This work analyses the incidence of the parameter selection of B-spline curves, used in the design of displacement and motion functions, on its degree...     

Highly Efficient Coaxial TiO2‐PtPd Tubular Nanomachines for Photocatalytic Water Purification with Multiple Locomotion Strategies

Titania is a promising photocatalyst for water purification or production of solar fuels. However, due to its large band gap, titania is photoactive solely under UV light, which accounts for less than 5% of the solar spectrum. In this work, TiO₂‐based hybrid 1D nanostructures with photocatalytic activities extended to visible light region are designed and fabricated. Highly efficient coaxial TiO₂‐PtPd‐Ni nanotubes (NTs) are fabricated by a template‐assisted electrochemical synthesis route for water remediation under UV light, visible light, and natural sunlight. These coaxial hybrid nanotubes display a 100% degradation of organic pollutant rhodamine B in only 50 min (k‐value 0.071 min^?1) and 30 min under visible light and natural sunlight, respectively. For comparison, TiO₂ nanotubes doped with Pd nanoparticles are also fabricated and they show inferior photocatalytic properties and degrading stability over time. The multicomponent design enables to actuate the hybrid NTs by using two different external energy sources, i.e., magnetic and acoustic fields. Self‐propelled, autonomous actuation in the presence of H₂O₂ is also realized. These versatile actuation modes have the potential to enable the reported photocatalytic nanomachines to work efficiently under complex environments and to be easily collected for reuse.     

Hydrothermal Degradation Behavior of Y‐TZP Ceramics Sintered by Nonconventional Microwave Technology

Different factors such as the characteristics of starting powders, their processing, the sintering technique and the final sintering temperature were assessed with the goal to improve the low‐temperature degradation (LTD) resistance of 3Y‐TZP materials without compromising on the mechanical properties. The degradation of hydrothermally treated specimens was studied by AFM, nanoindentation technique, micro‐Raman spectroscopy, and electron microscopy. 3Y‐TZP previously prepared in laboratory by colloidal processing, and sintered by microwave method at low temperature (1200°C) led to excellent mechanical and LTD resistance, as compared to dental restorations based on Y‐TZP commercial material. In the former, the presence of m‐phase was almost nonexistent even after 200 h of exposure to LTD conditions and the initial mechanical properties were maintained, giving 16 and 250 GPa mean values for hardness and Young's modulus, respectively. The influence of the fast‐technology by microwave heating is presented with a nonconventional sintering method to fabricate 3Y‐TZP ceramics for dental application with very high resistance against LTD and optimized mechanical properties.     

Recognition by familiarity is preserved in Parkinson's without dementia and Lewy-Body disease.

Objective: The retrieval deficit hypothesis states that the lack of deficit in recognition often observed in patients with Parkinson's disease is because of the low retrieval requirements of the task, given that these patients have retrieval and not encoding deficits. To test this hypothesis we investigated recognition memory by familiarity in Parkinson's patients and in patients with Lewy Bodies disease and Parkinson with dementia. Method: We analyzed to what extent the experimental groups were able to recognize by familiarity in a typical yes/no recognition memory task. The experimental groups were patients with early nondemented Parkinson's disease, advanced nondemented Parkinson's disease, demented Parkinson's patients, and patients with dementia with Lewy Bodies. We compared their performance with a group of young and another group of old healthy participants. The estimation of familiarity was made by analyzing recognition of word targets and distractors consisting of combinations of different letters in comparison with a condition in which targets and distractors were composed of similar letters, even though subjects were unaware of the independent variable. Results: The results indicate that familiarity was used at the same level by controls, patients with early Parkinson's disease and patients with dementia with Lewy Bodies. Although late Parkinson patients also used familiarity, its effect was only marginally significant. Patients with Parkinson's disease and dementia were not capable of using familiarity in recognition memory. Conclusions: Our results support the retrieval deficit hypothesis as Parkinson's patients without dementia show no deficit in a situation in which the retrieval requirements are minimal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)