Specification of internal accounting controls in a database environment

This paper examines the problem of specifying database security controls in a manner such that the resulting segmentation of data and the patterns of access rights are consistent with traditional accounting concepts that govern segregation of duties. The mechanism we use for implementation of these controls in a relational accounting system is that of a “view” implemented on the Query-by-Example database management system. A number of examples are presented in detail and some further aspects of security and integrity constraints are discussed.     

Effects of participant modeling on information acquisition and skill utilization.

Assessed the contribution of active participant modeling in coping skills training by evaluating 2 critical process variables: the retention of information about the threatening events and how to cope with them, and the visceral component of imaginal rehearsal. 38 8–13 yr old children, highly fearful of dentists (the Dental subscale of the Children's Fear Survey Schedule), were shown a videotape of 2 children practicing controlled respiration and imagery techniques while undergoing dental treatment. The participant modeling group was encouraged to practice these as they watched the film, whereas the symbolic modeling group was told that this might help them during their own dental treatment, which immediately followed videotape preparation. Ss who had the active participant instructions obtained more information from the videotape, reported greater reduction in dental anxiety, and showed lower respiratory rates as they watched the videotape. They reported greater use of imagery techniques and enhanced self-control. The degree of disruptiveness was significantly lower during subsequent actual dental treatment in Ss from the active practice group. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Amygdaloid lesion increases the toxicity of intrahippocampal kainic acid injection and reduces the late occurrence of spontaneous recurrent seizures in rats

Spontaneous recurrent seizures (SRS) following intrahippocampal kainic acid (KA) injection have been described in a previous paper from our laboratory. The SRSs are clinically similar to the seizures induced by kindling the amygdala and we suggested that the amygdala plays a role in initiating the SRSs. Accordingly, the present paper examines the effect of amygdaloid lesions on intrahippocampal KA-treated rats. There were short- and long-term effects. (1) Short-term: the toxicity of KA was increased in lesioned animals. Status epilepticus followed by death of the animals was evoked with half of the dose required to cause the same effect in intact rats. Moreover, a gross haematuria was encountered 6-12 h after KA injection. This was not observed in non-lesioned rats even following the highest KA doses. (2) Long-term: amygdaloid lesions delayed the occurrence of the SRSs, reduced their incidence and modified their expression. In lesioned animals seizures began with a period of tonic immobility with no sign of the masticatory movements seen in intact animals. Histological examination of the KA-induced lesions did not show any major differences between lesioned and intact animals. It is suggested that the short-term effects are due to an unspecific effect on homeostatic mechanisms, whereas the long-term ones reflect a specific involvement of the amygdala in the late appearing seizures.     

Removal and recovery of Cr(VI) from polluted ground waters: a comparative study of ion-exchange technologies

The focus of this work has been the study of Cr(VI) removal from ground waters and the simultaneous concentration for its reuse using three different technological alternatives: anion-exchange resins, liquid-liquid extraction assisted by hollow fibre membranes and emulsion pertraction. The viability of the considered objectives, i.e., Cr(VI) separation (<0.5 g/m3) and concentration for reuse (>20,000 g/m3) has been checked and a comparative analysis of the three technologies has been performed. Although the flexibility and ease of operation of non-dispersive solvent extraction, anion-exchange resins and emulsion pertraction lead to higher velocities of chromium removal, yet still maintaining similar concentration efficiencies.     

Validation of BaIn0.3Ti0.7O2.85 as SOFC Electrolyte with Nd2NiO4, LSM and LSCF as Cathodes

Due to its high ionic conductivity level, BaIn_0.3Ti_0.7O_2.85 (BIT07) is a potential electrolyte material for SOFC. In order to validate the use of this material, its chemical, mechanical and electromechanical compatibilities with three classical cathode materials (La_0.7Sr_0.3MnO_{3 – δ} (LSM), La_0.58Sr_0.4Co_0.2Fe_0.8O_{3 – δ} (LSCF) and Nd₂NiO_{4 + δ}) have been tested. The chemical compatibility has been demonstrated by XRD experiments, which show that BIT07 does not react with the cathode materials below 1,000 °C. The mechanical compatibility has been investigated by combining measurements of the thermal expansion coefficients of the cathode materials from X‐ray thermo diffraction and SEM observations. Symmetrical cells cathode/electrolyte/cathode have been studied by electrochemical impedance spectroscopy in order to quantify the quality of the cathode/electrolyte interface and to study the long‐term stability of the cell. The main conclusion of the study is that LSCF presents the best compromise between an acceptable mechanical compatibility and very good electrical properties with BIT07.     

All‐MOS implementation of RC networks for time‐controlled Gaussian spatial filtering

This paper addresses the design and VLSI implementation of MOS‐based RC networks capable of performing time‐controlled Gaussian filtering. In these networks, all the resistors are substituted one by one by a single MOS transistor biased in the ohmic region. The design of this elementary transistor is carefully realized according to the value of the ideal resistor to be emulated. For a prescribed signal range, the MOSFET in triode region delivers an interval of instantaneous resistance values. We demonstrate that, for the elementary 2‐node network, establishing the design equation at a particular point within this interval guarantees minimum error. This equation is then corroborated for networks of arbitrary size by analyzing them from a stochastic point of view. Following the design methodology proposed, the error committed by an MOS‐based grid when compared with its equivalent ideal RC network is, despite the intrinsic nonlinearities of the transistors, below 1% even under mismatch conditions of 10%. In terms of image processing, this error hardly affects the outcome, which is perceptually equivalent to that of the ideal network. These results, extracted from simulation, are verified in a prototype vision chip with QCIF resolution manufactured in the AMS 0.35µm CMOS‐OPTO process. This prototype incorporates a focal‐plane MOS‐based RC network that performs fully programmable Gaussian filtering. Copyright © 2011 John Wiley & Sons, Ltd.     

Deactivation of palladium catalyst in catalytic combustion of methane

Catalytic combustion of natural gas, for applications such as gas turbines, can reduce NO_x emissions. Palladium-on-stabilised alumina has been found to be the most efficient catalyst for the complete oxidation of methane to carbon dioxide and water. However, its poor durability is considered to be an obstruction for the development of catalytic combustion. This work was aimed at identifying the origin of this deactivation: metal sintering, support sintering, transformation or coking.

Catalytic combustion of methane was studied in a 15 mm i.d. and 50 mm length lab reactor and in a 25 mm i.d. pilot test rig on monolithic honeycomb substrates. Experiments were performed at GHSV of 50 000 h⁻¹ in lab test and 500 000 h⁻¹ in pilot test. The catalysts used were palladium on different supports on cordierite substrate. The catalysts were characterised by XRD, STEM, ATG and XPS.

In steady-state conditions, deactivation has been found to be dependent on the air/methane ratio, the palladium content on the washcoat and the amount of washcoat on the substrate. An oscillating behaviour of the methane conversion was even observed under specific conditions, due to the reducibility of palladium oxide PdO to Pd. The influence of the nature of the support on the catalyst deactivation was also investigated. It has been shown that some supports can surprisingly eliminate this oscillating behaviour. However, in pilot test, deactivation was found to be very rapid, even with stabilised alumina supports. Furthermore, successive tests performed on the same catalyst revealed that the activity (light-off temperature, conversion) falls strongly from one test to another.

Then, the stabilised alumina support was calcined at 1230°C for 16 h prior to its impregnation by palladium, in order to rule out its sintering. Experiments carried out on precalcined catalysts point out that deactivation is mostly correlated to the metal transformation under reaction conditions: activity decreases gradually as PdO sinters, but it dropped much more steeply in relation to appearance of metallic palladium.     

Preparation and characterization of a macroporous agarose monolith as a stationary phase in IMAC chromatography

A macroporous monolith used as stationary phase for the separation of biomolecules by immobilized metal ion affinity chromatography (IMAC), based on D5 agarose (D5) chemically modified was proposed. The characterization of physical properties was studied. Pressure drop was <0.4?MPa, being a very low value compared to other similar chromatographic supports. The adsorption/desorption process was carried out using bovine serum albumin (BSA) at pH 7.4 as a target protein. The monolith was re-used for 20 adsorption/desorption cycles and it was possible to verify that the average percentage of adsorption in all cycles was 89.65%. It was also possible to apply a model in order to obtain the kinetic adsorption constant (k_a), desorption constant (k_d) and equilibrium constant (K_e) by the proposed system. These results indicate that this system is governed by the adsorption process.     

Sensory analysis integrated by palynological and physicochemical determinations plays a key role in differentiating unifloral honeys of similar botanical origins (Myrtaceae honeys from southern Spain)

Myrtaceae honeys produced in Sierra Morena (southern Spain, Andalusia) are obtained from both Eucalyptus camaldulensis and Myrtus communis, and honeys can be easily confused when classified as they come from the same botanical family. The characterisation was intended on the basis of their physicochemical, sensory and palynological properties. Cluster analysis (CA) and principal component analysis (PCA) allowed us to make a distinction between two honey profiles. The first one corresponds to the European sensory profile described for Eucalyptus unifloral honeys. The second profile, which sensory characteristics are absolutely different, has not been previously described. Classification of samples is proposed to be based on their pollen type and content and sensory attributes. Therefore, pollen type and content in E. camaldulensis and M. communis are required to distinguish Eucalyptus honey type from other honeys coming from Myrtaceae family. Sensory analysis identifies honey botanical source as well as palynological analysis: Eucalyptus sensory profile requires over 50% of E. camaldulensis and under 30% of M. communis pollen. Previously undefined sensory profile of myrtle honey is showed under 50% of E. camaldulensis and over 30% of M. communis pollen.