Ochratoxin A and citrinin producing species of the genus Penicillium from feedstuffs

In Spain, low ochratoxin A (OTA) levels have been detected in several pork products but there is no information published about the fungi involved in this OTA contamination. It is well known that P. verrucosum is much more frequently found on cereals in countries where they occasionally have OTA problems as in North European countries compared with South Europe where levels of OTA generally seem to be lower or not detected. Much less information is available about citrinin (CIT) and CIT producing species in cereals and their by products. The aim of this study was to determine, identify and characterize the occurrence of potential OTA and CIT producing Penicillium spp. from mixed feeds and raw materials purchased in the Spanish market and used as feedstuffs. A total of 155 Penicillium spp. isolates belonging to 34 species were analyzed in order to know if they are able to produce OTA and/or CIT. From these isolates, 11 P. verrucosum which were characterized by RAPD analyses, produced OTA. Fourteen isolates were CIT producers, 10 isolates of P. verrucosum and 4 of P. citrinum. Although the occurrence and abundance of OTA and CIT Penicillium producing species have been low in our study, our results confirm the potential risk of OTA and CIT production in feeds if stored improperly. Our results also confirm the occurrence of P. verrucosum in South European countries and that it is the only OTA producing Penicillium species in these substrates.     

Bacterial inactivation and quality changes in fresh-cut avocado treated with intense light pulses

This study investigated the impact of intense light pulses (ILP) on inactivation of Listeria innocua and Escherichia coli as well as quality changes in fresh-cut avocado. Cylinders of avocado inoculated with L. innocua or E. coli were placed in plastic trays, which were sealed with a 64-μm-thick polypropylene film (oxygen permeability of 110 cm³ O₂ m⁻² bar⁻¹ day⁻¹ at 23 °C and 0% RH) and subjected to 15 or 30 pulses at fluencies of 0.4 J/cm² per pulse and then stored for 15 days at 5 °C. In addition to L. innocua and E. coli counts, the headspace atmosphere, pH, colour and firmness were measured. The growth of E. coli and L. innocua was more effectively inhibited when increasing treatment intensity. Hence, significant inactivation was obtained in samples treated with 15 and 30 pulses for L. innocua (2.61 and 2.97 log CFU/g, respectively) and E. coli (2.90 and 3.33 log CFU/g, respectively) just after processing. Oxygen concentrations were significantly reduced, whereas CO₂ and ethanol concentrations increased due to product respiration; however, ethylene production was decreased by the effect of ILP treatments. The use of 30 pulses affected the colour and firmness of fresh-cut avocado, causing browning and softening.     

Assessment of antimicrobial activity of coffee brewed in three different ways from different origins

The antimicrobial effect against pathogens such as Staphylococcus aureus, Enterecoccus faecalis, Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli and Salmonella choleraesius was determined in four types of coffee (Coffea arabica L. cv. Colombia, decaffeinated cv. Colombia, cv. Ethiopia and cv. Kenya). Coffee was seen to have significant activity against the growth of food spoilage bacteria. Among the Gram-positive bacteria, coffee was strongly active against S. aureus, moderately active against L. monocytogenes and had a slightly inhibitory effect against E. faecalis. However, coffee samples were found to be less active against Gram-negative bacteria. The results show that espresso Colombia coffee has better antimicrobial activity than filter and Italian coffee with significant differences (p?<?0.05). Taking into account the origin, there were significant differences (p?<?0.05) between Kenya and decaffeinated Colombia, on the one hand, and Ethiopia and Colombia coffee, on the other, the two last showing the highest antimicrobial activity. The antimicrobial activity of the coffee from different origins studied in this paper increased with concentration. Typical coffee compounds were also analysed, and only caffeic and chlorogenic acids showed any inhibitory effect against the growth of all the analysed bacteria. The antibacterial properties of coffee means that it has a promising potential as natural food ingredient to extend the shelf life of foods such as cake, cookies or biscuits, coffee flavoured with shakes, yoghurt.     

A complex network approach to environmental impact assessment

This article proposes a complex network methodology for the process of Environmental Impact Assessment (EIA) that limits subjectivity and reduces uncertainty by incorporating elements of complex systems theory in the stages of identification and assessment of the significance of environmental impacts. The proposed methodology reduces the sources of uncertainty, which emerge from the use of simplified models that analyse the environment-activity interactions in a unidirectional fashion. This proposal determines the significance of environmental impacts through multidirectional or complex causal relationships. Likewise, it limits the subjectivity of the evaluator by using these causality relationships instead of criteria based on the impacts’ attributes. The application of the proposed methodology demonstrates the advantages of (i) prioritizing the impacts according to their capacity to interact with other impacts, and (ii) the possibility to redirect the environmental management plans towards the prevention of impacts of higher complexity and to reduce the importance of derived impacts.

The application of the proposed methodology reveals that the percentage of irrelevant and moderate impacts is reduced, whereas the percentage of severe and critical impacts increase, in comparison to the conventional methodologies.     

Complexity and performance of an Augmented Lagrangian algorithm

Algencan is a well established safeguarded Augmented Lagrangian algorithm introduced in [R. Andreani, E. G. Birgin, J. M. Martínez, and M. L. Schuverdt, On Augmented Lagrangian methods with general lower-level constraints, SIAM J. Optim. 18 (2008), pp. 1286–1309]. Complexity results that report its worst-case behaviour in terms of iterations and evaluations of functions and derivatives that are necessary to obtain suitable stopping criteria are presented in this work. In addition, its computational performance considering all problems from the CUTEst collection is presented, which shows that it is a useful tool for solving large-scale constrained optimization problems.     

Environmental impact estimation of ceramic lightweight aggregates production starting from residues

Within a circular economy approach, this study investigates the environmental impact of lightweight aggregates (LWAs) produced starting from different mixes of different clays with brewery sludge and cattle bone flour ash (CBA), used as poring and fertilizing agents, respectively. The environmental impact was evaluated by means of release tests, insulation capacity, carbon footprint (CFP), and particulate matter emission during pellet firing. Release tests representative of LWAs realistic application showed very high release of phosphate and satisfactory release of potassium. The thermal insulation of the LWAs was tested by thermal imaging camera and resulted highly variable depending on the composition, with the mix containing CBA performing best. This latter composition leads also to the smallest CO₂ equivalent emission, due to the calorific power of CBA, allowing lower consumption of fossil fuels during the LWA production. Finally, total particulate emissions during the thermal treatment resulted similar in terms of mass for all mixes, while differences in terms of particle morphology and composition occurred. Samples containing residue resulted with a quite good release behavior, CFP, and insulation properties, but higher emission of particles, particularly when glass is added.     

Lateral resolution of the scanning tunnelling microscope

A theoretical study of the current distribution in a model which extracts the prominent characteristics of a tip-surface geometry in a scanning tunnelling microscope is presented. The sample is a Sommerfeld metal with a planar surface while the tip, also made of a Sommerfeld metal with a planar surface, presents a hemispherical protrusion. Schrödinger's equation is solved by using a form of the finite element method suitable to treat the three-dimensional tunnelling problem. We have derived the current distribution for several values of the protrusion radius and for various gaps between the electrodes. From these results, we investigate the ideal resolution of the scanning tunnelling microscope for realistic values of these geometrical parameters. Though applied to a rather simple model, at this stage, our method appears to be a suitable scheme for further, more refined computations, accounting for the detailed atomic structure of the electrodes.     

Entamoeba histolyticaelectrondense granules secretion in vitro and in vivo: ultrastructural study

Electron dense granules (EDGs) were identified by transmission electron microscopy in Entamoeba histolytica trophozoites recovered from hamster liver lesions. Abundant granules were present in trophozoites recovered after 15 min of liver inoculation. Variation in the size and morphology of these EDGs was also observed. Numerous granules were present in the plasma membrane when these parasites were incubated for 5 min with MDCK monolayers. Release of these EDGs was suggested by the presence of granules in contact with the surface of the target cell plasma membrane. Parasite phagocytic invaginations were observed after 10 min of parasite-monolayer interaction. In these structures, scarce granules were seen. Granules secretion was corroborated by obtaining of a pellet of these small structures from the incubation of trophozoites with collagen supernatant. Collagenase and gellatinase activity of this pellet was identified in SDS-PAGE gels. EDGs were also present in amebic hamster liver lesions. Our observations corroborate that these granules are secreted and suggest that may participate in the cytopathic effect of E. histolytica both in vitro and in vivo.     

The effects of controlling capture on multimedia traffic for shared Ethernet systems

The IEEE 802.3 Ethernet standard is evolving to support much higher data rates and improved quality of service. Even low cost halfduplex CSMA/CD networks can be improved using an enhanced backwardscompatible collision arbitration algorithm known as the Binary Logarithmic Arbitration Method (BLAM) now being proposed as the IEEE 802.3w draft standard. BLAM is designed to coexist fairly with the existing Binary Exponential Backoff (BEB) algorithm, while eliminating its shortterm unfairness problems. In this paper, we focus on how BLAM improves Ethernet performance for multimedia data transport. Analytical, simulation, and prototype hardware experimental results using synthetic, trace, and actual measured traffic are presented. It is shown that BLAM Ethernets can support significantly greater numbers of video streams than existing BEB Ethernets and if the delivery requirements for the video traffic are not too strict, that BLAM Ethernets can even support video if the network is completely saturated with data traffic.     

Coherent scattering by one-dimensional randomly rough metallic surfaces

A critical evaluation of various theoretical techniques for calculating the reflectivity of one-dimensional metallic randomly rough surfaces is presented. We proceed by comparing experimental and rigorous numerical results with those obtained with three perturbation theories and the Kirchhoff approximation. The samples were fabricated in photoresist, and their metallized surface profiles constitute good approximations to Gaussian-correlated, Gaussian random processes. The correlation lengths of these surfaces range from approximately one third to approximately three times the infrared wavelengths employed. The results show that the phase-perturbation theory has wider applicability than the other perturbation theories and the results based on the Kirchhoff approximation.