The growth and aflatoxin production of Aspergillus flavus strains on a cheese model system are influenced by physicochemical factors

Traditional cheeses may be contaminated by aflatoxin-producing Aspergillus flavus during the ripening process, which has not been sufficiently taken into account. The objectives of this study were to evaluate the influence of water activity (a_w), pH, and temperature on the lag phases, growth, and aflatoxin production of 3 A. flavus strains (CQ7, CQ8, and CG103) on a cheese-based medium. The results showed that the behavior of A. flavus strains was influenced by pH, a_w, and temperature conditions. The CQ7 strain showed the maximum growth at pH 5.5, 0.99 a_w, and 25°C, whereas for CQ8 and CQ103 strains, no differences were obtained at pH 5.5 and 6.0. In general, low pH, a_w, and temperature values increased the latency times and decreased the growth rate and colony diameter, although a_w and temperature were the most limiting factors. Maximum aflatoxin production on the cheese-based medium occurred at pH 5.0, 0.95 a_w, and 25 or 30°C, depending on the strain. This study shows the effect of pH, a_w, and temperature factors on growth and aflatoxin production of 3 aflatoxigenic A. flavus strains on a cheese-based medium. The findings may help to design control strategies during the cheesemaking process and storage, to prevent and avoid aflatoxin contamination by aflatoxigenic molds.     

A Project Strategic Index proposal for portfolio selection in electrical company based on the Analytic Network Process

In this paper a new approach to prioritize project portfolio in an efficient and reliable way is presented. It is based on strategic objectives of the company and multicriteria decision methods.The paper introduces a rigorous method with acceptable complexity which seeks to assist managers of a big Electrical Company of Venezuela to distribute the annual budget among the possible improvement actions to be conducted on the electrical network of Caracas. A total of 15 network improvement actions grouped into three clusters according to the strategic objectives of the company have been analyzed using the Project Strategic Index (PSI) proposed.The approach combines the use of the Analytic Network Process (ANP) method with the information obtained from the experts during the decision-making process. The ANP method allows the aggregation of the experts’ judgments on each of the indicators used into one Project Strategic Index. In addition, ANP is based on utility ratio functions which are the most appropriate for the analysis of uncertain data, like experts’ estimations. Finally, unlike the other multicriteria techniques, ANP allows the decision problem to be modelled using the relationships among dependent criteria.The participating experts coincided in the appreciation that the method proposed in this paper is useful and an improvement from traditional budget distribution techniques. They find the results obtained coherent, the process seems sufficiently rigorous and precise, and the use of resources is significantly less than in other methods.     

Bottom‐up performance analysis of focal‐plane mixed‐signal hardware for Viola–Jones early vision tasks

Focal‐plane mixed‐signal arrays have traditionally been designed according to the general claim that moderate accuracy in processing is affordable. The performance of their circuitry has been analyzed in these terms without a comprehensive study of the ultimate consequences of such moderate accuracy. In this paper, for the first time to the best of our knowledge, we do carry out this study. We move expectable performance of mixed‐signal image processing hardware directly into the vision algorithm making use of it. This permits to close a wider design loop, enabling a more aggressive design of this kind of hardware provided that the algorithm, at the highest level—semantic interpretation of the scene—, can afford it. Thus, we present a thorough analysis of the non‐idealities associated with the implementation of a QVGA array tailored for the distinctive characteristics of the Viola–Jones processing framework. The resulting deviation models are then introduced in the processing flow of this framework provided by the OpenCV library. We have found, contrary to what could be expected, that these deviations do not necessarily degrade the performance of the Viola–Jones algorithm. They could be even beneficial for certain high‐level specifications. Additionally, we demonstrate the architectural advantages of our approach: exploitation of focal‐plane distributed memory and ultra‐low‐power operation. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimisation of oil extraction from sardine (Sardina pilchardus) by hydraulic pressing

The aim of this study was to evaluate the influence of the processing conditions (pretreatment temperature: 5–55 °C, pressure: 60–120 bar and number of pressing stages: 1–3) on the yield and quality (free fatty acids, peroxide value, p‐anisidine and Rancimat induction period) of the oil extracted from whole sardine by hydraulic pressing. Experimental factors were investigated by a designed experiment and optimised by response surface methodology. A maximum yield of oil, 12.47%, was obtained at 55 °C, 60 bar and two pressing stages. Regarding oil quality, it was found minimum values for acidity (0.25% oleic at 55 °C, 60 bar and one pressing stage) and for peroxide value (0.29 meq kg^?1 oil at 5 °C, 60 bar and one pressing stage). Hence, the opposite effect of pretreatment temperature and number of pressing stages on the yield of oil and on its oxidation parameters suggested applying the weighted‐sum method as multiobjective optimisation technique.     

Digital Image Analysis and Visual Evaluation of Orange Juice: Influence of Different Measurements' Conditions

This study assesses the effect of background, surrounding, thickness and dilutions on the colour specifications of orange juice (OJ) analyzed by digital image and visual evaluation. A commercial OJ was diluted with distilled water to give ten levels of concentration (100, 90, 80, 70, 60, 50, 40, 30, 20 and 10 % of juice). These samples were evaluated instrumentally by digital image analysis using nine combinations of surroundings and backgrounds (black, grey and white) and three different thicknesses. Visual evaluation was also carried out on black, grey and white backgrounds. A grey surrounding, a white background and a fixed thickness are suggested to be used in future measurements of OJ colour by digital image analysis. Results of visual evaluation indicated that panellists were able to order correctly the OJ samples according to the dilution level, independently of the background chosen. The correlations between the instrumental and the visual analysis were significant (p?<?0.05) in all the backgrounds explored.     

Effect of low-intensity hippocampal stimulation on spatial versus working memory in rats.

Investigated differing predictions from the spatial mapping hypothesis of hippocampal function proposed by O'Keefe and Nadel (1978) and the working memory hypothesis proposed more recently by Olton and colleagues (Olton, Becker, & Handelmann, 1979). Each of 2 groups of rats was trained to use a different strategy to locate a submerged platform in opaque water. The MAP group used a spatial mapping strategy to reach a platform in a fixed location, whereas the CUE group used a guidance strategy, which involved following a cue that signaled the location of a randomly placed platform. Half of each group was given low-level unilateral electrical stimulation of the dentate gyrus and immediately tested on the water maze task. Results of Exp 1 show that both the MAP and CUE groups were impaired by stimulation. However, there was an inadvertent spatial element involved in the CUE task. When this element was eliminated in Exp 3, the same CUE Ss were unaffected by a 2nd series of stimulation trials, whereas the MAP Ss continued to show impairment. Results strongly support the cognitive mapping hypothesis and provide little support for the working memory hypothesis of hippocampal function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of Error Mechanisms in Switched-Current Sigma-Delta Modulators

This paper presents a systematic analysis of the major switched-current (SI) errors and their influence on the performance degradation of ΣΔ Modulators (ΣΔMs). The study is presented in a hierarchical systematic way. First, the physical mechanisms behind SI errors are explained and a precise modeling of the memory cell is derived. Based on this modeling, the analysis is extended to other circuits of higher level in the modulator hierarchy such as integrators and resonators. After that, the study is extended to the modulator level, considering two fundamental architectures: a 2nd-order LowPass ΣΔM (2nd-LPΣΔM) and a 4th-order BandPass ΣΔM (4th-BPΣΔM). The noise shaping degradation caused by the linear part of SI errors is studied in the first part of the paper. This study classifies SI non-idealities in different categories depending on how they modify the zeroes of the quantization noise transfer function. As a result, closed-form expressions are found for the degradation of the signal-to-noise ratio and for the change of the notchfrequency position in the case of 4th-BPΣΔMs. The analysis is treated considering both the isolated and the cumulative effect of errors. In the second part of the paper the impact of non-linear errors on the modulator performance is investigated. Closed-form expressions are derived for the third-order harmonic distortion and the third-order intermodulation distortion at the output of the modulator as a function of the different error mechanisms. In addition to the mentioned effects, thermal noise is also considered. The most significant noise sources of SI ΣΔMs are identified and their contributions to the input equivalent noise are calculated. All these analyses have been validated by SPICE electrical simulations at the memory cell level and by time-domain behavioural simulations at the modulator level. As an experimental illustration, measurements taken from a 0.8 μm CMOS SI 4th-BPΣΔM silicon prototype validate our approach.     

Increased attention to the irrelevant dimension increases interference in a spatial Stroop task.

In a spatial Stroop task, it is argued that interference (ITF) results because selective attention is only partially successful. If so, increasing attention to the word should increase ITF. Three experiments, with 88 undergraduates, used the position words above, below, left, and right in incompatible positions to the left, right, or below a fixation point. Exp 1 showed increased ITF with position naming when Ss must be prepared to attend to either the word or its position. Exp 2 required Ss to first name the position of the word and then recall which word had been presented. This resulted in increased ITF with position naming when the word was followed at a short stimulus onset asynchrony by a pattern mask. Exp 3 employed both word reading and position naming and showed that a large reverse Stroop effect occurred with both vocal and manual responses when Ss were prepared to attend to either dimension of the stimulus. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)